U.S. Department of the Interior

U.S. Geological Survey

Nutrient, Trace-Element, and Ecological History

of Musky Bay, Lac Courte Oreilles, Wisconsin,

as Inferred from Sediment Cores

Water-Resources Investigations Report 02–4225

Prepared in cooperation with the

Lac Courte Oreilles Tribe

Wisconsin Department of Agriculture, Trade, and Consumer Protection

MILES

0 KILOMETERS

0 1

1 2

2

Lac Courte Oreilles

Indian Reservation

Grindstone Lake

Durphee

 Lake

Sand Lake

Windigo 

Lake

Musky Bay

Whitefish Lake

Chicago

Bay

Northeastern Bay

Stucky 

Bay

Couderay

 River

Devils 

Lake

Ashegon 

Lake

Billy Boy Flowage Billy Boy Flowage

Little 

Lac Courte 

Oreilles

Lac Courte Oreilles

Study area

WISCONSIN

Squaw Creek

Ghost Creek

Local drainage basin

Open water

Wetland

Stream

Lac Courte Oreilles

Indian Reservation

Core collected in 1999

Core collected in 2001

Drainage basin boundary

EXPLANATION
Nutrient, Trace-Element, and Ecological 

History of Musky Bay, Lac Courte Oreilles, 

Wisconsin, as Inferred from Sediment 

Cores

By Faith A. Fitzpatrick, Paul J. Garrison, Sharon A. 

Fitzgerald, and John F. Elder

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 02–4225

Prepared in cooperation with the

Lac Courte Oreilles Tribe

Wisconsin Department of Agriculture, Trade, and Consumer Protection

Middleton, Wisconsin

2003
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

For additional information write to: Copies of this report can be purchased from:

District Chief U.S. Geological Survey 

U.S. Geological Survey Branch of Information Services

8505 Research Way Box 25286

Middleton, WI 53562-3586 Denver, CO 80225-0286

The use of firm, trade, and brand names in this report is for identification purposes only and does

not constitute endorsement by the U.S. Government.
CONTENTS III

CONTENTS

Abstract ................................................................................................................................................................................. 1

Introduction........................................................................................................................................................................... 1

Purpose and scope....................................................................................................................................................... 4

Acknowledgments....................................................................................................................................................... 5

Historical analysis of lake sediment...................................................................................................................................... 5

Description of study area ...................................................................................................................................................... 6

General characteristics ................................................................................................................................................ 6

Land-use history.......................................................................................................................................................... 7

Cranberry farming............................................................................................................................................. 7

Shoreline development...................................................................................................................................... 9

Study methods....................................................................................................................................................................... 12

Sediment coring and subsampling .............................................................................................................................. 12

Physical characteristics and organic content............................................................................................................... 16

Radiometric dating and sedimentation rates ............................................................................................................... 16

Total organic carbon and nitrogen............................................................................................................................... 22

Minor and trace elements............................................................................................................................................ 22

Biogenic silica............................................................................................................................................................. 22

Diatoms ....................................................................................................................................................................... 23

Pollen .......................................................................................................................................................................... 23

Quality assurance ....................................................................................................................................................... 23

Historical trends from Musky Bay and Northeastern Bay.................................................................................................... 25

Bulk density and organic content................................................................................................................................ 25

Sedimentation rates ..................................................................................................................................................... 26

Nutrients...................................................................................................................................................................... 32

Minor and trace elements ........................................................................................................................................... 36

Biogenic silica, diatom counts, and biovolumes......................................................................................................... 40

Diatom assemblages ................................................................................................................................................... 43

Musky Bay ........................................................................................................................................................ 43

Northeastern Bay............................................................................................................................................... 50

Pollen .......................................................................................................................................................................... 50

Summary and conclusions .................................................................................................................................................... 52

References cited .................................................................................................................................................................... 53

Appendixes:

A. Results from analysis of cores and surficial sediment collected from Lac Courte Oreilles and 

surrounding areas

A1. Results from analysis of water content, loss on ignition, bulk density, and porosity from core samples 

 collected from Lac Courte Oreilles, October 1999 and July 2001................................................................... 60

A2. Results from particle-size analysis of lake and soil samples collected in July 2001 from areas surrounding 

 Lac Courte Oreilles ......................................................................................................................................... 63

A3. Results from analysis of 210Pb, 226Ra, and 137Cs from core samples from Musky and 

 Northeastern Bays, Lac Courte Oreilles, October 1999................................................................................... 64

A4. Results from minor- and trace-element analysis of core samples from Lac Courte Oreilles and 

 surrounding areas, October 1999 and July 2001.............................................................................................. 66

A5. Results from nutrients analysis of core samples from Musky and Northeastern bays, Lac Courte Oreilles,

 October 1999................................................................................................................................................... 75

A6. Results from biogenic silica analysis of core samples from Musky and Northeastern bays, 

 Lac Courte Oreilles, October 1999 ................................................................................................................. 77

A7. Results from analysis of diatom valve concentration from Musky and Northeastern bays, 

 Lac Courte Oreilles, October 1999 ................................................................................................................. 79

A8. Results from analysis of diatom assemblages from Musky Bay, MB-1 and MB-3 cores, 

 Lac Courte Oreilles, October 1999 ................................................................................................................. 80
IV CONTENTS

CONTENTS–Continued

A9. Results from pollen analysis of core samples from Musky and Northeastern bays, Lac Courte Oreilles, 

 October 1999............................................................................................................................................... 129

A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and 

 surrounding areas, October 1999 and July 2001......................................................................................... 134

B. Interpretation of nutrient history for the main basin of Lac Courte Oreilles from diatom assemblages............... 139

FIGURES

1. Map showing Lac Courte Oreilles study area, 1999 and 2001, and location of sediment-core sites ...................... 2

2. Photo of algal masses Musky Bay, viewed west from the southeast corner of Musky Bay in September 1999..... 3

3. Map showing land cover in the Lac Courte Oreilles watershed .............................................................................. 8

4. Map and graph showing expansion of cranberry bogs near Lac Courte Oreilles, 1939 through 1998 ................... 10

5–10. Graphs showing:

5. Shoreline development on four bays on Lac Courte Oreilles............................................................................ 11

6. Comparison of the diameter of wild rice pollen grains from Irving Lake, Wisconsin and Musky Bay, Lac 

Courte Oreilles, Wisconsin ................................................................................................................................... 24

7. Bulk density and organic content data from loss on ignition for cores collected from Musky Bay and

Northeastern Bay, October 1999..................................................................................................................... 27

8. Comparison of radiometric data for Musky Bay core and Northeastern Bay core collected in 

October 1999................................................................................................................................................... 28

9. Best-fit log-linear curve (regression line) for unsupported 210Pb activity used in the constant initial 

concentration model........................................................................................................................................ 30

10. Comparison of dates and sedimentation rates from the constant rate of supply (CRS), adjusted 

CRS, 137Cs, and constant initial concentration (CIC) models for Musky Bay core MB-1 ............................ 31

11. Concentration profiles of total organic carbon, total nitrogen, total phosphorus, and total sulfur in

Musky Bay core MB-1A and Northeastern Bay core LCO-1A......................................................................... 33

12. Mole-ratio profiles of OC:N, N:P, and OC:P for Musky Bay core MB-1A ......................................................... 35

13. Profiles of nitrogen (N) and phosphorus (P) normalized to aluminum (Al) and organic content (LOI) in 

Musky Bay core MB-1A.................................................................................................................................... 37

14. Profiles of selected minor and trace elements in Musky Bay core MB-1A and Northeastern (NE) Bay core 

LCO-1A for aluminum, calcium, copper, and lead............................................................................................ 38

15. Profiles of selected minor and trace elements normalized to aluminum in Musky Bay core MB-1A ................. 39

16. Comparison of profiles of biogenic silica concentrations in Musky and Northeastern Bays ............................... 42

17. Comparison of profiles of biogenic silica, diatom concentration, and biovolume in Musky Bay core MB-1 ..... 42

18. Profiles of selected diatoms in Musky Bay core MB-1B, October 1999.............................................................. 44

19. Profiles of selected diatoms in Musky Bay core MB-3, October 1999 ................................................................ 45

20. Profiles of selected diatoms in Northeastern Bay core LCO-1B, October 1999 .................................................. 46

21. Comparison of diatom assemblages in side-by-side cores collected from Musky Bay core MB-1, 

October 1999...................................................................................................................................................... 47

22. Profiles of planktonic diatoms, small Navicula, and benthic Fragilaria for two cores in Musky Bay 

(MB-1B and MB-3) and one core in Northeastern Bay (LCO-1B), October 1999 ........................................... 48

23. Pollen diagram from Musky Bay core MB-3, October 1999................................................................................ 51
CONTENTS V

CONTENTS–Continued

TABLES

1. Density of houses along selected bays in Lac Courte Oreilles ................................................................................ 11

2. Description of cores collected by the U.S. Geological Survey and Wisconsin Department of Natural 

Resources from Lac Courte Oreilles, October 1999 ............................................................................................ 13

3. Brief lithologic description of cores collected by the U.S. Geological Survey and Wisconsin Department of

Natural Resources from Lac Courte Oreilles, October 1999 ............................................................................... 14

4. Description of cores collected by the U.S. Geological Survey from Lac Courte Oreilles and nearby lakes, 

soils, fertilizer, and wetland, August 2001........................................................................................................... 15

5. Summary of laboratory analyses on two cores from Musky Bay (MB-1 and MB-3) and one core from 

Northeastern Bay (LCO-1) collected in October 1999 ........................................................................................ 17

6. Estimated average mass and linear sedimentation rates from the CRS model, adjusted CRS model, 

CIC model, and 137Cs activity for Musky Bay core MB-1, Lac Courte Oreilles, October 1999 ........................ 29

7. Molar ratios of organic carbon, nitrogen, and phosphorus in Musky Bay core MB-1A, 1999................................ 35

8. Concentrations of organic content, arsenic, chromium, copper, lead, nickel, and zinc in selected surficial 

sediment from Lac Courte Oreilles and surrounding areas, 1999 and 2001........................................................ 41
VI CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATED UNITS OF MEASUREMENT

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATED UNITS OF MEASUREMENT

Multiply By To Obtain

micrometer (μm) 3.937x10-5 inch

millimeter (mm) 0.03937 inch

centimeter (cm) .3937 inch

meter (m) 3.2808 feet

kilometer (km) .62137 miles

square kilometer (km2) 247.105 acres

square kilometer (km2

) .3861 square miles

cubic kilometer (km3) 4.168 cubic miles

hectare (ha) 2.47105 acres

micrograms (μg) 2.2x10-9 pounds

gram (g) .0022 pounds

kilogram (kg) 2.2046 pounds

Temperature, in degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) by use of the following equation:

°F=1.8(°C) + 32.

Vertical Datum: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)a geodetic datum 

derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

Abbreviated units of measurement used in this report: Physical measurements and chemical concentrations and water temperature are 

given in metric units. Radiometric concentration is given in picoCuries per gram (pCi g-1). Sediment chemical concentration is given in 

micrograms per gram (μg g-1), millimoles per gram (mmol g-1), or parts per million (ppm). Bulk density is given in grams per cubic centimeter (g cm-3). Sediment accumulation rate is given in grams per square centimeter per year (g cm-2 y-1). Linear sedimentation rate is given 

in centimeters per year (cm y-1). Normality (N) is given as equivalents per liter, where equivalent is the mass of a compound per equivalent 

weight and equivalent weight is the molar mass per H+ per mole.
Abstract 1

Abstract

Sediment cores were collected from Musky Bay, 

Lac Courte Oreilles, and from surrounding areas in 

1999 and 2001 to determine whether the water quality 

of Musky Bay has declined during the last 100 years or 

more as a result of human activity, specifically cottage 

development and cranberry farming. Selected cores 

were analyzed for sedimentation rates, nutrients, minor 

and trace elements, biogenic silica, diatom assemblages, and pollen over the past several decades. Two 

cranberry bogs constructed along Musky Bay in 1939 

and the early 1950s were substantially expanded 

between 1950–62 and between 1980–98. Cottage development on Musky Bay has occurred at a steady rate 

since about 1930, although currently housing density on 

Musky Bay is one-third to one-half the housing density 

surrounding three other Lac Courte Oreilles bays. Sedimentation rates were reconstructed for a core from 

Musky Bay by use of three lead radioisotope models 

and the cesium-137 profile. The historical average mass 

and linear sedimentation rates for Musky Bay are 

0.023 grams per square centimeter per year and 

0.84 centimeters per year, respectively, for the period of 

about 1936–90. There is also limited evidence that sedimentation rates may have increased after the mid1990s. Historical changes in input of organic carbon, 

nitrogen, phosphorus, and sulfur to Musky Bay could 

not be directly identified from concentration profiles of 

these elements because of the potential for postdepositional migration and recycling. Minor- and trace-element profiles from the Musky Bay core possibly reflect 

historical changes in the input of clastic material over 

time, as well as potential changes in atmospheric deposition inputs. The input of clastic material to the bay 

increased slightly after European settlement and possibly in the 1930s through 1950s. Concentrations of copper in the Musky Bay core increased steadily through 

the early to mid-1900s until about 1980 and appear to 

reflect inputs from atmospheric deposition. Aluminumnormalized concentrations of calcium, copper, nickel, 

and zinc increased in the Musky Bay core in the mid1990s. However, concentrations of these elements in 

surficial sediment from Musky Bay were similar to concentrations in other Lac Courte Oreilles bays, nearby 

lakes, and soils and were below probable effects concentrations for aquatic life. Biogenic-silica, diatomcommunity, and pollen profiles indicate that Musky Bay 

has become more eutrophic since about 1940 with the 

onset of cottage development and cranberry farming. 

The water quality of the bay has especially degraded 

during the last 25 years with increased growth of aquatic 

plants and the onset of a floating algal mat during the 

last decade. Biogenic silica data indicate that diatom 

production has consistently increased since the 1930s. 

Diatom assemblage profiles indicate a shift from lownutrient species to higher-nutrient species during the 

1940s and that aquatic plants reached their present density and/or composition during the 1970s. The diatom 

Fragilaria capucina (indicative of algal mat) greatly 

increased during the mid-1990s. Pollen data indicate 

that milfoil, which often becomes more common with 

elevated nutrients, became more widespread after 1920. 

The pollen data also indicate that wild rice was present 

in the eastern end of Musky Bay during the late 1800s 

and the early 1900s but disappeared after about 1920, 

probably because of water-level changes more so than 

eutrophication.

INTRODUCTION

Lac Courte Oreilles is located in and near the 

Indian Reservation of the Lac Courte Oreilles Band of 

Lake Superior Ojibwa in northwestern Wisconsin 

(fig. 1). As the second largest water body in the reservation, it has been nearly free of water-quality problems in 

the past, and it supports an abundance of aquatic life, 

Nutrient, Trace-Element, and Ecological History of Musky 

Bay, Lac Courte Oreilles, Wisconsin, as Inferred from 

Sediment Cores

By Faith A. Fitzpatrick, Paul J. Garrison1, Sharon A. Fitzgerald, and John F. Elder 

1

Wisconsin Department of Natural Resources, Monona, Wis.
2 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 1. Lac Courte Oreilles study area, 1999 and 2001, and location of sediment-core sites.

Base from U.S Geological

Survey 1:24,000 digital data 

MILES

0 KILOMETERS

0 1

1 2

2

SB-1

JON-1

LCO-2

ASH-1

DEV-1

SAN-1

MB-2

MB-3

MB-5

LEV-1

MB-4

MB-1

MB-3

LEV-1

SB-1

SB-2

Lac Courte Oreilles

Indian Reservation

Grindstone Lake indstone Lake

Durphee

 Lake

Sand Lake

Windigo 

Lake

Musky Bay

Whitefish Lake

Chicago

Bay

Northeastern Bay

Stucky 

Bay

Couderay

 River

Devils 

Lake

Ashegon 

Lake

Billy Boy Flowage Billy Boy Flowage

Little 

Lac Courte 

Oreilles

Lac Courte Oreilles

Local drainage basin

Open water

Wetland

Stream

Lac Courte Oreilles

Indian Reservation

Core collected in 1999

Core collected in 2001

EXPLANATION

SAN-1 Site name

Hydrologic data from Wisconsin

Department of Natural Resources

Study area

WISCONSIN

Squaw Creek

Ghost Creek

LCO-3

LCO-1

ZAW-1

WET-1

Drainage basin boundary
INTRODUCTION 3

including various sport-fish species. For centuries, 

Native Americans have depended on the water 

resources, fisheries, and natural crops (such as wild 

rice) provided by Lac Courte Oreilles and other nearby 

lakes.

Recently, however, there have been concerns about 

deterioration of water quality and fish habitats in the 

lake. The problems are manifested by increased growth 

of algae, decreased water clarity, and diminished fish 

populations. The problem is particularly acute in Musky 

Bay, in the southwestern part of the lake. Thought to be 

the former site of wild rice beds and frequent spawning 

grounds for muskellunge, Musky Bay currently is 

devoid of wild rice, and muskellunge spawning areas 

are thought to have declined. Macrophytes (aquatic 

plants) and algal masses often cover some of the water 

surface (fig. 2). The Lac Courte Oreilles Tribe is concerned that the aerial spraying of fertilizer on cranberry 

farms south of the Musky Bay has increased nutrient 

loadings to the Bay (Barr Engineering, 1998).

The deterioration of water quality and clarity and 

increase of algal growth and macrophytes, known as 

eutrophication, is a process caused by increased inputs 

of nutrients, particularly nitrogen and phosphorus. All 

lakes receive natural and anthropogenic inputs of nutrients from tributaries, the atmosphere, and ground water. 

For example, in a study of the phosphorus budget of 

Balsam Lake, in northwestern Wisconsin, the annual 

phosphorus input to the lake was comprised of tributary 

inputs (79–81 percent), precipitation (7–12 percent), 

and ground water (4–7 percent) (Rose, 1993). It is not 

known whether human-induced eutrophication, also 

called cultural eutrophication, has affected Lac Courte 

Oreilles, but it is a distinct possibility. A recent modeling study of nutrient loads to Lac Courte Oreilles (Barr 

Engineering, 1998) estimated that nearby cranberry 

bogs contributed 44 percent of the annual phosphorus 

load to Musky Bay at that time. Houses and associated 

lots, mainly seasonal dwellings, also are present along 

the shoreline of the bay and may supply nutrients 

through fertilizer runoff and septic-tank leakage. A 

potentially large source of nutrients is the lake bottom, 

where algal material decomposes and some nutrients 

Figure 2. Algal masses in Musky Bay, viewed west from the southeast corner of Musky Bay in September 

1999. (Photograph by P.J. Garrison, Wisconsin Department of Natural Resources.)
4 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

from algal decomposition re-enter the lake and become 

available for primary production.

The Lac Courte Oreilles Tribe is interested in 

assessing the importance of nutrient loading from 

cranberry bogs and shoreline development relative to 

natural inputs, particularly for Musky Bay. One way to 

evaluate the relative importance of natural and anthropogenic changes in water quality is to examine historical inputs of nutrients and ecological response as 

reconstructed from sediment cores. The sediment 

record commonly preserves observable trends in nutrient cycles and ecosystem character over the last few 

hundred years, a time that includes a background period 

and the period of cranberry farming and shoreline 

development in Lac Courte Oreilles. 

The study described in this report focuses on the 

nutrient history of Musky Bay through the analysis of 

sediment cores collected in 1999 and 2001. The study 

was initiated by the Lac Courte Oreilles Tribe in 

response to the Barr Engineering (1998) report and 

involved a cooperative effort among the Lac Courte 

Oreilles Tribe; the U.S. Geological Survey; the Wisconsin Department of Natural Resources; the Wisconsin 

Department of Agriculture, Trade, and Consumer Protection; and the Wisconsin Cranberry Growers Association. The major objective of this study was to 

reconstruct the history of water quality and ecological 

changes in Musky Bay and at an additional site in the 

northeastern end of Lac Courte Oreilles called Northeastern (NE) Bay (also locally known as Barbertown 

Bay). Changes in historical nutrient conditions in 

Musky Bay were of primary interest. Sediment cores 

were also collected from other bays in Lac Courte 

Oreilles and from the central, deep basin of the lake. A 

core from NE Bay was selected for comparisons of diatom counts, sediment-accumulation rates, nutrient content, and geochemical analysis because it has shoreline 

development but does not receive discharge from a 

cranberry operation.

The principal focus of the investigation of sediment 

cores was on the nutrient history (input and burial rates) 

that reflects management practices and possible Musky 

Bay degradation. Reconstructed algal (mainly diatom) 

communities and biogenic silica profiles were used as 

surrogates for actual nutrient input histories. Pollen 

analysis was also used to identify major historical 

changes in aquatic and terrestrial vegetation. Another 

objective was, if possible, to distinguish temporally the 

nutrients derived from cranberry farming and shoreline 

development from those derived from natural sources. 

This study focused on sediment analysis and did not 

include water sampling or monitoring of water quality.

Sediment samples from cores collected from 

Musky and NE Bay in 1999 were analyzed for sedimentation rates, nutrients, minor and trace elements, diatom 

community, biogenic silica, and pollen. Additional 

cores were collected from Musky Bay, Stucky Bay, and 

the central, deep basin of Lac Courte Oreilles; a subset 

of samples were analyzed from these cores. In August 

2001, surficial sediment from Lac Courte Oreilles bays 

and nearby lakes was collected to determine the source 

of elevated cadmium concentrations observed in 1999 

core samples from the Lac Courte Oreilles bays. The 

nearby lakes sampled included a remote lake with no 

cranberry bogs or shoreline development (Devils Lake) 

and two lakes with only shoreline development and no 

cranberry bogs (Sand Lake and Ashegon Lake, fig. 1). 

Samples of soil and fertilizer from cranberry bogs on 

Musky and Stucky bays and soil from a remote wetland 

also were analyzed.

Purpose and Scope

The main purpose of this report is to document the 

findings from the nutrient-history analysis and 

geochemical characterization of Musky Bay, Lac 

Courte Oreilles. Specific objectives of the study were to 

answer the following questions about Musky Bay: 

(1) Have sedimentation rates increased? 

(2) Have minor- and trace-element 

concentrations in sediment changed over 

time? 

(3) Have increased nutrient inputs caused Musky

Bay to become more eutrophic?

(4) Have the diatom and plant community, including wild rice (Zizania palustris L.), changed

over time?

(5) Have nutrient inputs increased as a result of

changes in land cover since European settlement? 

This report describes all aspects of the study. First, 

methods used for sample collection are described. Second, interpretations of historical trends in sedimentation 

rates, minor and trace elements, nutrients, biogenic silica, diatom assemblages, and pollen are described for 

Musky Bay and compared to what was found for NE 

Bay. Third, minor- and trace-element concentrations of 

surficial sediment from Musky Bay are compared to 

those is other bays in Lac Courte Oreilles (NE Bay and 
HISTORICAL ANALYSIS OF LAKE SEDIMENT 5

Stucky Bay), and other nearby lakes, soils, and fertilizer. Finally, interpretations and implications of the 

findings of this study for management activities are presented.

Acknowledgments

We wish to express our gratitude for field assistance during coring, including help from Dan Tyrolt and 

Brett McConnell (Lac Courte Oreilles Environmental 

Section), Harry Schroeder (Lac Courte Oreilles Lake 

Association), and Kevin Richards (USGS). The additional geochemical sampling was made possible 

through the legwork of Randall Jonjak. We are very 

appreciative for access to cranberry bogs for soil and 

fertilizer samples for minor and trace-element sampling 

from Randall Jonjak and William Zawistowski. The 

Levake family provided shoreline access to Musky Bay. 

We are very thankful for the special assistance from 

Rick Sanzolone (USGS, Geologic Division Laboratory, 

Denver, Colo.) for running blank sediment samples and 

expediting our minor- and trace-element samples; and 

from Bill Orem and Terry Lerch (USGS, Geologic Division Laboratory, Reston, Va.) for analyzing our carbon 

and nitrogen samples. The USGS, Caribbean District, 

provided logistical support and lab space for the biogenic silica analysis and office facilities for report preparation. John Meier (Wisconsin DNR) retrieved 

cadmium emission data for us for northern Wisconsin.

James Kennedy, Marie Peppler, and Michelle 

Greenwood (all with the USGS) made the map and 

graph illustrations for the report. Marie Peppler, Kathleen Wang, and Susan Jones (all with the USGS) compiled and formatted the data for the tables in the report 

and appendix A. Michael Eberle and Leah Hout 

(USGS), Michelle Lutz (USGS), and Heather Whitman 

(USGS) provided editorial reviews of the draft manuscript. This report has benefited from the thorough, critical reviews and insightful suggestions from Dr. 

Margorie Winkler (University of Wisconsin-Madison), 

Dr. Mark Hermanson (University of Pennsylvania), and 

Peter Van Metre (USGS).

HISTORICAL ANALYSIS OF LAKE 

SEDIMENT

Questions often arise concerning how the water 

quality of a lake has changed through time as a result of 

watershed disturbances. In most cases, reliable longterm data are unavailable. The central questions are: 

what were the past conditions of the lake, did the condition of the lake change, when did this occur, and what 

were the causes? 

Under ideal circumstances, reconstruction of 

changes in the lake ecosystem over any period of time 

since the establishment of the lake can be accomplished 

by collecting sediment cores and examining nutrients, 

minor and trace elements, and fossil remains found in 

the sediment. Lake sediments can integrate effects from 

an entire watershed and are therefore a convenient 

record of water-quality and aquatic-life responses to 

change, including human activities (Engstrom and others, 1985; Charles and others, 1994; Schelske and others, 1988). For example, organic matter often 

accumulates at increased rates as a result of cultural 

eutrophication (Fitzgerald, 1989). 

Reconstruction of historical diatom assemblages 

through analysis of sediment cores can be useful for 

determining historical changes in nutrient inputs (Hall 

and Smol, 1999). Diatoms, a diverse and usually abundant type of algae that possess siliceous cell walls (frustules), are especially useful in sediment-core analysis 

because they are ecologically diverse and well preserved in sediments; moreover, the ranges of favorable 

environmental conditions are known for several species. 

Most diatoms used as water-quality indicators grow rapidly and are short lived, so the diatom-community composition responds rapidly to changing environmental 

conditions. Certain genera and species are usually 

found under nutrient-poor conditions, whereas others 

are more common at elevated nutrient concentrations. 

Some diatom species are sensitive to eutrophication. 

Diatoms also live under a variety of habitats, which 

enables potential reconstruction of changes in nutrient 

concentrations in the open water as well as changes in 

lake-bottom environments such as changes in aquaticplant communities. In many lakes throughout Wisconsin, diatom and aquatic plant communites in the littoral zone (shallow water zone where rooted plants can 

live) have undergone significant changes as nutrient loading from the watershed increased (Garrison and Winkelman, 1996; Marshall and others, 1996; Garrison and 

Wakeman, 2000). Typically these changes include 

expansion of the submerged-plant community. 

In addition to diatoms, lake sediments entomb a 

selection of siliceous fossil remains that are more or less 

resistant to bacterial decay or chemical dissolution, 

including cell walls of certain algal species and subfos-
6 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

sils from emergent and submergent aquatic plants, such 

as wild rice. Profiles of biogenic silica (silica derived 

from biological sources) from sediment cores can be 

used as supporting evidence for historical reconstructions of diatom communities and production and as an 

indicator of species shifts (largely from diatoms to nonsiliceous algae) in response to increased nutrient inputs 

(Schelske and others, 1983; Conley, 1988; Schelske and 

others, 1988; Qui and others, 1993; Colman and others, 

1995; Schelske, 1999; Wessels and others, 1999). In the 

Laurentian Great Lakes, for example, relatively small 

increases in phosphorus due to human activity produced 

relatively large shifts in the accumulation of biogenic 

silica and organic and inorganic carbon in sediments 

(Schelske and others, 1988; Schelske, 1999; Taylor, 

1999). Thus, the accumulation rates of biogenic silica 

and diatoms—which tend to persist in sediment—have 

been shown to record the effects of increased phosphorus inputs to a lake even when sedimentary phosphorus 

profiles do not. Phosphorus has been shown to be 

affected by different factors that obscure phosphorus 

input history but not the biogenic silica history (Schelske and others, 1986).

Human activities such as shoreline development 

and cranberry farming could alter the input, recycling, 

and burial rates of organic carbon and nutrients. If 

trends in nutrient inputs can be discerned from diagenesis (chemical, physical, and biological changes that 

occur after initial deposition), then these trends can be 

related to known dates and types of land-use practices in 

the watershed. If they can be developed sufficiently, 

nutrient profiles in sediments can be used to estimate 

trends in historical concentrations in lake water during 

times for which no chemical analyses are available. 

Increased input rates of organic matter and nutrients 

may result in concomitant increases in recycling (more 

dissolved nutrients returning to the overlying water), 

burial (more nutrients removed from the lake ecosystem), or both. The magnitude of any changes in recycling and burial will be reflected to a certain extent in 

the profiles of organic carbon, nitrogen, phosphorus, 

and sulfur, among others. Historical changes in ratios of 

organic carbon, nitrogen, and phosphorus may reflect 

changes in nutrient concentrations and changes in the 

relative amounts of terrestrial versus aquatic organic 

matter in the lake. These ratios may also reflect relative 

rates of organic carbon, nitrogen, and phosphorus 

diagenesis (Orem and others, 1991; Fitzgerald, 1989). 

Elements and compounds that tend not to recycle, 

and therefore leave a good input history include those 

within the mineral part of the sediment. Some mineral 

elements, such as aluminum and titanium, are not 

readily recycled under commonly occurring biogeochemical conditions within sediment. Aluminum 

and titanium are almost entirely associated with eroded 

soil and rock in lake sediments, and their profiles reflect 

changes in soil erosion rates (Engstrom and Wright, 

1984). Some elements can be associated with land-use 

practices; for example, potassium is common in soils, 

but it also may be a major component in commercial 

fertilizers. Sulfur, uranium, and cadmium also may be 

present in fertilizers. Copper is sometimes used in fungicides and herbicides for cranberry farming. Other 

mineral-associated elements are not a good reflection of 

input rates, such as iron and manganese, which are 

redox sensitive elements that may undergo post-depositional diagenesis (Engstrom and others, 1985). Thus, 

like nutrient profiles, iron and manganese profiles may 

likely not record true input histories. 

DESCRIPTION OF STUDY AREA

General Characteristics

Lac Courte Oreilles is in the Upper Chippewa River 

Basin in Sawyer County in northwestern Wisconsin 

(fig. 1). Lac Courte Oreilles is a drainage lake (its main 

inflows and outflows are surface water), although 

ground-water inflow to the lake also is substantial 

(Water Resources Management Program, University of 

Wisconsin-Madison, 1991). The lake is fed by Squaw 

Creek (flowing into NE Bay), Ghost Creek, Whitefish 

Creek (from Whitefish Lake), and Grindstone Lake. 

The immediate drainage of the lake (excluding Grindstone and Whitefish Lakes) is 78.9 km2

 (fig. 1). The outlet is on the southeast side into Little Lac Courte 

Oreilles and eventually into Billy Boy Flowage and the 

Couderay River. The outlet on Billy Boy Flowage is 

controlled by a dam, which started out as a logging 

structure of unknown age and head. Water levels in Lac 

Courte Oreilles, Little Lac Courte Oreilles, and Billy 

Boy Flowage are currently similar (within about 50 cm) 

based on water level data from Sawyer County records. 

In about 1936 the structure was replaced with a new 

dam with a head of about 3.5 m. The head was reduced 

to 3 m in 1954 and has been at that level since then. Historical water level readings suggest that the new dam 

raised water levels in Billy Boy Flowage by about 2 m 
DESCRIPTION OF STUDY AREA 7

between 1937 and 1940. It is not known how much this 

change at the Billy Boy Dam affected the water level of 

Lac Courte Oreilles.

With a surface area of 2,039 ha, a maximum depth 

of 27 m, and an average depth of 10.4 m, Lac Courte 

Oreilles has a volume of about 0.2 km3

. In most years, 

it follows a typical dimictic cycle— its waters mix completely in the fall and the spring, and it develops thermal 

stratification in summer and winter. Musky Bay has a 

surface area of 103 ha and a mean depth of 2.0 m. The 

NE Bay has a surface area of 25 ha and a mean depth of 

4.6 m (Barr Engineering, 1998). 

The nutrient conditions and biological productivity 

of Lac Courte Oreilles are generally characteristic of a 

mesotrophic lake (moderate productivity and water 

quality) during most of the growing season (Barr Engineering, 1998). During the later summer and fall 

months, its condition often improves to oligotrophic 

(clear water with low productivity). However, Musky 

Bay, which is somewhat isolated and shallower than 

other parts of the lake, more commonly exhibits characteristics of a eutrophic lake (turbid and highly productive).

The food web of the lake is sufficiently productive 

to support a substantial fish community. Northern pike 

(Esox lucius) are abundant, and muskellunge (Esox 

masquinongy), walleye (Stizostedion vitreum), smallmouth bass (Micropterus dolomieui), cisco (Coregonus 

artedii), and a few species of panfish (Percidae spp.) are 

common (Water Resources Management Program, University Of Wisconsin-Madison, 1991). Many species of 

aquatic plants (macrophytes) inhabit the lake. Macrophytes that are most common in Musky Bay include 

Canada waterweed (Elodea canadensis), fern pondweed (Potamogeton robbinsii), coontail (Ceratophyllum demersum), muskgrass (Chara spp.), water 

buttercup (Ranunculus spp.), water milfoil (Myriophyllum spp.), and wild celery (Vallisneria americana) (Mr. 

Daniel Tyrolt, Lac Courte Oreilles Tribe Conservation 

Dept., written commun., 2001).

The climate in the vicinity of Lac Courte Oreilles is 

characterized by long, snowy winters and relatively 

warm, humid summers. The average annual precipitation is 775 mm, two-thirds of which falls between May 

and September inclusive (Water Resources Management Program, University Of Wisconsin-Madison, 

1991). 

Soils in the northern part of Sawyer County are 

generally better drained than those in the southern part. 

Common surficial material in the watershed of Lac 

Courte Oreilles includes loose, unconsolidated loamy or 

silty soils over glacial till or sand and gravel outwash. 

Typical depth to bedrock is 15-30 m (Water Resources 

Management Program, University Of Wisconsin-Madison, 1991). 

Non-lake land cover in the immediate drainage 

basin of Lac Courte Oreilles is mainly forest (72 percent) (Wisconsin Department of Natural Resources, 

1998; fig. 3). Grassland accounts for 11 percent. Only 

10 percent of the land cover is wetland. Cropland 

(mainly rotational crops of alfalfa and corn) accounts 

for 7 percent and is mainly west of Lac Courte Oreilles. 

Drainage from the cropland area to the western side of 

Lac Courte Oreilles is not well developed (no streams 

shown on U.S. Geological Survey 7.5-minute topographic maps, fig. 1). Barren, shrub, and urban land 

altogether make up less than 1 percent of the land cover.

Sources of phosphorus to Lac Courte Oreilles and 

Musky Bay include tributary inputs, overland flow, and 

atmospheric deposition (Barr Engineering, 1998). 

Based on lake monitoring data and modeling, the major 

sources of phosphorus to Musky Bay are cranberry bogs 

(44 percent), atmospheric deposition (17 percent), forests and wetlands (25 percent), shoreline development 

(8 percent) and agriculture (6 percent).

The Indian Reservation of the Lac Courte Oreilles 

Tribe includes the eastern part of the Lac Courte 

Oreilles watershed and occupies an area of 30,945 ha in 

central and western Sawyer County (fig. 1). The reservation is sparsely populated with approximately 2,400 

inhabitants. In addition to Lac Courte Oreilles, which 

lies partly within the reservation and partly to the west 

of it, numerous other lakes and rivers are in and around 

the reservation (water covers more than 4,200 ha of the 

reservation). 

Land-Use History

Cranberry Farming

Cranberry agriculture has been an important economic activity in northwest Wisconsin for the past 

six decades. Practices associated with cranberry farming are potential sources of nutrients, trace elements, 

synthetic organic compounds, and sediments to Lac 

Courte Oreilles. Cranberry bogs are constructed on wetlands. Fields are typically flooded with lake water several times a year, and water is discharged back to the 

lake. Cranberry crops may be treated with various fertil-
8 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 3. Land cover in the Lac Courte Oreilles watershed.

Urban

Agriculture (crop)

Cranberry bog

Grassland

Forest

Water

Wetland

Barren and shrub land

Land cover

Streams

Lac Courte Oreilles

direct drainage basin

EXPLANATION

Other features

Land use data source: WISCLAND Land Cover, 

1992—93 (Lillesand and others, 1998)

MILES

0 KILOMETERS

0 1

1 2

2

Windigo 

Lake

 

Grindstone Lake

Sand Lake

Whitefish Lake

Couderay

River

Devils 

Lake

Ashegon 

Lake

Durphee

 Lake

Musky Bay

Chicago

Bay

Northeastern Bay

Stucky 

Bay

Lac Courte Oreilles

Billy Boy Flowage Billy Boy Flowage

Little 

Lac Courte 

Oreilles

Squaw Creek

Ghost Creek

Squaw Creek

Ghost Creek

Base from U.S Geological

Survey 1:24,000 digital data 
DESCRIPTION OF STUDY AREA 9

izers and pesticides. Fertilizer is used largely to enrich 

the supply of phosphorus in the soil (Roper and Planer, 

1996). Statewide, phosphate fertilizers are commonly 

applied at a rate of about 50 kg P ha-1 on cranberry bogs 

(Schreiber, 1988). Approximately 22 pesticides are 

commonly used on cranberries, including naproprimide, norflurazon, dichlovenil, and 2,4-D (herbicides); 

carbaryl, diazinon, chlorpyrifos, and azinphos-methyl 

(insecticides); and the fungicide copper hydroxide 

(Mahr and others, 1998; Wisconsin Agricultural Statistics Service, 1996; Schreiber, 1988). Construction or 

expansion of beds requires removal of all surface vegetation, possibly affecting streamflow, sediment loads, 

and water quality in receiving waters (Schreiber, 1988). 

In a study of a Massachusetts cranberry bog, it was 

found both nitrogen and phosphorus may leach to 

receiving waters (Howes and Teal, 1995). Nutrients 

were released seasonally, coincident with flooding of 

the bog for harvest and winter frost protection. Nitrogen 

loading from the bog was about one-half of that from a 

nearby residential housing development, but phosphate 

loading was higher from the bog (Howes and Teal, 

1995).

Five cranberry bogs withdraw water from and discharge water to Lac Courte Oreilles, range in size from 

approximately 3 to 31 ha, and cover a total area of 84 ha 

(fig. 4). Bogs 1 and 4 are the largest of all the bogs, 

occupying 26 and 31 ha, respectively. Bog 1 is connected to Stucky Bay and bogs 4 and 5 are connected to 

Musky Bay and together occupy 41 ha. Bogs 1 and 5 

were created in 1939 (Randall Jonjak, cranberry farmer, 

oral commun., 2001). Bog 4 was created sometime 

between 1950 and 1962. The maximum expansion of 

bogs 1 and 4 occurred between 1950 and 1962 (64 and 

45 percent of total area, respectively). Bog 1 has 

remained the same size since 1962. Between 1980 and 

1998, 25 and 43 percent of the total area of bogs 4 and 

5 were added. Aerial application of fertilizer to bog 5 

was initiated in about 1995 (Dan Tyrolt, Lac Courte 

Oreilles Tribe, oral commun., 1999). 

Shoreline Development

In northern Wisconsin, cottages have been built 

along lakeshores typically since the first half of the 20th 

century. Many of the cottages on Lac Courte Oreilles 

were built between 1914 and 1944 (fig. 5), a period 

when tourism was heavily advertised for northern Wisconsin as an economic response to a decline in agricultural activities (Davis, 1996). The number of houses 

along the shoreline of Lac Courte Oreilles continued to 

grow during 1944–2001. However, since the mid1970s, there has been a trend to expand the size of existing cottages and build larger new homes. These larger 

houses occupy a greater surface area, increasing the 

impervious surface and potential land disturbance compared to initial cottage development. In addition, many 

cottages have been converted from seasonal to yearround use. Removal of native vegetation is more popular and the landscape is more disturbed and managed 

than during the initial cottage development. Increases of 

waste disposal (most homes use septic systems) and use 

of fertilizers and pesticides associated with this development also are potential sources of additional inputs to 

the lake ecosystem. 

Only a few studies have examined the effects of 

shoreline housing development on the nutrient levels 

of lakes. A paleolimnological study of lakes in southcentral Ontario found that most lakes have present-day 

phosphorus concentrations similar to predevelopment 

concentrations despite moderate cottage development 

(Hall and Smol, 1999). In a paleolimnological study of 

four Wisconsin lakes, initial cottage development had 

little effect on the lakes, but converting seasonal 

cottages to year-round homes caused increases in soil 

erosion (Garrison and Wakeman, 2000). Phosphorus 

deposition increased in all four lakes but the amount 

was dependent on alkalinity, with low-alkalinity lakes 

showing more phosphorus deposition to sediments than 

high-alkalinity lakes (Garrison and Wakeman, 2000).

The history of shoreline housing development on 

Lac Courte Oreilles was determined through the use of 

a 1914 Sawyer County Survey map, 1944 and 1971 historical USGS 7.5-minute topographic maps, and a 2001 

house survey conducted by the Lac Courte Oreilles tribe 

(table 1, fig. 5; Dan Tyrolt, Lac Courte Oreilles Conservation Dept., written commun., 2001). Therefore, housing development on the four Lac Courte Oreilles bays 

can be compared for the three periods: 1914–1944, 

1944–1971, and 1971–2001. In 1914, only a few houses 

were present on Stucky and Chicago bays, and no 

houses had been built on the shores of Musky or NE 

bays. By 1944, initial cottage development had begun 

on all bays, with the most growth on NE and Chicago 

bays. Development on Musky Bay occurred at a similar 

rate during 1944–71 and 1971–2001. The majority 

of growth on NE and Stucky bays occurred during 

1944–71. Chicago Bay had the most growth during 

1971–2001. Musky Bay’s shoreline housing density in 

2001 was about one-half or less of the housing density 
10 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 4. Map and graph showing expansion of cranberry bogs near Lac Courte Oreilles,1939 through 

1998. Data from 1943, 1946, 1950, 1962, 1992, and 1998 are based on aerial photographs. Data from

1971 are based on U.S. Geological Survey 7.5-minute topographic maps. Bogs 1 and 5 were 

constructed in 1939.

Bog 5

Bog 3

N

0

0

0.5 1 MILES

0.5

Durphee

Lake

0

5

10

15

20

25

30

35

Bog 1 Bog 2 Bog 3 Bog 4 Bog 5

CRANBERRY BOG SITE

AREA OF BOG, IN HECTARES

1939

1943

1950-62

1950

1946

1962

1962

1962

1946

1971

1950 1950

1971

1980

1998

1971-80

1998

1943-46

1950

1962

1939

1992

Bog 1

Bog 2

Bog 4

Whitefish Lake

Musky Bay

Stucky 

Bay

Lac Courte Oreilles

Chicago

Bay

1 KILOMETERS
DESCRIPTION OF STUDY AREA 11

Table 1. Density of houses along selected bays in Lac Courte Oreilles 

[Data for 1914 based on a 1914 Sawyer County Survey map. Data for 1944 and 1971 are based on USGS 15- and 7.5-minute topographic maps, 

respectively. Data for 2001 are based on a boat survey done by the Lac Courte Oreilles Conservation Dept. (Dan Tyrolt, Lac Courte Oreilles 

Conservation Dept., written commun., 2001)]

Bay

Approximate 

length of bay 

shoreline 

(kilometers)

Number of homes

Average housing density 

(number houses per kilometer of bay 

shoreline)

1914 1944 1971 2001 1914 1944 1971 2001

Musky 4.5 0 7 21 37 0 1.6 4.7 8.2

Northeastern 2.8 0 13 36 49 0 4.6 12.8 17.5

Stucky 2.1 1 3 22 28 .48 1.4 10.6 13.5

Chicago 3.5 3 22 45 75 .86 6.3 13.0 21.6

Figure 5. Shoreline development on four bays on Lac Courte Oreilles. Data for 1914 based on a 1914 Sawyer County 

Survey map. Data for 1944 and 1971 are based on USGS 15- and 7.5-minute topographic maps, respectively. Data for 

2001 are based on a boat survey by the Lac Courte Oreilles Conservation Department.

0

5

10

15

20

25

Musky Northeastern Stucky Chicago

BAY

HOUSING DENSITY, IN

NUMBER OF HOUSES PER KILOMETER 

1914 1914 1914 1914

1944

1944

1944

1944

1971

1971

1971

1971

2001

2001

2001

2001
12 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

for other Lac Courte Oreilles bays, primarily because 

Musky Bay is surrounded by low-lying wetlands that 

are less suitable for housing development than the other 

bays.

STUDY METHODS

Sediment Coring and Subsampling

Sediment cores were collected in 1999 from Musky 

and NE bays and other sites within Lac Courte Oreilles. 

The coring site on Musky Bay (MB-1) was on the southeast side of the bay near a cranberry-bog discharge point 

for surface-water runoff (fig.1). The second site selected 

for coring was in NE Bay, on the northeast side of Lac 

Courte Oreilles (LCO-1; fig. 1). Additional cores were 

collected from Musky Bay (one from the center (MB-2) 

and one from the northeast side (MB-3)), Stucky Bay 

(SB-1), and the center (deep basin) of the lake (LCO-2) 

(fig. 1, table 2). 

All cores were collected from an aluminum boat 

with a WDNR piston corer, except LCO-2, which was 

collected from the deepest basin of the lake with a 

USGS gravity corer. The piston corer is composed of a 

metal head, rubber pistons with steel nuts and bolts, and 

an 8.8-cm inside-diameter acrylic barrel. The gravity 

corer has a 6.4-cm inside-diameter acrylic barrel. 

Before coring in 1999, the corers were washed with 

low-phosphate detergent and rinsed with deionized 

water before the field sampling and were rinsed with 

copious amounts of lake water at the time of sampling. 

Each core was described briefly, and major changes in 

color, macrophyte content, water content, and texture 

were noted (table 3). All cores were vertically extruded 

in the field, and 1-cm or 2-cm subsamples were 

extracted from cores collected at sites MB-1, MB-3, 

LCO-1, LCO-2, and SB-1 (table 2). Only top and bottom intervals were extracted from LCO-2 and no samples were extracted from MB-2. After the field trip, all 

samples were frozen or freeze-dried, and archived at the 

USGS office in Middleton, Wis., and the WDNR office 

in Monona, Wis.

Two side-by-side cores were collected from sites 

MB-1, LCO-1, and SB-1 (table 2). Subsamples for 

minor and trace element, nutrient, and biogenic silica 

analyses were saved from the first side-by-side core and 

placed into clean plastic jars and chilled after collection. 

Subsamples for diatom, pollen, and radiometric analysis were saved from the second side-by-side core and 

placed into plastic bags. 

In August and September 2001, supplementary 

coring was done in Musky Bay, Stucky Bay, and NE 

Bay, as well as other nearby lakes including Sand Lake, 

Devils Lake, and Ashegon Lake. Cores from the Lac 

Courte Oreilles bays, Sand Lake, and Devils Lake were 

collected with a different piston corer. The piston corer 

was washed with low-phosphate detergent and rinsed 

with deionized water before the field sampling and 

stored in clean plastic bags. In the field, the corer was 

rinsed with copious amounts of lake water. The cores 

were vertically extruded, and the top 2 cm was subsampled and placed in plastic wide-mouth jars. Ashegon 

Lake was shallow enough to allow for wading, and 10 

samples of the top 2 cm of sediment were collected by 

use of a 2.5-cm Teflon tube that was cleaned in the same 

manner as the piston corer. These surficial-sediment 

samples were submitted for minor- and trace-element 

analysis.

In order to help determine potential sources for 

minor and trace elements, soils and fertilizer also were 

collected in August 2001 (table 4). Soils from two cranberry bogs were sampled: bog 1 near Stucky Bay and 

bog 5 near Musky Bay (fig. 4). At bog 1, seven cores 

from each of three beds were collected by use of a 

2.5-m Teflon tube and plastic spatula. The sampling 

equipment was washed with low-phosphate detergent 

and rinsed with copious amounts of deionized or tap 

water between bog sites. The cores from bog 1 penetrated to about 10 cm and contained a mix of sandy sediment associated with the root zone of cranberry plants 

(approximately 0–8 cm), as well as about 2 cm of peat 

from the pre-farm wetland soil beneath the sandy sediment. The 21 samples were composited into a single 

sample to represent soil conditions at each bog. The 

sample was homogenized and split, with one-half given 

to the farmers for private analysis. Seven cores were 

collected and composited from four cranberry beds in 

bog 5 in the same fashion as those at bog 1, except only 

the sandy sediment above the pre-farm peat was collected. Two fertilizer samples were collected from the 

farm at bog 1, one from a 13-13-13 mix applied at about 

110 kg ha-1 twice a year and a second sample from a 

high-phosphorus fertilizer from a natural phosphate 

source with a 0-46-0 mix applied for experimental spot 

application at about 1 bag (23 kg) per year for all of 

bog 1. Seven cores of the top 2 cm of a wetland soil 

(WET-1) and a shoreline residence on the southeastern 

side of Musky Bay (LEV-1) were collected and com-
STUDY METHODS 13

Table 2. Description of cores collected by U.S. Geological Survey (USGS) and Wisconsin Department of Natural Resources 

(WDNR) from Lac Courte Oreilles, October 1999

[WDNR analyzed for diatoms, water weight, loss on ignition, pollen, sedimentation rate; USGS analyzed for biogenic silica, carbon, nitrogen, geochemistry; 

nd, not determined; m, meter; cm, centimeter; do, ditto]

Site

identification

code

Latitude/longitude Location 

description

Water 

depth 

(m)

Penetration

(m)

Recovery 

(m)

Sub-sampling 

increments

Sample

analyses

MB-1A 45°52'35"/91°27'14" Musky Bay, 

southeast 

corner, 

100 m from 

cranberry 

farm outlet

1.0 1.7 1.3 0–50, 1 cm;

50–100, 2 cm;

100–128, 4 cm

USGS, 3 samples for radiometric dating, 

12 samples 

for diatom 

analysis

MB-1B do do do 1.5 1.5 0–50, 1 cm;

50–100, 2 cm;

100–148, 4 cm

WDNR

MB-2 45°52'34"/91°28'05" Musky Bay, 

center

1.27 nd 1.38 none None

MB-3 45°52'48"/91°27'30" Musky Bay, 

northeast 

side

.90 nd 1.55 0–100, 2 cm Pollen analysis; 

1 geochemistry sample 

from 0–2 cm; 

diatoms and 

pollen

LCO-1A 45°55'46"/91°22'39" Northeastern 

Bay

2.2 nd 1.18 0–50, 1 cm USGS

LCO-1B do do do 1.19 .91 0–50, 1 cm WDNR

LCO-2 45°53'44"/91°23'55" Center of lake 26 nd .41 top and bottom 

1 cm

Diatom analyses 

only

SB-1A 45°54'22"/91°28'44" Stucky Bay, 

150 m from 

cranberry 

farm outlet

2.15 1.05 .930 0–50, 1 cm;

50–60, 2 cm

None

SB-1B do do 2.10 1.04 .838 0–50, 1 cm;

50–60, 2 cm

2 geochemistry 

samples from 

0–1 and 1–2 

cm
14 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table 3. Brief lithologic description of selected cores collected by U.S. Geological Survey and Wisconsin 

Department of Natural Resources from Lac Courte Oreilles in October 1999

[Depths not corrected for recovery ratios; cm, centimeter]

Identification 

code

Depth

(cm) Sediment description

MB-1B 0−70 Macrophyte-rich

70–84 Decrease in macrophytes, more dense

84−148 Increase in macrophytes

140−148 More dense, increase in blade-like leaves

MB-2 0−25 Organic muck

25−138 Gyttja, plant fragments

MB-3 0−50 Organic muck, dark

50−155 Olive gyttja with abundant yellowish plant fragments

LCO-1A 0−14 Dark organic-rich muck

14−20 Olive organic-rich muck, occasional sand grains

20 Increase in density, almost peatlike with increase in fibrous content

20−50 Olive, dense, peatlike, occasional sand grains

LCO-1B 0−15 Dark organic-rich muck

15−20 Olive organic-rich muck, occasional sand grains

20 Increase in density, almost peatlike, high in fibrous content

20−50 Olive, dense, peatlike, occasional sand grains

LCO-2 0−.5 Black muck

.5−45 Dark gray sediment

SB-1A 0−~11 Dark organic muck, high water content

11−14 Olive organic muck, high water content

14 Increase in density and large plant fragments

14−49 Olive, more dense muck with abundant plant fragments and rootlets 

49 Change to more granular texture, increase in density

49−60 Olive, granular, peatlike, less plant fragments

SB-1B 0−11 Dark organic muck, high water content

11−14 Olive organic muck, high water content

14 Increase in density and large plant fragments

14−63 Olive, more dense, muck with abundant plant fragments and rootlets

63 Change to more granular texture, increase in density

63−66 Olive, granular, peatlike, smaller plant fragments
STUDY METHODS 15

Table 4. Description of cores collected by USGS from Lac Courte Oreilles and nearby lakes, soils, fertilizer, and wetland, 

August 2001

[m, meters; cm, centimeters; lb, pound; na, no data; Samples submitted for geochemical analyses only.]

Site

identification

code

Latitude/longitude Location description

Water 

depth 

(m)

Sample type

Subsampling

increments

(cm)

MB-4 45°52'35"/91°27'14" Musky Bay, southeast corner, 

150 m from bog 5, same location as MB-1

1.0 Lake sediment, organic,

macrophyte-rich

0−2

MB-5 45°52'23"/91°28'29" Musky Bay, southwest corner, 

150 m from bog 4

1.0 Lake sediment, organic,

macrophyte-rich

0−2

SB-2 45°54'25"/91°28'43" Stucky Bay, 150 m from bog 1, 

same location as SB-1

1.2 Lake sediment, organic,

macrophyte-rich

0−2

LCO-3 45°55'46"/91°22'42" Northeastern Bay 2.0 Lake sediment, organic,

macrophyte-rich

0−2

SAN-1 45°51'29"/91°29'25" Sand Lake, northern shore 1.5 Lake sediment, sandy,

macrophyte-rich

0−2

DEV-1 45°50'30"/91°20'04" Devils Lake, northern shore .7 Lake sediment, organic,

macrophyte-rich

0−2

ASH-1 45°51'00"/91°18'23" Ashegon Lake, northern shore .9 Lake sediment, mix of sand 

and organics,

macrophyte-rich

0−2

WET-1 45°56'01"/91°26'35" Remote wetland .15 Soil from wetland, abundant plant fragments and 

roots

0−2

LEV-1 45°52'34"/91°27'07" Shoreline residence na Soil from residence next to 

cranberry farm, mix of 

sand, organic matter, and 

grass roots

0−2

JON-1 45°54'22"/91°27'59" Bog 1 na Soil from cranberry farm, 

mix of sand and peat

0−10

ZAW-1 45°52'24"/91°27'07" Bog 5 na Soil from cranberry farm, 

mainly sand with minor 

amounts of cranberry 

plant detritus

0−8

JON-2 na Bog 1 na Fertilizer 13-13-13 used at 

110 kg ha-1, twice yearly

na

JON-3 na Bog 1 na Fertilizer 0-46-0, experimental spot applicationna
16 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

posited for each site for comparison to cranberry-bog 

soils (table 4). 

Up to 23 intervals from Musky Bay cores MB-1A 

and MB-1B and 15 intervals from NE Bay cores LCO1A and LCO-1B were selected for analysis of minor and 

trace elements, fossils, and nutrients (table 5). Several 

intervals from Musky Bay core MB-3 were analyzed for 

water content, organic material, diatoms, and pollen. 

Additional samples were run for water content, organic 

material, and minor and trace elements from the top 

2 cm of cores from Musky Bay, NE Bay, and Stucky 

Bay; and nearby lakes including Sand Lake, Devils 

Lake, and Ashegon Lake. Four soil samples were analyzed for the same constituents. Two fertilizer samples 

also were analyzed for minor and trace elements. In 

addition to the increments listed in table 5, other increments from MB-1, MB-3, LCO-1, and SB-1 were analyzed for water content and organic material. Results for 

these additional analyses are available through the 

WDNR, Monona, Wis.

Physical Characteristics and Organic 

Content

Physical characteristics of cores measured included 

water weight percent, organic content, and particle size 

(table 5). Water weight percent and organic content for 

October 1999 samples were analyzed at the WDNR, 

Monona, Wis., and August 2001 samples were analyzed 

at the USGS, Middleton, Wis. Water weight percent was 

measured by use of standard American Society for Testing and Materials Procedure D2216-92, except that 

sample sizes were less than 20 g wet weight due to the 

small sample size. Percentage dry weight was determined by measuring weight loss after 24 hours at 

105°C. Organic content was determined by weight loss 

after ashing or ignition (LOI) at 550°C for 1 hour (Dean, 

1974). Dry bulk density was determined by the WDNR 

for the October 1999 samples by use of a known volume 

of sediment for determining water weight percent. 

Thus, dry mass per unit of wet volume of sediment 

could be calculated. Dry bulk density was calculated by 

use of the formula:

ρ = (D(2.5Ix + 1.6Cx ))/(D + (1-D) (2.5Ix + 1.6Cx)),(1)

where ρ is dry bulk density (g cm-3), x is depth in the 

core, D is the proportion dry weight of unit wet volume, I is inorganic proportion of dry material (assuming a density of 2.5 g cm-3), and C is organic 

proportion of dry material (assuming a density of 

1.6 g cm-3). Porosity (P), in percent, was calculated by 

use of the formula:

P = (1 - (ρ/Ds)) * 100, (2)

where ρ is dry bulk density (g cm-3), Ds is sediment 

density (assumed to be 2.5 g cm-3), and water density is 

assumed to be 1.0 g cm-3.

Five samples from cores collected in August 2001 

were submitted for particle-size analysis at the USGS 

sediment laboratory in Iowa City, Iowa. These samples 

were determined to have a sand component by hand texturing. Sand/fine breaks were determined for samples 

from cranberry bog soils (JON-1-1 and ZAW-1-1), NE 

Bay (LCO-3), Sand Lake, and Ashegon Lake. 

Radiometric Dating and Sedimentation Rates

Samples from cores MB-1 and LCO-1 were submitted to the Wisconsin State Laboratory of Hygiene, 

Madison, Wis., for radiometric analysis. Activity concentrations of 210Pb, 226Ra, and 137Cs were determined 

from direct gamma counting by use of an ultra-lowbackground intrinsic germanium semiplanar detector 

coupled to a multichannel analyzer (Schelske and others, 1994). Detector efficiency was determined as a 

function of both sample geometry and sample weight. 

Samples were freeze-dried, and most plant fragments 

were removed before analysis.

The 210Pb dating technique is based on the escape 

of 222Rn from the Earth and the subsequent decay of 

this radioactive gas into 210Pb. Thus, 210Pb is a naturally 

occurring radionuclide that enters the lake primarily 

through precipitation and dry atmospheric deposition. 

This technique is most suitable for dating sediment 

deposited during the last 150 years because the half-life 

of 210Pb is 22.26 years (Olsson, 1986). 

137Cs was first detected in 1945, and in 1952 the 

first increase in atmospheric fallout occurred in the 

Northern Hemisphere, corresponding to increased 

nuclear weapons testing (Krishnaswami and Lal, 1978; 

Anderson and others, 1987). In 1960 a minimum 

occurred, followed by a maximum in 1963. With the 

signing of the atmospheric nuclear test ban treaty, atmospheric contributions have dropped off substantially. A 
Physical Characteristics and Organic Content 17

Table 5. Summary of laboratory analyses performed on two cores from Musky Bay (MB-1 and MB-3) and one core from 

Northeastern Bay (LCO-1) collected in October 1999

[Two side-by-side cores were collected from MB-1 and LCO-1. Cores MB-1A and LCO-1A were sub-sampled for geochemistry, biogenic silica, and total 

organic carbon and nitrogen by the U.S. Geological Survey. Cores MB-1B and LCO-1B were sub-sampled for radiometric dating, diatoms, and pollen by the 

Wisconsin Department of Natural Resources. Some intervals from both cores were analyzed for radiometric dating and diatoms to confirm similarity between 

the side-by-side cores. TE, trace and minor elements; OC, total organic carbon; N, total nitrogen; cm, centimeter.]

Interval 

(cm)

Water and 

organic 

content

TE Biogenic

silica

OC 

and 

N

Dating Diatoms Pollen Remarks/quality assurance

Musky Bay, Core MB-1A

0–2 x x x 0–2 cm combined

2–3 xx x

3–4 x

4–5 xx x

5–6 x

6–7 x x x

7–8 x

8–9 x

9–10 xx x

12–13 x x x

15–16 x x x Biogenic silica, OC/N duplicate

18–19 x x x

21–22 x x x

24–25 x x x

26–27 x Dating done on both cores

27–28 x x x

30–31 x x x Biogenic silica, OC/N duplicate

33–34 x x x TE duplicate

36–37 x x x

40–41 x x x TE duplicate

44–45 x Dating done on both cores

45–46 x x x Biogenic silica, OC/N duplicate

50–52 x x x

60–62 x x x

70–72 x x x TE duplicate

84–86 x x x

Musky Bay, Core MB-1B

0–2 x 0–2 cm combined

0–1 x x

1–2 x

2–3 x

4–5 x

5–6 x

6–7 x

8–9 x

8–10 x x

10–11 x x

11–12 x

12–13 x

12–14 x

14–15 x

14–16 x
18 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Musky Bay, Core MB-1B

15–16 x x

16–17 x

16–18 x x

18–19 x Water, organic content duplicate

20–21 x x

20–23 x x

21–22 x

22–23 x

24–25 x

24–26 x

26–27 x x Dating done on both cores

28–29 x

30–31 x x x

32–33 x

33–34 x

34–35 x

36–37 x x Water, organic content duplicate

38–39 x

40–41 x x x

41–42 x

42–43 x

43–44 x

44–45 x x Dating done on both cores

45–46 x

46–47 x

48–49 x

50–52 x x x

54–56 x x

58–60 x

60–62 x x

62–64 x x

64–66 x x x

66–68 x x Water, organic content duplicate

70–72 x x x

74–76 x

78–80 x Water, organic content duplicate

80–82 x x

82–84 x

84–86 x

86–88 x

90–92 x x

Table 5. Summary of laboratory analyses performed on two cores from Musky Bay (MB-1 and MB-3) and one core from 

Northeastern Bay (LCO-1) collected in October 1999—Continued

[Two side-by-side cores were collected from MB-1 and LCO-1. Cores MB-1A and LCO-1A were sub-sampled for geochemistry, biogenic silica, and total 

organic carbon and nitrogen by the U.S. Geological Survey. Cores MB-1B and LCO-1B were sub-sampled for radiometric dating, diatoms, and pollen by the 

Wisconsin Department of Natural Resources. Some intervals from both cores were analyzed for radiometric dating and diatoms to confirm similarity between 

the side-by-side cores. TE, trace and minor elements; OC, total organic carbon; N, total nitrogen; cm, centimeter.]

Interval 

(cm)

Water and 

organic 

content

TE Biogenic

silica

OC 

and 

N

Dating Diatoms Pollen Remarks/quality assurance
Physical Characteristics and Organic Content 19

Musky Bay, Core MB-3

0–2 x x

2–4 x

4–6 x x

8–10 x

10–12 x x

12–14 x

14–16 x

16–18 x

20–22 x x x

24–26 x x

28–30 x

30–32 x x

32–34 x

34–36 x

36–38 x Water, organic content duplicate

40–42 x x x

44–46 x x

48–50 x

50–52 x x

52–54 x

54–56 x

56–58 x

58–60 x x

60–62 x x

64–66 x x

68–70 x

70–72 x x

72–74 x

76–78 x Water, organic content duplicate

80–82 x x

Northeastern Bay, Core LCO-1A

0–1 x x x

2–3 xx x

4–5 xx x

6–7 xx x

8–9 x x x OC/N duplicate 

10–11 x x x Biogenic silica duplicate

12–13 x x x TE duplicate 

14–15 x x x

16–17 x x x

18–19 x x x OC/N duplicate 

Table 5. Summary of laboratory analyses performed on two cores from Musky Bay (MB-1 and MB-3) and one core from 

Northeastern Bay (LCO-1) collected in October 1999—Continued

[Two side-by-side cores were collected from MB-1 and LCO-1. Cores MB-1A and LCO-1A were sub-sampled for geochemistry, biogenic silica, and total 

organic carbon and nitrogen by the U.S. Geological Survey. Cores MB-1B and LCO-1B were sub-sampled for radiometric dating, diatoms, and pollen by the 

Wisconsin Department of Natural Resources. Some intervals from both cores were analyzed for radiometric dating and diatoms to confirm similarity between 

the side-by-side cores. TE, trace and minor elements; OC, total organic carbon; N, total nitrogen; cm, centimeter.]

Interval 

(cm)

Water and 

organic 

content

TE Biogenic

silica

OC 

and 

N

Dating Diatoms Pollen Remarks/quality assurance
20 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Northeastern Bay, Core LCO-1A (cont.)

20–21 x x x Biogenic silica duplicate

22–23 x x x TE duplicate 

24–25 x x x

26–27 x x x

28–29 x x x

Northeastern Bay, Core LCO-1B

0–1 x x x

2–3 x x

4–5 x x

6–7 x x

8–9 x x

10–11 x x x

12–13 x x

14–15 x x

16–17 x x x

18–19 x

20–21 x

22–23 x

24–25 x x

26–27 x

28–29 x

30–31 x

32–33 x

34–35 x

36–37 x

38–39 x Water, organic content duplicate

40–41 x x

Table 5. Summary of laboratory analyses performed on two cores from Musky Bay (MB-1 and MB-3) and one core from 

Northeastern Bay (LCO-1) collected in October 1999—Continued

[Two side-by-side cores were collected from MB-1 and LCO-1. Cores MB-1A and LCO-1A were sub-sampled for geochemistry, biogenic silica, and total 

organic carbon and nitrogen by the U.S. Geological Survey. Cores MB-1B and LCO-1B were sub-sampled for radiometric dating, diatoms, and pollen by the 

Wisconsin Department of Natural Resources. Some intervals from both cores were analyzed for radiometric dating and diatoms to confirm similarity between 

the side-by-side cores. TE, trace and minor elements; OC, total organic carbon; N, total nitrogen; cm, centimeter.]

Interval 

(cm)

Water and 

organic 

content

TE Biogenic

silica

OC 

and 

N

Dating Diatoms Pollen Remarks/quality assurance
Physical Characteristics and Organic Content 21

date of 1963 was assigned to the sample with the highest 

137Cs activity, and average mass and linear sedimentation rates were determined for the years 1963 through 

1999.8 (time of core collection). The linear sedimentation rate was calculated as the depth (in centimeters) to 

the peak, divided by the elapsed time between 1963 and 

1999.8 (time of core collection). The same post-1963 

sedimentation rate was also applied to downcore intervals.

Sedimentation rates were also calculated by use of 

two popular 210Pb models: (1) the constant initial concentration (CIC) model (Goldberg, 1963; Krishnaswami and others, 1971; and Robbins, 1978), and 

(2) the constant rate of supply (CRS) model (Appleby 

and Oldfield, 1978; Robbins, 1978; Binford, 1990). The 

CIC model is somewhat simpler than the CRS model 

and has, as its central assumption, that the amount of 

unsupported 210Pb activity in the uppermost sediment 

layer is constant through time (Goldberg, 1963; Robbins, 1978). This assumption requires that any change in 

the sedimentation rate be matched by a similar change 

in 210Pb inventory at the sediment/water interface. The 

210Pb activity exhibits log-linear decreases with depth 

(as is the case for much of the Musky Bay core). If the 

sedimentation rate increases because of eutrophication, 

the 210Pb is diluted, and the CIC model cannot be used. 

A 1-cm error in the estimate of mixing depth can result 

in dates as much as 20–30 percent in error (Binford, 

1990; Blais and others, 1995). Alternatively, the central 

assumption for the CRS model is that the flux of 210Pb 

to the uppermost sediment layer remains constant 

through time. Any change in sedimentation rate will be 

reflected proportionately in a dilution of concentration 

of the 210Pb activity. The CRS model requires that the 

total 210Pb inventory be measured downcore to background (supported) 210Pb concentrations. Unsupported 

210Pb activities for both models were estimated by subtracting the average 226Ra activity (0.22 pCi g-1) for all 

sampled intervals in the core from total 210Pb activity. 

For the CIC model, the age (t) of any interval (z) 

expressed as cumulative mass (g cm–2) is calculated as 

follows:

tz = λ-1 ln(C0 Cz

-1), (3)

where tz is the age (years) of sediment at cumulative 

mass, z (g cm–2); λ is the decay constant for 210Pb 

(0.03114 y-1); C0 is the unsupported 210Pb activity at 

the sediment/water interface (pCi g-1); and Cz is the 

unsupported 210Pb activity at cumulative mass, z 

(pCi g-1). The mass sedimentation rate (g cm-2 y-1) 

was calculated by dividing the 210Pb decay constant 

(0.03114 y-1) by the absolute value of the slope of the 

best-fit line for parts of the core that exhibited log-linear decreases with cumulative mass. For core MB-1 the 

CIC model was used for the interval 8–45 cm.

For the CRS model, the age (t) of any interval (z) is 

calculated as follows:

tz = λ-1 ln(A0 Az

-1), (4)

where A0 is the total, integrated, unsupported (excess) 

210Pb activity in the core (pCi g-1) and Az is the integrated activity of unsupported (excess) 210Pb below 

depth z. Mass sedimentation rates (ωz) can be calculated explicitly as:

ωz = λ·(Az Cz

-1). (5)

Bioturbation (mixing due to biological activity), 

erosion, and redeposition are common problems with 

any radiometric technique. Studies that have used both 

CIC and CRS models have shown mixed results. The 

CIC model has been used in many studies of sedimentation in the deep basins of the Great Lakes (for example, 

Evans and others, 1981), where downcore changes in 

sedimentation rates are small, and thus the assumption 

of the CIC model is probably reasonable. The CRS 

method sometimes is preferred if 210Pb activity is 

diluted by changes in sedimentation rates (Binford, 

1990). Benoit and Rozan (2001) compared the CIC and 

CRS model results to 137Cs peaks and found that sedimentation rates determined from 137Cs peaks were 

higher for two of the three lakes studied than both the 

CRS- and CIC-modeled sedimentation rates. Blais and 

others (1995) attributed disagreement between the 

210Pb and 137Cs dates to 137Cs migration; they also 

found that these models agreed reasonably well when 

the bulk sedimentation rate had not changed substantially in recent years. When sedimentation rates had 

changed in recent years, the dates from the CIC model 

consistently were more recent than independent date 

markers, such as the rise in ragweed and stable lead or 

the 137Cs peak. Remobilization of 137Cs is rare in clayrich deposits but may be a problem under anaerobic 
22 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

conditions with organic-rich sediment (Evans and 

others, 1983; Crickmore and others, 1990).

A piecewise CRS model was also constructed by 

calculating the 210Pb flux for independently dated intervals determined by other chronostratigraphic markers 

(Appleby, 1998). Independently dated intervals for core 

MB-1 included 137Cs peak at 30–31 cm (1963), stable 

Pb peak at 24–26 cm (1976), and organic content 

changes at 80–82 cm representing European settlement 

and beginning of clear-cut logging era (1880). In addition, the 137Cs model was assumed to be accurate downcore to 45 cm (1936) because of the good fit of the CIC 

regression line between 210Pb activity and cumulative 

mass from 8 to 45 cm (fig. 9). The CRS and CIC modeled date for 7–8 cm (1996) was also assumed to be 

accurate. These five dates were used to adjust the CRS 

modeled sedimentation rates by use of methods 

described by Appleby (1998) where:

P = (λ (!A))/(e-λt1-e-λt2), (6)

and P is 210Pb flux in pCi cm-2 y-1, !A is the 210Pb 

inventory between depths of x1 and x2 with known 

dates of t1 and t2. 

Total Organic Carbon and Nitrogen

Total organic carbon and total nitrogen concentrations were determined simultaneously on freeze-dried 

subsamples with a Leco 932 CHNS analyzer at the U.S. 

Geological Survey, Geologic Division Laboratory, 

Reston, Va. Organic carbon content was determined on 

the Leco after treatment of the samples with hydrochloric acid (HCl) to remove carbonates by means of an acid 

vapor method (Yamamuro and Kayanne, 1995; Orem 

and others, 1999). Preliminary analysis on samples pretreated with HCl indicated that virtually all carbon 

present was organic (not carbonate-related). Therefore, 

total carbon concentrations essentially represent total 

organic carbon concentrations. The Leco method is a 

high-temperature combustion method wherein solidphase carbon is quantitatively converted to carbon dioxide and nitrogen is initially converted to nitrogen oxides 

and then to nitrogen gas in a reduction furnace containing copper turnings. The carbon dioxide gas is quantified with a nondispersive infrared detector, and the 

nitrogen gas is quantified with a thermal conductivity 

detector. 

Minor and Trace Elements

Samples were analyzed for 43 minor and trace elements at the Geologic Division of the USGS Laboratory 

in Denver, Colo. Freeze-dried samples were completely 

digested on a hot plate using a mixture of hydrochloricnitric-perchloric-hydrofluoric acids and all elements 

except sulfur were analyzed by use of inductively coupled plasma-mass spectrometry (Briggs and Meier, 

1999). Sulfur was analyzed by methods describe in 

Jackson and others (1985) and Jackson and others 

(1987). Concentrations are given as micrograms per 

gram (μg g-1) dry weight (weight percent) for trace 

elements or percent dry weight for minor elements. 

Samples were not sieved before analyses, so they 

included plant fragments as well as mineral matter.

Biogenic Silica

Biogenic silica concentrations were analyzed at the 

USGS Laboratory, Guaynabo, Puerto Rico, by use of a 

modification of the wet alkaline digestion technique 

with correction for mineral silica (DeMaster, 1981). 

The method is specific for amorphous (hydrated) silica 

and is therefore a good proxy for the abundance of diatoms and other siliceous microfossils including chrysophyte cysts, sponge spicules, and phytoliths. Microscopic examination of sediment from the Musky Bay 

core revealed relatively few of these nondiatom siliceous organisms. Therefore, the biogenic silica concentrations were assumed to be largely associated with the 

diatom community. Briefly, freeze-dried sediment samples (about 20 mg) were digested in 1 percent (by 

weight) Na2CO3 at 85°C in 40-mL plastic centrifuge 

tubes for 4 hours. The tubes were floated in a water bath 

and were agitated approximately every 15 to 20 minutes 

during the entire digestion. Subsamples of the digestion 

solution were withdrawn hourly and analyzed by means 

of the molybdate blue spectrophotometric method. 

Standards and reagent blanks had matrices identical to 

that of the samples (1 percent Na2CO3, diluted 1:9 plus 

31.5 μL 6 N HCl to neutralize). Standards and reagent 

blanks were run daily, and reagent blanks were subtracted from all standards and samples. Plasticware was 

used exclusively to avoid silica contamination from 

glassware. 

The method relies on the fact that amorphous silica 

is solubilized more rapidly than mineral silica under 

these digestion conditions. A typical curve of silica con-
Physical Characteristics and Organic Content 23

centration as a function of extraction time indicates a 

rapid increase during the first hour corresponding to dissolution of virtually all amorphous (noncrystalline or 

biogenic) silica, followed by a gradual increase over 

time reflecting much slower mineral dissolution. The 

biogenic silica concentration is determined as the Yintercept using a best-fit linear regression of the sampling points over the period of gradual increase following the initial rapid increase. When virtually all silica in 

a sample is biogenic, the time points generally define a 

horizontal line. In this case, an average of all the time 

points is used as the biogenic silica concentration. This 

was the case for most of the samples from the Musky 

Bay and NE Bay cores. 

Diatoms

Samples for diatom analysis were cleaned with 

hydrogen peroxide and potassium dichromate (van der 

Werff, 1956). A portion of the diatom suspension was 

dried on a cover slip and samples were mounted in 

Naphrax (synthetic resin dissolved in toluene). Specimens were identified and counted by microscope under 

oil immersion objective (1,400X). In the upper four 

samples from core MB-1, at least 750 valves were 

counted from four or five slides from each depth. These 

additional counts were undertaken to ensure greater 

accuracy in the numbers of the diatom Fragilaria 

capucina. At all the other depths, two to five slides per 

depth were enumerated. In core MB-3, one to two slides 

were counted per depth until at least 250 valves were 

counted. In the NE Bay core, because of dating problems, less emphasis was placed on accuracy of the 

counts. In this core, counts were made until at least 170 

valves were enumerated. A known amount of glass 

microspheres was added to each sample following the 

procedure of Battarbee and Keen (1982). This allowed 

a determination of the concentration of diatom valves in 

the counted samples. 

In the MB-1 core, diatom biovolumes and surface 

areas were estimated by means of the program BIOVOL 

(v 2.1) (Kirschtel, 1996) and measurements obtained 

from a representative number of the common taxa. To 

substantiate that the variability in the biovolume profile 

was legitimate, the samples with the highest peaks were 

redigested and recounted; similar numbers were 

obtained. 

Common nationally and internationally recognized 

keys were used including those of Patrick and Reimer 

(1966, 1975), Camburn and others, (1984–86), Dodd 

(1987), and Krammer and Lange-Bertalot (1986, 1988, 

1991a, b). Diatom nomenclature is currently in a state of 

flux. For this study, we followed the checklist of the 

Laurentian Great Lakes of Stoermer and others (1999).

Pollen

Samples for pollen analysis were cleaned by use of 

the technique of Faegri and Iverson (1989). Samples 

were treated with KOH, HF, and acetolysis. A portion of 

the sample was mounted on a microscope slide with 

polyvinyllactophenol. The slides were examined until at 

least 100 terrestrial grains and spores had been counted. 

Keys used for identification were those of McAndrews 

and others (1973) and Moore and others (1991). Wild 

rice (Zizania palustris) was distinguished from other 

grasses from the size and texture of the pollen grains. 

Grass pollen from Musky Bay was compared with rice 

pollen found in Irving Lake, Wis. The latter lake currently has a large population of wild rice. Based upon 

comparison with pollen from Irving Lake rice in Musky 

Bay was assumed to have a size range of 27–33 μm 

(fig. 6) and a psilate (smooth) texture on the pollen grain 

surface. This agrees with McAndrews (1969) who 

found that wild rice pollen grains ranged in diameter 

from 25–32 μm. The mean diameter of the rice pollen in 

Irving Lake was 29.2 μm and 28.5 μm in Musky Bay. 

The mean length of the grain was 29.8 μm in Irving 

Lake and 31.6 μm in Musky Bay. The grains in both 

lakes had protruding annulate pores with a width of 

8–9 μm and height of 2.5 μm. The Musky Bay core also 

contained other grass pollen that was assumed to be 

other grasses. These grains did not have a smooth 

surface texture, but instead they had a wart-like (verrucate) texture and a smaller diameter (about 20–22 μm).

Quality Assurance

About 10 to 15 percent of the samples submitted to 

the various laboratories were replicate samples (sample 

splits). A comparison of the results for sample splits is 

given in table A10. Average percent difference (absolute difference of the two samples divided by the average of the two samples) was generally less than 

10 percent for most constituents. Some of the minorand trace-element data had higher percent differences, 

including Al (12 percent), Sb (23 percent), Be (34 per-
24 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 6. Comparison of the diameter of wild rice pollen grains from Irving lake, Wisconsin and Musky Bay, Lac Courte 

Oreilles, Wisconsin. Irving Lake has a large population of wild rice.

Photo of wild rice pollen grain 

from Musky Bay

0

5

10

15

20

27-28 28-29 30-31 31-32 32-33

GRAIN DIAMETER IN MICRONS

NUMBER

Musky Bay

0

2

4

6

8

10

27-28 28-29 30-31 31-32 32-33

GRAIN DIAMETER IN MICRONS

NUMBER

Irving Lake
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 25

cent), Cu (33 percent), Pb (18 percent), and Zn (16 percent). 

Each laboratory had quality-control measures that 

included comparisons to standards and standard reference materials, spikes, and duplicates. Quality-control 

measures for the USGS National Water Quality Laboratory in Denver, Colo., and the Geologic Division Laboratory are given in Pirkey and Glodt (1998) and 

Arborgast (1990), respectively. For total organic carbon 

and total nitrogen determinations, appropriate standards 

and blanks were run at the start of each day to check 

instrumental operation. Samples were run at least in 

duplicate, and the values were averaged. Standards and 

blanks were interspersed among the samples to account 

for instrumental drift and sample carryover in the calculation of concentration. 

For minor- and trace-element samples, a “blank” 

sediment sample composed of fine-grained abrasive 

quartz (150 μm) was run through both piston corers and 

subsampling equipment, and results are shown in table 

A4. Because of its abrasive characteristics, fine-grained 

quartz will tend to overestimate potential contamination 

compared to Musky Bay core sediments. A third blank 

sediment sample was submitted without exposing it to 

any coring equipment. For all three samples, only five 

elements were found in concentrations above the minimum reporting levels. The comparison of the three samples indicates that all samples contained similar 

concentrations of Al, Ba, and Li. These elements are 

assumed to be present in the original blank sample. The 

blank sample run through the piston corer used in 1999 

contained a Cd concentration of 1.2 μg/g (the minimum 

reporting level for Cd is 0.1 μg/g). The source for the Cd 

in the sampling equipment is not known. Potential 

sources include steel parts on the corer or contact of the 

corer with plastics that include Cd as a stabilizer. The 

blank sample run through the USGS piston corer contained an As concentration of 0.11 μg/g, slightly above 

the minimum reporting level of 0.1 μg/g.

As a check that the two side-by-side MB-1 cores 

collected at Musky Bay (MB-1A for nutrients, biogenic 

silica, and minor and trace elements; and MB-1B for 

radiometric dating, diatoms, and pollen) represented the 

same depositional history, additional samples of diatom 

community and radiometric activity were analyzed at 

selected depths from core MB-1A. Results were then 

compared to the same intervals in MB-1B. Diatoms 

were examined in at least two slides from each depth 

until at least 300 valves were encountered. A comparison only was made of the common taxa. Appendix A8 

lists the results of duplicate counts for the diatom concentration. 

HISTORICAL TRENDS FROM MUSKY BAY 

AND NORTHEASTERN BAY

Data for physical characteristics, nutrients, minor 

and trace elements, biogenic silica, diatoms, and pollen 

for all samples can be found in tables A1–A9. The following sections describe the trends in those characteristics and constituents and the possible causes for those 

trends.

Bulk Density and Organic Content

In general, sediment from Musky Bay cores MB-1 

and MB-3 had lower bulk density and higher organic 

content than sediment from NE Bay core LCO-1 

(fig. 7A and B, respectively). In core MB-1, bulk density was constant (except for a peak at about 80 cm 

defined by a single sample) from the bottom of the core 

until 45 cm (fig. 7A). A peak occurred from 45 to 40 cm 

with values approaching 0.07 g cm-3. Above 40 cm 

values slightly decreased from 0.04 to 0.03 g cm-3 at 

4 cm (fig. 7A). The top three depths (0–4 cm) had the 

lowest densities. In MB-3, the bulk density generally 

decreased from the bottom of the core to 50 cm 

(fig. 7A). Between about 50 to 40 cm, bulk density 

decreased sharply from 0.05 to 0.03 g cm-3. From 40 cm 

to 30 cm there was a peak in the values and then the bulk 

density was constant at 0.025 g cm-3 until above 10 cm 

when it was variable. 

Profiles from both Musky Bay cores suggest a 

change in sediment input or source at about 40–45 cm 

and the upper 10 cm. However, the differences in the 

profiles suggest some subtle differences in local sedimentation history. Increases in bulk density can be the 

result of drying out of sediment, episodic increases in 

the input of clastic material, change in organic matter 

input, or dredging. It is not known what caused the 

peaks in the Musky Bay cores. The sharp increase 

downcore in bulk density from 40–50 cm corresponds 

to the noted change in character of sediment of MB-3 at 

50 cm (table 3). Above 50 cm, core MB-3 contained 

dark, organic-rich muck but below 50 cm core MB-3 

contained olive gyttja with abundant yellow blade-like 

plant fragments. Thus, this interval may reflect a slight 

increase in water depth that affected the aquatic vegeta-
26 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

tion, possibly related to an increase in water level at the 

Billy Boy Dam when it was upgraded about 1936. In 

core MB-1 the peak in bulk density from about 40–

45 cm may reflect an episodic increase in the input of 

clastic material. Core MB-1 did not have an observable 

change in the character of the sediment at this interval 

as did core MB-3 (table 3). 

Differences in the profiles of organic content in 

cores MB-1 and MB-3 also reflect different sedimentation histories that were possibly affected by local conditions (fig. 7B). Organic content in core MB-1 decreased 

from 63 percent at 85 cm to near 50 percent at 40–42 cm 

and then ranged from 45–50 percent from there to the 

core top. In core MB-3, organic content was considerably lower in the bottom of the core with values at 40–

45 percent below 50 cm. Between 50 and near 40 cm 

the organic matter increased significantly from 50 to 

63 percent. In core MB-3, the organic matter in the 

upper 40 cm was higher compared with the same intervals in core MB-1 (fig. 7B). The lowest organic content 

in core MB-1 was measured between 40 and 25 cm, 

indicating a possible increase in clastic material input 

during this interval. The large shift in organic content at 

about 50 cm in core MB-3 supports the changes 

observed in the bulk density profile for core MB-3 and 

suggests a large scale disturbance at this interval.

In the NE Bay core, bulk density had very large 

peaks at about 44 and 16 cm (fig. 7A). The large peaks 

in the NE Bay core may reflect episodic inputs of clastic 

material, drying, dredging or dragging of the bottom, or 

changes in water level. The peaks in bulk density in the 

NE Bay core correspond to lows in organic content 

(fig. 7B). A change in the character of the sediment was 

also noted for the NE Bay core at about 15 cm (table 3). 

Above 15 cm, the sediment was described as dark, 

organic-rich muck, whereas below 15 cm, the sediment 

was described as olive organic-rich muck with occasional sand grains. This change in the description of the 

NE Bay core at 15 cm is similar to the change in 

description of the MB-3 core at 50 cm.

Sedimentation Rates

For Musky Bay, the total 210Pb and 137Cs profiles 

from the core MB-1B indicate that little postdepositional mixing has occurred in this core, except possibly 

in the top 8 cm (fig. 8A). The 137Cs profile exhibited a 

sharp peak at 30-31 cm. Radiometric activities for six 

intervals from core MB-1A (taken alongside MB-1B) 

compared well with radiometric activities from the 

same intervals for core MB-1B, consistent with the likelihood that the cores represent similar depositional histories (fig. 8A). The total 210Pb profile of core MB-1B 

is relatively smooth downcore to 45 cm, except for the 

sharp decrease in activity above 8 cm. A decrease in 

activity is typically an indication of higher sedimentation rate and more dilution of 210Pb inputs. Below 

45 cm, the total 210Pb profile flattens and includes an 

increase in activity from 55-65 cm, typically an indication of a lower sedimentation rate and less dilution of 

210Pb inputs. The 226Ra activities remained relatively 

uniform downcore, indicating that sources for sediment 

were similar over the period of record exhibited by the 

core. 

The radiometric profiles for the NE Bay core 

(LCO-1B) indicate that post-depositional mixing, erosion, or slug deposition occurred above 15 cm, and (or) 

that some major episodic event occurred below 15 cm, 

such as dredging (fig. 8B). Sharp breaks are evident in 

both the 210Pb and 137Cs profiles at this depth, and concentrations above this depth are relatively uniform. 

Slight increases in 210Pb and 137Cs activities in the NE 

Bay core above about 3 cm possibly indicate that the 

uppermost sediment layers have not been disturbed and 

that the mixing/erosion/deposition occurred a few 

decades ago. The disturbance problem with the NE Bay 

core severely limited its usefulness for comparison to 

the Musky Bay core, and further discussion of differences between the two cores in this report is limited to 

general comparison of recent and presettlement conditions. Sedimentation rates could not be calculated from 

this core.

Mass and linear sedimentation rates were calculated for the Musky Bay core (MB-1) from the CIC and 

CRS models and from the 137Cs peak, as listed in 

table 6. Also listed in table 6 are approximate dates for 

each sampled interval. Sedimentation rates for the CIC 

model of the Musky Bay core were based on leastsquares regression of the natural log of unsupported 

(excess) 210Pb for only the 8–45 cm interval because of 

changes in the slope of the profile above and below this 

interval (fig. 9). For the interval 8–45 cm, the CIC

model yielded an average sedimentation rate of about 

0.034 g cm-2 y-1 (0.97 cm y-1) while the CRS yielded 

an average sedimentation rate of 0.038 g cm-2 y-1

(1.12 cm y-1) (table 6). Above 8 cm, the CRS 

model yielded an increase in sedimentation rate 

(0.051 g cm-2 y-1; 2.25 cm y-1). Below 45 cm, the 

CRS model indicates that mass sedimentation rates 
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 27

Figure 7. (A) Bulk density and (B) organic content data from loss on ignition for cores collected 

from Musky Bay and Northeastern Bay, October 1999.

0

20

40

60

80

100

120

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

DRY BULK DENSITY, IN GRAMS PER CUBIC CENTIMETER

DEPTH, IN CENTIMETERS

Musky Bay, MB-1

Northeastern Bay, LCO-1

Musky Bay, MB-3

Musky Bay, MB-1, replicate

Northeastern Bay, LCO-1, replicate

Musky Bay, MB-3, replicate

EXPLANATION

Musky Bay, MB-1

Northeastern Bay, LCO-1

Musky Bay, MB-3

Musky Bay, MB-1, replicate

Northeastern Bay, LCO-1, replicate

Musky Bay, MB-3, replicate

EXPLANATION

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70

PERCENTAGE OF ORGANIC CONTENT

DEPTH, IN CENTIMETERS

A

B
28 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 8. Comparison of radiometric data for (A) Musky Bay core and (B) Northeastern Bay core

collected in October 199. Horizontal error bars represent one sigma counting uncertainties. 

A

B

0

5

10

15

20

25

30

35

0 5 10 15 20 25

ACTIVITY, IN PICOCURIES PER GRAM

DEPTH, IN CENTIMETERS

Total 210Pb activity, LCO-1B

137Cs activity, LCO-1B

226Ra activity, LCO-1B

EXPLANATION

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14 16 18

ACTIVITY, IN PICOCURIES PER GRAM

DEPTH, IN CENTIMETERS

Total 210Pb, MB-1B

137Cs, MB-1B

226Ra, MB-1B

Total 210Pb, MB-1A

137Cs, MB-1A

226Ra, MB-1A

EXPLANATION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 29

Table 6. Estimated average mass and linear sedimentation rates from the CRS model, adjusted CRS model, CIC m

activity for Musky Bay core MB-1, Lac Courte Oreilles, October 1999

[--, no data; g, gram; cm, centimeter; y, year; CIC, constant initial concentration model; CRS, constant rate of supply model]

Interval 

(cm)

Mass sedimentation rate

(g cm-2 y-1)

Linear sedimentation rate

(cm y-1)

Estimated 

(bottom of 

CRS Adj. CRS CIC 137Cs CRS Adj. CRS CIC 137Cs CRS Adj. CRS 

0–2 0.054 0.067 -- 0.023 3.56 4.00 -- 0.84 1999 1999 3–4 .045 .098 -- .023 2.20 1.12 -- .84 1998 1999 5–6 .050 .051 -- .023 1.95 1.16 -- .84 1997 1998 7–8 .050 .047 -- .023 1.89 .72 -- .84 1996 1997 8–10 .035 .035 0.034 .023 1.26 .41 0.97 .84 1995 1995 

12–14 .037 .025 .034 .023 1.34 1.39 .97 .84 1992 1991 14–16 .033 .023 .034 .023 1.21 .74 .97 .84 1990 1988 16–18 .034 .022 .034 .023 1.22 .33 .97 .84 1988 1986 20–23 .040 .025 .034 .023 1.35 1.16 .97 .84 1985 1980 24–26 .037 .023 .034 .023 1.21 1.97 .97 .84 1982 1976 26–27 .034 .014 .034 .023 1.10 .21 .97 .84 1981 1974 27–30 .036 .013 .034 .023 1.04 1.53 .97 .84 1978 1966 30–31 .029 .010 .034 .023 .87 .21 .97 .84 1977 1963 31–34 .039 .025 .034 .023 1.05 .66 .97 .84 1974 1959 36–37 .041 .025 .034 .023 1.09 .36 .97 .84 1972 1954 40–41 .038 .020 .034 .023 .77 .52 .97 .84 1966 1945 44–45 .048 .024 .034 .023 .87 .23 .97 .84 1962 1936 50–52 .029 .041 -- .023 .83 .85 -- .84 1953 1929 54–56 .033 .037 -- .023 .80 .21 -- .84 1948 1924 60–62 .022 .031 -- .023 .63 .15 -- .84 1939 1916 64–66 .007 .012 -- .023 .22 .28 -- .84 1921 1903 66–70 .019 .028 -- .023 .47 .64 -- .84 1912 1897 70–72 .023 .037 -- .023 .54 .03 -- .84 1908 1895 80–82 .012 .033 -- .023 .35 .14 -- .84 1880 1880 84–86 .003 .015 -- .023 .12 .00 -- .84 1846 1870 
30 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

decreased substantially to an average of 

0.019 g cm-2 y-1 from 45–82 cm (0.45 cm y-1).

The 137Cs peak indicates that the sedimentation 

rate from 0–31 cm is less than that estimated from the 

CRS and CIC models (table 6, fig. 10). Assuming little 

remobilization of 137Cs on the basis of the sharpness of 

the 137Cs peak, the sedimentation rate from 0 to 31 cm 

averaged 0.023 g cm-2 y-1 (0.84 cm y-1), indicating that 

the dates derived from the CRS and CIC models are too 

recent (table 6, fig. 10). At the interval 30–31 cm, the 

CRS and CIC models predicted years of about 1977 and 

1976, respectively, instead of 1963 (table 6, fig. 10A). 

The 137Cs-based sedimentation rate of 0.023 g cm-2 y-1 

was extrapolated to intervals below 31 cm (table 6). The 

first occurrence of detectable 137Cs in the profile is at 

about 40–41 cm (1946) corresponding well to the 

known timing of the beginning of recognizable 137Cs 

fallout from the atmosphere in 1951 or 1952 (Beck and 

others, 1990). The relative change in CRS-modeled sedimentation rates at about 45 cm (approximately 1936 

based on the 137Cs model) is thought to be possible, 

even though average CRS sedimentation rates are suspected to be too high. Other researchers have found disagreement between 137Cs and 210Pb dates in cores 

(e.g. Anderson and others, 1987; Appleby, 2000). One 

possible explanation is that any change in mass sedimentation rate, such as that indicated by the change in 

the slope of 210Pb activity versus cumulative mass (fig. 

9) above 45 cm, will likely violate the assumptions of 

both the CRS and CIC models. If the additional material 

deposited in the lake has any excess 210Pb, which is 

likely because it is derived from the land surface, then 

the rate of supply (flux) will be greater than prior to the 

disturbance. Furthermore, unless the additional material 

has the same initial 210Pb concentration as earlier 

deposited sediments, which is unlikely, then the CIC 

assumption will be violated. A similar inconsistency in 

137Cs and 210Pb age dates was encountered in a core 

from Lake Harriet in Minneapolis by Van Metre and 

others (2000). There, the date of the 137Cs peak estimated using the CRS model was 1978 and a change in 

sedimentation rate was suggested in about 1940. They 

adjusted the Lake Harriet 210Pb dates to more closely 

match the 137Cs dates by use of a ratio based on the difference in estimated mass accumulation rates from the 

top of the core to the 1964 horizon for the two methods. 

The resulting dates were corroborated by contaminant 

peaks (lead, DDT, and PCBs) and by changes in sedimentation rates and numerous major and trace elements 

in about 1920 coincident with initial urbanization of the 

Figure 9. Best-fit log-linear curve (regression line) for unsupported 210Pb activity used in the constant initial concentration model. 

Regression was done for 8–45 cm interval of MB-1B only.

y = -0.9133Ln(x) + 2.7232

R2 = 0.95

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1.0 10.0 100.0

UNSUPPORTED 210Pb ACTIVITY, 

IN PICOCURIES PER GRAM

CUMULATIVE MASS, IN GRAMS PER

 SQUARE CENTIMETER
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 31

Figure 10. Comparison of (A) dates and (B) sedimentation rates from the constant rate of supply

(CRS), adjusted CRS, 137Cs, and the constant initial concentration (CIC) models for Musky Bay core

MB-1.

A

B

1820

1840

1860

1880

1900

1920

1940

1960

1980

2000

2020

0.00 0.02 0.04 0.06 0.08 0.10 0.12

MASS SEDIMENTATION RATE, 

IN GRAMS PER SQUARE CENTIMETER PER YEAR

YEAR

CRS model

Adjusted CRS model

137Cs model

CIC model

EXPLANATION

0

10

20

30

40

50

60

70

80

90

100

1840 1860 1880 1900 1920 1940 1960 1980 2000

YEAR

DEPTH, IN CENTIMETERS

CRS model

Adjusted CRS model

137Cs model

CIC model

Stable Pb peak

137Cs peak

Assumed presettlement

EXPLANATION
32 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

watershed (Peter Van Metre, U.S. Geological Survey, 

written commun., 2002).

The stable Pb profile also provided supporting evidence that the 137Cs-based dates are reasonable. Stable 

Pb concentrations peaked at 24–25 cm (assumed to be 

about 1976), coincident with the peak in leaded gasoline 

use and subsequent banning of lead from gasoline 

(table A9, fig. 13C). The stable Pb peak at 24–25 cm in 

the Musky Bay core agrees within about 5 years of the 

137Cs date of 1970 for the bottom of the 24–26 cm interval. Subsurface peaks in Pb have been dated to this time 

period in other lakes (Gobeil and others, 1995; Callender and Van Metre, 1997; Siver and Wozniak, 2001).

Sedimentation rates and estimated dates for the 

adjusted CRS model (Appleby, 1998) are listed in 

table 6 and shown on figure 10. As stated early, the 

adjusted CRS model was constructed by calculating the 

210Pb flux for independently dated intervals determined 

by other chronostratigraphic markers, including the 

137Cs peak at 30–31 cm (1963), stable Pb peak at 

24–26 cm (1976), and organic content changes at 80–82 

cm representing European settlement and beginning of 

clear-cut logging era (1880). In addition, the 137Cs 

model was assumed to be accurate downcore to 45 cm 

(1936) based upon the good fit of the regression line for 

210Pb activity versus cumulative mass (fig. 9). The CRS 

and CIC modeled date for 7–8 cm (1996) was also 

assumed to be accurate. Mass sedimentation rates calculated with the adjusted CRS model do not show a 

decrease below 45 cm as observed with the original 

CRS model (fig. 10B). This would be consistent with a 

change in 210Pb flux above 45 cm. Both the original and 

adjusted CRS models show an increase in sedimentation rates above 8 cm.

The results from the CRS, CIC, and 137Cs models 

were considered together, and it was determined that the 

average sedimentation rate calculated from the 137Cs 

profile would be most useful for subsequent interpretations of the overall timing of historical changes in the 

nutrient, minor- and trace-element, diatom, and pollen 

profiles—especially given the timing of land-cover 

changes from the 1930s through 1990s in the local 

area surrounding Musky Bay. The 137Cs model may be 

off by about 12 years (1868 instead of 1880) at the 

80–82 cm interval thought to represent the beginning of 

European settlement. Although the original CRS-model 

dates are too recent, the model may have some limited 

usefulness for showing relative short-term changes in 

sedimentation rates in the profile, such as the change in 

sedimentation rate shown in both CRS models at the top 

of the core. Below 45 cm, the sedimentation rates from 

the adjusted and original CRS models conflict with each 

other, indicating that the decrease in sedimentation rate 

calculated in the original CRS model is suspect. Dates 

from 137Cs activity (table 6) are shown on subsequent 

graphs included in this report.

Nutrients

Concentration of total organic carbon, total nitrogen, total phosphorus, and total sulfur are shown for 

Musky and NE bay cores in figure 11A–D. These four 

elements are major components of the organic matter in 

the sediments, excluding oxygen and hydrogen. Concentrations of these four elements were always lower in 

the NE bay core than in the Musky Bay core, consistent 

with lower organic content in the NE Bay core than the 

Musky Bay core (fig. 7B). A major discontinuity is evident in the NE Bay profiles of all four elements at about 

20 cm (LCO-1A). This break corresponds to the break 

in the radiometric profiles from LCO-1B (side-by-side 

core from the same location) at 15 cm. This slight offset 

of breaks in profiles may be a reflection of different core 

recoveries for LCO-1A compared to LCO-1B (table 2).

In the Musky Bay core (MB-1), the concentration 

of organic carbon decreases from 25 percent over the 

top third of the core to a minimum of about 21 percent 

at about 30 cm depth and then increases to about 27 percent at the bottom of the core (fig. 11A). Profiles of 

nitrogen and phosphorus decrease somewhat exponentially downcore to about 28 cm (figs. 11B–C). Concentration ranges for nitrogen and phosphorus are generally 

one and two orders of magnitude lower, respectively, 

than that for organic carbon. These proportions are consistent with the remains of macrophytes and epiphytic 

algal detritus being a major component of the sediments. 

The increasing organic carbon (and to a lesser 

extent nitrogen) concentrations downcore below about 

28 cm (prior to circa 1965) in the Musky Bay core indicate a very different balance between input, burial and 

(or) decomposition rates compared to those occurring 

during the last few decades. The typical exponentiallike decrease with depth at top of the core is consistent 

with either steady-state organic matter decomposition 

or possibly increasing OC input and (or) burial rates in 

recent decades. In contrast, increasing concentrations 

with depth below about 28 cm (beginning of the twentieth century to about 1965) imply any or all of the fol-
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 33

Figure 11. Concentration profiles of (A) total organic carbon, (B) total nitrogen, (C) total phosphorus, and (D) total

sulfur in Musky Bay core MB-1A and Northeastern Bay core LCO-1A. Dates refer to Musky Bay profiles only.

A B

C D 0

10

20

30

40

50

60

70

80

90

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

TOTAL SULFUR CONCENTRATION, IN PERCENT

DEPTH, IN CENTIMETERS

0

10

20

30

40

50

60

70

80

90

Musky Bay

Northeastern Bay

10 12 14 16 18 20 22 24 26 28

DEPTH, IN CENTIMETERS

ESTIMATED YEAR OF DEPOSITION

TOTAL ORGANIC CARBON CONCENTRATION,

IN PERCENT

0

10

20

30

40

50

60

70

80

90

1 1.5 2 2.5 3 3.5 4

ESTIMATED YEAR OF DEPOSITION

TOTAL NITROGEN CONCENTRATION, IN PERCENT

DEPTH, IN CENTIMETERS

0

10

20

30

40

50

60

70

80

90

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

TOTAL PHOSPHORUS CONCENTRATION, IN PERCENT

DEPTH, IN CENTIMETERS

ESTIMATED YEAR OF DEPOSITION

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

Musky Bay

Northeastern Bay

Musky Bay

Northeastern Bay

Musky Bay

Northeastern Bay
34 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

lowing for this period of time: (1) decreasing organic 

carbon input and (or) burial rate; (2) increasing organic 

carbon recycling rate perhaps driven by input of more 

easily decomposable organic matter, specifically epiphytic algae; (3) increasing dilution with mineral sediments. The period leading up to 1965 is one of 

cranberry farm construction wherein bog 4 was created 

and reached 44 percent of its 1998 size and bog 5 

expanded an additional 14 percent of its 1998 size 

(fig. 4). Residential development was also occurring 

during this period though it is uncertain how much of 

the increase between about 1954 and 1971 occurred 

prior to 1965 (fig. 5, table 1).

In the Musky Bay core, the sulfur profile differed 

from organic carbon, nitrogen, and phosphorus profiles 

in that the sulfur profile increased downcore from 0 to 

15–16 cm instead of decreased (fig. 11D). Sulfur in 

surficial sediment from productive lakes is often 

dominated by organic forms with lesser amounts of 

pyritic sulfur, acid-volatile sulfur, elemental sulfur, and 

dissolved sulfate and sulfide (Wetzel, 1983 and 

references within). Given this, the sulfur profile might 

be expected to resemble the organic carbon and nitrogen 

profiles, which decrease below the sediment-water 

interface. Either organically bound sulfur is 

preferentially lost compared to organic carbon and 

nitrogen or inorganic sulfur species must be 

quantitatively significant. A “rotten egg” odor was 

detected throughout the entire core, implying sulfate 

reduction as a major organic matter decomposition 

pathway. With sulfide in excess, all iron would 

precipitate as monosulfides and pyrite. The remaining 

sulfide would diffuse upward and downward and would 

be oxidized to sulfate at or within millimeters of the 

sediment-water interface. Sulfate that is not reduced 

again during organic-matter decomposition can escape 

to the overlying water. The subsurface peak at ~20 cm 

may represent a diagenetic zone of maximal sulfide 

mineral precipitation. If so, the total sulfur profile 

records diagenetic features more than it does a true 

input and burial history.

It is possible that nutrient and certain minor- and 

trace-element profiles reflect postdepositional decomposition and remobilization and not true inputs. For the 

Musky Bay core, two factors must be considered when 

interpreting elemental accumulation rates as being 

either true input histories or subject to postdepositional 

migration: the presence of seasonal macrophyte stands 

and the likelihood of organic-matter decomposition 

within the sediments. Because this core was collected 

from within a macrophyte stand (though after the macrophytes had died back), the macrophytes might have 

altered the nutrient profiles enough that the input history 

of the nutrients has been confounded. 

The steadily decreasing 210Pb activities below 

about 8 cm in the Musky Bay core indicate reasonably 

steady-state bulk sediment accumulation down to about 

45 cm (figs. 8–9). The upper 8 cm might thus represent 

the macrophyte root zone wherein sediments are 

affected by root-mediated reactions. Below this zone, 

the effects of macrophyte roots are assumed to be minimal. Further, given that macrophyte fragments are 

found throughout the upper 86 cm of the Musky Bay 

core, any reactions, including the sequestering of various elements by macrophytes, would have the same 

effect over the entire core. Thus, sediments below the 

root zone might still record elemental accumulation 

rates, albeit with potential chemical alteration prior to 

being buried below the root zone and with decreased 

temporal resolution. 

Examining nutrient concentrations in terms of 

ratios can help to determine the types of post-depositional chemical reactions that may be occurring, as well 

as the sources and input of the elements. Before elements can be examined in terms of ratios, concentrations (based on percent weight) are converted to 

mmol g-1, which then allows comparison on an atomby-atom basis. Typical ratios examined in this fashion 

were organic carbon:phosphorus (OC:P), nitrogen:phosphorus (N:P), and organic carbon:nitrogen 

(OC:N).

The OC:N:P ratio at the top of the core of 182:23:1 

(table 7) reflects a mixture of macrophyte and epiphytic 

algal sources and an additional source of nitrogen with 

respect to phosphorus. In the surficial sediment, the 

OC:N ratio (7.9) and OC:P ratio (182) are intermediate 

between those of macrophytes (OC:N = 17.4 and OC:P 

= 197; average of various species of Potamogeton, 

Myriophyllum, Ceratophyllum, Elodea, and Vallisneria; 

in Enríquez and others, 1993 and references within) and 

algae (OC:N = 6.6 and OC:P = 1.6; Redfield and others, 

1963). However, nitrogen is enriched with respect to 

phosphorus in the sediments compared to both of these 

organic detritus sources. The presence of inorganic 

fertilizer cannot explain this result; more than about 

95 percent of the total nitrogen in the core is estimated 

to be organically-bound based on commonly observed 

porewater and sorbed ammonium concentrations 
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 35

Table 7. Molar ratios of organic carbon (OC), nitrogen

(N), and phosphorus (P) in Musky Bay core MB-1A, 

1999

[cm, centimeter]

Midpoint depth

(cm) OC:N OC:N:P

1 7.9 182:23:1

2.5 8.4 209:25:1

4.5 8.4 284:34:1

6.5 9.2 348:38:1

9.5 9.0 385:43:1

12.5 9.5 475:50:1

15.5 9.7 476:49:1

18.5 10.0 590:59:1

21.5 10.0 580:58:1

24.5 10.0 632:63:1

27.5 10.6 677:64:1

30.5 10.2 712:70:1

33.5 10.8 711:66:1

36.5 10.8 817:76:1

40.5 10.7 835:78:1

45.6 10.6 929:88:1

51 10.9 935:86:1

61 11.4 1059:93:1

71 11.1 1024:92:1

85 11.2 1075:96:1

Figure 12. Mole-ratio profiles of (A) total organic carbon and total nitrogen (OC:N), (B) total nitrogen and total phosphorus 

(N:P), and total organic carbon and total phosphorus (OC:P) for Musky Bay core MB-1A.

RATIO, IN MOLE PER MOLE

A B C

0

10

20

30

40

50

60

70

80

90

0 500 1000 1500

OC:P

Replicate

ESTIMATED YEAR OF DEPOSITION

1892

1906

1916

1936

1868

1946

1958

1963

1970

1989

1980

1985

1996

0

10

20

30

40

50

60

70

80

90

0 50 100 150

N:P 

Replicate

1892

1906

1916

1936

1868

1946

1958

1963

1970

1989

1980

1985

1996

0

10

20

30

40

50

60

70

80

90

0 5 10 15

DEPTH, IN CENTIMETERS

OC:N

Replicate

1892

1906

1916

1936

1868

1946

1958

1963

1970

1989

1980

1985

1996
36 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

(Fitzgerald, unpublished data). The source of this nitrogen enrichment with respect to phosphorus is not known 

and further work is necessary to characterize its chemical form and likely source.

Sediment OC:N, OC:P, and N:P ratios increase 

with increasing depth in the Musky Bay core, indicating 

preferential recycling and loss of phosphorus with 

respect to both organic carbon and N and preferential 

recycling of N with respect to organic carbon (fig. 12). 

The OC:N in the upper two centimeters of the Musky 

Bay core was 7.9, within the range reported for 46 Minnesota Lakes (7.4–14; Dean and others, 1993) and the 

Laurentian Great Lakes (7–9; Kemp and others, 1977). 

These OC:N ratios reflect both the source (discussed 

above) and the relative freshness of the organic matter, 

in that the OC:N ratio at the top of the core (7.9) is close 

to that for live phytoplankton biomass (~6.6; Redfield 

and others, 1963). The OC:N ratio increases with depth 

until a fairly constant value of about 11 is reached below 

at depth of about 28 cm, reflecting more decomposed 

organic matter which has a OC:N ratio of about 10–20 

(Hakanson and Jansson, 2002). N:P and OC:P also start 

from minimum values and increase towards a relatively 

constant value. These plots are strong evidence that 

organic matter decomposition is responsible for at least 

some of the decrease of organic carbon, nitrogen and 

phosphorus concentrations with depth in the Musky 

Bay core. It would be extremely unlikely that organic 

carbon, nitrogen, and phosphorus input rates would 

vary in such a smoothly concerted fashion, in the 

absence of organic-matter decomposition or other biogeochemical processes that selectively retain or release 

these elements over several decades of deposition.

Another indication that the high nitrogen and phosphorus concentrations in the upper part of the core are 

due at least in part to diagenesis as opposed to increased 

input can be discerned from normalizing nitrogen and 

phosphorus concentrations to those for aluminum (Al) 

and organic content (LOI) (fig. 13). Aluminum concentration is used here as a proxy for the mineral fraction of 

the sediments, and organic content is a measure of the 

total organic matter in the sediments. The relative concentrations of both nitrogen and phosphorus decrease 

downcore with respect to both of these proxies over the 

upper third of the core, the location of fastest organic 

matter decomposition and nutrient recycling. Because 

these nutrients must have originally been deposited in 

association with one or both of these fractions, the 

changing relation with depth is very strong evidence 

that recycling of nitrogen and phosphorus from the sediments has caused most of the decrease in nitrogen and 

phosphorus concentration with depth. 

Postdepositional recycling, plus organic-matter 

decomposition, has been shown to alter the accumulation and burial rates of nonconservative sedimentary 

components such as organic carbon, nitrogen and phosphorus, and certain trace elements. (See Berner, 1980, 

for a general overview.) Phosphorus profiles in particular have been empirically shown to be inadequate for 

inferring historical ecosystem responses, including 

increased phosphorus input (Schelske and others, 1988; 

Anderson and Rippey, 1994). Phosphorus accumulation 

rates often underestimate inputs, as was shown for the 

Laurentian Great Lakes (Schelske, 1999), likely 

because of the preferential recycling of phosphorus with 

respect to other nutrients, among other things. There is 

clearly a lack of understanding of the factors that control phosphorus accumulation, and ultimately, burial, in 

sediments. In summary, the fact that nutrient profiles 

cannot be used to reconstruct input histories for Musky 

Bay is not to say that nutrients have not increased over 

the last few decades but only that diagensis and changes 

in input rates cannot be distinguished from each other. 

Minor and Trace Elements

Results for analysis of all minor and trace elements 

are shown in appendix table A4. Concentrations of 

selected trace elements in the Musky Bay MB-1 core 

also were normalized with aluminum concentrations. 

The normalized profiles were similar to the concentration profiles because aluminum concentrations were 

relatively constant throughout the profile (figs. 14–15). 

For the Musky Bay core, many trace elements typically associated with mineral matter, such as aluminum, iron, magnesium, manganese, potassium and 

sodium, showed relatively constant concentrations 

throughout the 85-cm profile (for example, aluminum in 

fig. 14A). Concentrations of these elements were also 

higher in the NE Bay core than in the Musky Bay core, 

indicating that the NE Bay core had a higher mineral 

content and lower organic content and organic carbon 

concentrations than Musky Bay MB-1 core (as previously shown in figs. 7 and 11). Profiles of calcium, 

chromium, and nickel in the Musky Bay core reflect the 

profiles related to mineral matter, except that concentrations slightly increase at the very top of the core 

(figs. 14B and 15). Evidence for calcium enrichment 

was found in a paleolimnological study on selected 

lakes near the Lac du Flambeau Indian Reservation and 
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 37

Figure 13. Profiles of nitrogen (N) and phosphorus (P) normalized to aluminium (AI) and organic content (LOI) in Musky 

Bay core MB-1A; (A) N:AI, (B) P:AI, (C) N:LOI, (D) P:LOI.

A B

C D

0.0 0.5 1.0 1.5 2.0 2.5

RATIO, 

IN MICROMOLES PER WEIGHT PERCENT

0 10 20 30 40 50 60

RATIO, 

IN MICROMOLES PER WEIGHT PERCENT

0 5 10 15 20 25 30 35 40 45

RATIO, IN MOLES PER MOLE x100

0 1 2 3 4 5 6 7 8 9 10

RATIO, IN MOLES PER MOLE

DEPTH, IN CENTIMETERS 0

10

20

30

40

50

60

70

80

90

P:LOI

DEPTH, IN CENTIMETERS

0

10

20

30

40

50

60

70

80

90

N:LOI

DEPTH, IN CENTIMETERS 0

10

20

30

40

50

60

70

80

90

P:Al

DEPTH, IN CENTIMETERS

0

10

20

30

40

50

60

70

80

90

N:Al

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996
38 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 14. Profiles of selected minor and trace elements in Musky Bay core MB-1A and Northeastern (NE) Bay core LCO-1A

for (A) aluminum, (B) calcium, (C) copper, and (D) lead. Dates refer to Musky Bay profiles only.

A B

C D

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

1868

1892

1906

1916

1936

1946

1958

1963

1970

1980

1985

1989

1996

0 20 40 60 80

DEPTH, IN CENTIMETERS

LEAD CONCENTRATION IN SEDIMENT, 

IN MICROGRAMS PER GRAM

Musky Bay

NE Bay

Musky Bay, replicate

NE Bay, replicate

ESTIMATED YEAR OF DEPOSITION

0

10

20

30

40

50

60

70

80

90 0 10 20 30 40 50 60

COPPER CONCENTRATION IN SEDIMENT, IN 

MICROGRAMS PER GRAM

DEPTH, IN CENTIMETERS 0

10

20

30

40

50

60

70

80

90

0 0.2 0.4 0.6 0.8 1

CALCIUM CONCENTRATION IN SEDIMENT,

IN PERCENT

DEPTH, IN CENTIMETERS 0

10

20

30

40

50

60

70

80

90

0 0.5 1 1.5 2 2.5

ALUMINUM CONCENTRATION IN SEDIMENT,

IN PERCENT

DEPTH, IN CENTIMETERS

0

10

20

30

40

50

60

70

80

90

EXPLANATION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 39

Figure 15. Profiles of selected minor and trace elements normalized to aluminum in Musky Bay core MB-1A.

0

10

20

30

40

50

60

70

80

90

012345678

 ELEMENTS NORMALIZED TO ALUMINUM IN SEDIMENT,

IN MICROGRAMS PER GRAM

DEPTH, IN CENTIMETERS

ESTIMATED YEAR OF DEPOSITION

1868

1892

1906

1916

1936

1958

1946

1963

1970

1989

1980

1985

1996

EXPLANATION

Cu:Al ratio * 1000

Pb:Al ratio * 1000

Ca:Al ratio

As:Al ratio * 1000

Cr:Al ratio * 1000

Ni:Al ratio * 1000

Zn:Al ratio * 100
40 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

was related to cranberry farming (Winkler and Sanford, 

2000). In this study, there does not appear to be any calcium enrichment in Musky Bay core, except possibly in 

the upper 5 cm. Calcium is sometimes used as a soil 

amendment in cranberry operations, although calcium 

concentrations were not especially high in cranberry 

bog soils, and calcium concentrations were higher in 

surficial sediment from Devils Lake than from Musky 

Bay (table A4). Differences in the results between this 

study and Winkler and Sanford (2000) are possibly due 

to differences in farming practices. In addition, as discussed earlier, input histories of iron, manganese, and 

possibly calcium could not be separated from postdepositional chemical reactions with the sediments.

In general, copper concentrations were similar in 

Musky Bay and NE Bay cores (fig. 14C). The aluminum-normalized copper profile in the Musky Bay core 

showed increases from background levels at about 50 

cm (1920s) probably corresponding with regional 

increases in smelting in the northern Great Lakes region 

(fig. 15). Concentrations slightly decrease above 20 cm 

(1980s) but then increase above 5 cm (mid-1990s) 

(fig. 14C). In addition to anthropogenic sources, copper 

is also an element in bacterial biomass (Gottschalk, 

1986) and macrophyte biomass. In addition to copper 

and calcium, aluminum-normalized concentrations of 

nickel and zinc also increased in the mid-1990s.

Lead concentrations in the Musky Bay core 

steadily increased after European settlement and peaked 

at about 25 cm (around 1970) just prior to the beginning 

of lead removal from gasoline in the mid-1970s 

(fig. 14D, fig. 15). As stated earlier, subsurface peaks in 

lead have been dated to this time period in other lakes 

(Gobeil and others, 1995; Callender and Van Metre, 

1997; Siver and Wozniak, 2001). The relatively low lead 

concentrations at the top of the core, which are lower 

than presettlement lead concentrations, suggest increasing proportions of organic matter, as shown in figure 7.

Concentrations of the cadmium from cores collected in 1999 from the Lac Courte Oreilles bays 

showed evidence of contamination from coring or subsampling equipment (table A4). Subsequent samples of 

surficial sediment from cores collected with a different 

core sampler in 2001 from the Lac Courte Oreilles bays 

and nearby soils and lakes indicate that cadmium concentrations in Musky Bay are not elevated and are similar to concentrations in Devils Lake sediment, a remote 

lake in the Lac Courte Oreilles reservation with no 

houses or cranberry bogs near it (table A4). A blank 

quality-control sample that was submitted in 2000 for 

the coring tube and subsampling equipment used in 

1999 contained relatively high cadmium (1.2 ppm) but 

the exact source for the cadmium contamination of 1999 

samples has not been identified. All other element concentrations were similar in 1999 and 2001 samples. 

Concentrations of arsenic, chromium, copper, lead, 

nickel, and zinc in the Musky Bay core and from all 

other surficial samples collected from the Lac Courte 

Oreilles bays and surrounding areas were all below consensus-based probable effect concentrations (PEC). A 

few samples were just above the threshold effects level 

(TEC) for arsenic from NE bay and Stucky Bay, for copper from Musky Bay, NE Bay, Stucky Bay, and Devils 

Lake; and for lead from NE Bay and Stucky Bay (table 

8; MacDonald and others, 2000; TEC, concentrations 

below which harmful effects on aquatic life are not 

likely to be oberved; PEC, concentrations above which 

harmful effects on aquatic life are likely to be 

observed). The source for these elements does not 

appear to be related to cranberry-bog practices or housing development because the concentrations above the 

TEC are found in areas without either type of landcover influence. This finding is contrary to the results 

from a study of other northern Wisconsin lakes near Lac 

du Flambeau tribal lands that associated historical 

increases in these elements with cranberry-bog practices (Winkler and Sanford, 2000), possibly because of 

differing cranberry farming techniques and soil amendments. As stated earlier, apparent increases in concentrations of these elements (except As) near the top of the 

Musky Bay core may also represent the last season’s 

macrophyte growth in an early stage of decomposition, 

in addition to a large population of sediment bacteria 

just below the sediment/water interface.

Biogenic Silica, Diatom Counts, and 

Biovolumes

In the Musky Bay core, biogenic silica concentrations generally increase from 16 percent near the bottom of the core (85 cm) to 32 percent at the sediment/ 

water interface (fig. 16). Biogenic silica concentrations 

in the core from NE Bay had a broad subsurface peak 

within the upper half (~16 cm) of the core (fig. 16). The 

biogenic silica profile for the Musky Bay core indicates 

that diatom production has steadily increased in Musky 

Bay since the 1930s. Assuming that the diatoms remain 

phosphorus limited over this entire period, the increase 

in diatom production is good evidence that phosphorus 
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 41

Table 8. Concentrations of organic content, arsenic, chromium, copper, lead, nickel, and zinc in selected surficial sediment from Lasurrounding areas, 1999 and 2001[cm, centimeter; ppm, parts per million; TEC, sediment-quality guideline below which harmful effects on selected aquatic organisms are unlikely to be observed (PEC, sediment-quality guideline above which harmful effects on selected aquatic organisms are likely to be observed (MacDonald and others, 2000)]

Location Core sample Depth (cm) Organic content (percent) As (ppm) Cr (ppm) Cu (ppm) Pb (ppm) 

(

Musky Bay MB-1-1 0–2 50 3.0 17 51 18 

Musky Bay MB-3-1 0–2 66 3.2 18 18 36 

Musky Bay MB-4-1 0–2 47 4.6 2.8 21 39 

Musky Bay MB-5-1 0–2 40 9.1 9.8 34 28 

Northeastern Bay LCO-1-1 0–1 41 12 36 35 58 

Northeastern Bay LCO-3-1 0–2 41 12 18 26 50 

Stucky Bay SB-1-1 0–1 39 9.9 32 40 45 

Stucky Bay SB-2-1 0–2 34 5.9 6.1 40 21 

Sand Lake SAN-1-1 0–2 0.61 2.0 1.5 3.2 5.0 <

Devils Lake DEV-1-1 0–2 31 3.0 30 33 21 

Ashegon Lake ASH-1-1 0–2 14 1.4 9.6 9.7 11 

Wetland soil WET-1-1 0–2 83 1.9 <1 10 19 

Cranberry farm JON-1-1 0–10 17 2.1 19 83 8.9 

Cranberry farm JON-1-2 0–10 11 2.6 26 67 8.2 

Cranberry farm ZAW-1-1 0–8 4.2 1.6 14 17 5.1 

TEC 9.8 43.4 31.6 35.8 PEC 33 111 149 128 
42 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 16. Comparison of profiles of biogenic silica concentrations in 

Musky and Northeastern bays. Dates refer to Musky Bay profiles only.

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30 35

BIOGENIC SILICA CONCENTRATION, 

IN WEIGHT PERCENT

DEPTH, IN CENTIMETERS

1868

1906

1916

1936

1958

1946

1970

1989

1980

1985

1996

1963

1892

ESTIMATED YEAR OF DEPOSITION

Musky Bay (MB-1B)

Northeastern Bay (LCO-1B)

Figure 17. Comparison of profiles of biogenic silica, diatom concentration, and biovolume in Musky Bay

core MB-1. 

0

10

20

30

40

50

60

70

80

90

100

0.0 20.0 40.0 60.0 80.0 100.0 120.0

CONCENTRATION

DEPTH, IN CENTIMETERS

1868

1892

1906

1916

1936

1958

1946

1970

1989

1980

1985

1996

1963

ESTIMATED YEAR OF DEPOSITION

Diatom counts, in valves

(x108) per gram, dry weight

(MB-1B)

Biogenic silica, in weight

percent (MB-1A)

Diatom total biovolume, in

cubic micrometers (x1011)

per gram, dry sediment

(MB-1B)

EXPLANATION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 43

inputs have increased in Musky Bay. As stated earlier, 

similar increases in biogenic silica accumulation have 

been shown to reflect increased phosphorus inputs in 

the Laurentian Great Lakes (Schelske and others, 1986; 

1988).

Profiles of diatom counts and biovolumes from the 

Musky Bay core were more variable than biogenic silica 

concentrations but do provide some additional evidence 

for recent increases in nutrient concentrations (fig. 17). 

Biovolumes are a better estimate of diatom silica 

changes than diatom counts are, especially in the Musky 

Bay core, because the dominant diatoms at the bottom 

of the core differ in size from those present in the upper 

part of the core. Although the increase in biogenic silica 

in the top 20 cm of the core is not as evident in the diatom biovolume profile, generally higher levels are indicated. The diatom biovolume and biogenic silica 

profiles in Musky Bay compare fairly closely considering the different results reported in the literature. For 

example, Digerfeldt (1972), Renberg (1976), and Engstrom and Wright (1984) reported little agreement 

between diatom counts and biogenic silica, whereas 

others have reported close agreement (Flower, 1980; 

Conley and others, 1989; and Wessels and others, 

1999).

Diatom Assemblages

Diatom diagrams for the two cores in Musky Bay 

(MB-1 and MB-3) and one core in NE Bay are shown in 

figures 18–20, respectively. As with the radiometric 

comparisons of the duplicate cores MB-1A and MB-1B, 

the comparison of selected diatom taxa in both cores 

from MB-1 was fairly close (fig. 21). Percentages of 

some taxa such as Fragilaria capucina Desmazières 

and Staurosira construens (Ehren.) Williams and 

Round (1987) agreed very closely, whereas small Navicula and Achnanthidium minutissima Kützing agreed 

closely at the top but not as closely at the bottom, possibly because recovery ratios differed between the two 

cores. Overall, the agreement seems close enough to 

conclude that these cores are comparable. 

Musky Bay

At both of the Musky Bay sites, diatoms associated 

with benthic substrates (bottom sediments or aquatic 

plants), for example, Staurosirella spp. and Staurosira 

spp. comprised the large majority of the community 

throughout the cores (figs. 18 and 19). Open-water diatoms (planktonic) were somewhat more common at site 

MB-3, reflecting its distance further away from shore 

(figs. 1, 22). The most common open-water diatoms 

were Aulacoseira ambigua (Grun.) Simonsen and 

Cyclotella comensis Grunow. These were the dominant 

taxa found in the core collected from the deep basin of 

the lake (appendix B).

The lower parts of the Musky Bay MB-1 and 

MB-3 cores were dominated by small benthic species of 

Achnanthidium (A. minutissima), Navicula (N. 

pseudoventralis, Hustedt; N. atomus var. permitis, 

(Hust.) Lange-Bertalot; N. minima, Grunow), and 

Fragilaria (figs. 18, 19, and 22). (Diatoms referred to as 

benthic Fragilaria are displayed in the figures as Staurosira, Staurosirella, and Pseudostaurosira as separated 

by Williams and Round (1987).) These taxa have been 

shown to dominate the nonplanktonic (non-floating) 

diatom component of shallow water bodies in several 

studies (Osborne and Moss, 1977; Battarbee, 1986; 

Anderson, 1989). Because of a variety of factors (such 

as steep gradients of space and light availability, water 

turbulence, and grazing) benthic diatoms may not 

always respond in a predictable or direct manner to 

eutrophication (Hall and Smol, 1999) although Anderson (1990) showed that these types of diatoms supplied 

information concerning changes in littoral zone conditions during the eutrophication of an Irish lake. Often, 

these diatoms respond more to changes in substratum 

and algal-mat chemistry than directly to changes in 

water chemistry (Hansson, 1988, 1992; Cattaneo, 

1987); however, in a whole-lake-basin perspective, 

benthic communities may actually respond more rapidly to eutrophication than planktonic algae (Goldman, 

1981; Kann and Falter, 1989; Hawes and Smith, 1992). 

It is likely that benthic diatoms in Musky Bay are 

responding to changes in the physical environment of 

the bay. Potential changes that have occurred in the bay 

from cultural eutrophication include an increase in 

nutrients along with an increase in the density of macrophyte growth. All of the common benthic Fragilaria

produce long filamentous chains (Patrick and Reimer, 

1966; Round and others, 1990). These diatoms have 

been known to inhabit the surface of the sediments 

(Round, 1981; Hickman and White, 1989; Round and 

others, 1990; Bennion, 1995). Although these diatoms 

may be present under low nutrient conditions with little 

macrophyte cover (Garrison and Wakeman, 2000) it 

seems more likely that their high levels in Musky Bay 

are the result of increased macrophyte growth. Jor-
44 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 18. Profiles of selected diatoms in Musky Bay core MB-1B, October 1999.

PERCENTAGE OF TOTAL DIATOMS

0 20

40

50

60

70

80

90

100

DEPTH, IN CENTIMETERS

0 0 20 0 0 0 20 0 0 20 0 20 0 0 20 0

0

10

20

30 1963

1946

1989

1980

1916

1906

1892

1868

1936

1958

1970

1996

1985

Achnanthidium minutissima

Navicula pseudoventralis

N. atomus var. permitis

N. minima

N. pelliculosa

Pseudostaurosira brevistrata

Staurosira elliptica

Staurosirella pinnata

Staurosira construens var. venter

S. construens var. binodis

S. construens

Fragilaria capucina

BENTHIC FRAGILARIA

ESTIMATED YEAR OF DEPOSITION

Indicative of low phosphorus concentrations

Unaffected by phosphorus concentrations

Indicative of high phosphorus concentrations

Indicative of the floating algal mat

EXPLANATION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 45

Figure 19. Profiles of selected diatoms in Musky Bay core MB-3, October 1999. The dates in brackets are estimated

from core MB-1.

0 20

0

10

20

30

40

50

60

70

80

DEPTH, IN CENTIMETERS

0 0 0 0 20 0 20

PERCENTAGE OF TOTAL DIATOMS

0 0 20 0 20

[1916]

[1996]

[1946]

[1980]

[1963]

[1989]

[1906]

[1892]

[1936]

[1985]

[1958]

[1970]

Achnanthidium minutissima

Navicula pseudoventralis

N. minima

Aulacoseira ambigua

Pseudostaurosira brevistrata

Staurosirella pinnata

Staurosira construens var. venter

S. construens

Fragilaria capucina

BENTHIC FRAGILARIA

ESTIMATED YEAR OF DEPOSITION

Indicative of low phosphorus concentrations

Unaffected by phosphorus concentrations

Indicative of high phosphorus concentrations

Indicative of the floating algal mat

EXPLANATION
46 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 20. Profiles of selected diatoms in Northeastern Bay core LCO-1B, October 1999.

0.5

10.5

16.5

24.5

40.5

DEPTH, IN CENTIMETERS

0 10 0 10 0 10 0 10 0 10 20 0 10 20 0 10 0 10 0 10 20 30 40 50 60

PERCENTAGE OF TOTAL DIATOMS

Aulacoseira ambigua

Cyclotella comensis

Pseudostaurosira brevistrata

S. construens

Staurosira elliptica

S. construens var. venterStaurosirella pinnata

Small NaviculaBenthic Fragilaria

BENTHIC FRAGILARIA

Planktonic

 Unaffected by phosphorus concentrations

Indicative of high phosphorus concentrations

Indicative of low phosphorus concentrations

EXPLANATION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 47

Figure 21. Comparison of diatom assemblages in side-by-side cores collected from Musky Bay 

core MB-1, October 1999. The error bars illustrate one standard deviation.

Fragilaria capucina + vars. 

DEPTH, IN CENTIMETERS

0 5 10 15 20

0

10

20

30

40

50

60

70

Pseudostaurosira brevistrata + vars.

0 5 10 15 20

0

10

20

30

40

50

60

70

Benthic Fragilaria

30 40 50 60 70 80 90

0

10

20

30

40

50

60

70

Small Navicula

0 10 20 30 40

0

10

20

30

40

50

60

70

Achnanthidium minutissima + vars.

0 5 10 15 20

0

10

20

30

40

50

60

70

PERCENTAGE OF TOTAL DIATOMS

Staurosira construens

0 10 20 30 40

0

10

20

30

40

50

60

70

DEPTH, IN CENTIMETERS DEPTH, IN CENTIMETERS

Diatom data from core MB-1B

Diatom data from core MB-1A

EXPLANATION
48 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure 22. Profiles of planktonic diatoms, small Navicula, and benthic Fragilaria for two cores in Musky Bay (MB-1B and 

MB-3) and one core in Northeastern Bay (LCO-1B), October 1999. The dates in brackets for core MB-3 are estimated from 

core MB-1B.

Planktonic Diatoms

0 10 20 30

0

20

40

60

80

100

DEPTH, IN CENTIMETERS

Small Navicula

0 10 20 30 40 50

Benthic Fragilaria 

0 20 40 60 80

MB-1

1996

1980

1963

1946

1916

1892

1906

1868

1989 1985

1970

1958

1936

20 30

0

20

40

60

80

DEPTH, IN CENTIMETERS

0 10 0 5 10 15 20 0 20 40 60

MB-3

[1996]

[1980]

[1963]

[1946]

[1916]

[1892]

[1906]

[1989]

[1970]

[1958]

[1936]

[1985]

0

10

20

30

40

50

DEPTH, IN CENTIMETERS

0 10 20

PERCENTAGE OF TOTAL DIATOMS

0 10 20 30 0 20 40 60 80

LCO-1

ESTIMATED YEAR OF DEPOSITION
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 49

gensen (1948) and Florin (1970) found that these 

benthic Fragilaria were common in littoral zones of 

eutrophic lakes. These chain-forming diatoms are susceptible to wind mixing and being redistributed into 

deeper waters. Macrophytes themselves can influence 

the hydrodynamics of a lake basin through sediment 

trapping by roots and stems (Carpenter and Lodge, 

1986). As macrophytes become more abundant as a 

consequence of increased nutrients, productivity of 

these diatoms increases, and the increased plants restrict 

water movement, thus the diatoms are less likely to be 

displaced into deeper waters. Cores from a number of 

other northern Wisconsin lakes have similarly shown an 

increase in these benthic Fragilaria after European settlement as macrophyte density has increased (Garrison 

and Winkelman, 1996; P.J. Garrison, Wisconsin Department of Natural Resources, unpublished data, 2002). 

Bradbury and Winter (1976) also found benthic Fragilaria in association with macrophytes in eutrophic Lake 

Sallie, Minnesota. Further evidence of the presence of 

macrophytes at the bottom of the core is the presence of 

Achnanthidium minutissima (figs. 17, 18, and 20). This 

diatom, which has been found to be associated with 

macrophytes (Moss, 1978; Reavie and Smol, 1997; 

Garrison and Wakeman, 2000), was most common near 

the bottom of the core and declined upcore around 40 

cm (1940s) in cores MB-1 and MB-3. 

Less is known about the small Navicula species 

found in the cores in this study (figs. 17–19). Although 

these diatoms were not present in large numbers in other 

studies, their optimal total phosphorus concentrations 

were some of the lowest for the benthic species (Fritz 

and others, 1993; Bennion, 1994; Dixit and others, 

1999). In addition, N. pseudoventralis, N. atomus var. 

permitis, and N. minima were found in a calibration set 

constructed for Wisconsin lakes to have low total phosphorus optima (P.J. Garrison, Wisconsin Department of 

Natural Resources, unpublished data, 2002). It seems 

likely in Musky Bay that A. minutissima and small Navicula taxa are indicative of low phosphorus concentrations, whereas the benthic Fragilaria are indicative of 

denser macrophyte growth and possibly higher phosphorus concentrations in water. Carpenter (1981) and 

Wetzel (1983) reported that with increased phosphorus 

inputs there is an increase in macrophyte productivity 

until algal growth shades the plants.

As Achnanthidium and Navicula declined in MB-1, 

small Fragilaria increased (examples include Staurosira construens, S. construens var. venter (Ehren.), S. 

construens var. binodis (Ehren.), and Staurosirella pinnata (Ehren.) Williams and Round (1987), fig. 18). The 

increase in S. construens var. binodis is especially informative. This diatom was found growing attached to 

macrophytes in areas of Lake Sallie (Minnesota) with 

the highest phosphorus levels (Bradbury and Winter, 

1976). The increase of these taxa during the 1940s is 

further indication of the increase in nutrients beginning 

at this time. Their increase also likely indicates an 

increase in macrophyte growth in Musky Bay. 

The diatom community at site MB-3 indicates a 

greater change throughout the core than at MB-1 

(figs. 18, 19, and 22). This is probably because site 

MB-1 is close to shore and macrophytes have been 

present in significant numbers for at least the last 

100 years at this site. The diatom community indicates 

that greater changes have occurred farther out in Musky 

Bay. There was a greater decline in A. minutissima

around 40 cm (1940s) and a larger increase in S. construens first at 40 cm and again at 25 cm (around 1970). 

The increase in the latter diatom likely reflects an 

increase in nutrients, resulting in more extensive macrophyte growth. Around 25 cm (1970), there also was a 

decline in the planktonic diatom A. ambigua that likely 

reflects a further increase in macrophyte growth. Planktonic diatoms probably were not present in fewer numbers; instead, the number of benthic diatoms increased 

diluting the representation of planktonic species. 

There was a 1- to almost 20-percent increase in the 

diatom Fragilaria capucina in the top 5–10 cm of the 

MB-1 and MB-3 cores (figs. 17–18). This diatom commonly increases under elevated nutrient levels (Stoermer and Yang, 1970; Bradbury, 1975; Stoermer and 

others, 1985; Reavie and others, 1995; Stoermer and 

others, 1996). Surface sediment studies in Wisconsin 

and other U.S. lakes have found that this diatom has a 

high phosphorus optimum compared to other diatoms 

(P.J. Garrison, Wisconsin Department of Natural 

Resources, unpublished data, 2002; Bennion, 1994; 

Fritz and others, 1993; Dixit and others, 1999). 

F. capucina was also found to be the dominant diatom 

associated with the floating algal mat in Musky Bay in 

August 1999. Although the algal mat was made up 

largely of filamentous blue-green algae, a number of 

diatoms grew attached to the mat. The diatom present in 

the highest numbers was F. capucina. The size of the 

floating algal mat appears to have increased greatly in 

the last decade at both sites. This size increase likely 
50 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

indicates a significant increase in phosphorus levels in 

Musky Bay.

Northeastern Bay

Because of the dating problems associated with the 

NE Bay core, fewer diatom samples were examined 

than in the Musky Bay cores. On the basis of the 210Pb 

profile (fig. 8B), samples below 15 cm likely represent 

sediment that was deposited much earlier, whereas the 

upper part of the core reflects sediment that was deposited more recently. As with Musky Bay, benthic diatoms 

dominate the community (fig. 20). In fact, the common 

taxa in the Musky Bay cores (figs. 18–19) are also found 

in NE Bay core. In general, the community was more 

diverse in the NE Bay than Musky Bay. Although 

benthic Fragilaria were the dominant diatoms in the NE 

Bay core, the trend differs from that in the Musky Bay 

cores. The peak of this macrophyte-inhabiting diatom is 

at 16.5 cm in the NE Bay core whereas it is in the upper 

part of the cores in Musky Bay (fig. 22). This peak in 

apparent macrophyte growth occurs just below the 

major discontinuity in the core, recorded in bulk density 

and radiometric profiles. It is perhaps an indicator of 

slightly shallower water prior to the increase in head at 

the Billy Boy dam in about 1936. These benthic Fragilaria generally decline in the upper part of the core in 

NE Bay. In contrast to Musky Bay core MB-3, the 

planktonic diatoms such as C. comensis reach their 

highest levels at the top of the core. Apparently, some 

macrophytes have been present in the NE Bay during 

the last 100 or more years, but their growth has not significantly increased as in Musky Bay.

In summary, the diatom community was dominated 

by benthic diatoms including A. minutissima, small 

Navicula, and Fragilaria at the bottom of cores from 

Musky Bay (figs. 18, 19, and 22). The first two diatoms 

are indicative of low nutrient levels in Musky Bay. The 

low-nutrient-indicating diatoms declined upcore 

between 40–25 cm and high-nutrient-indicating diatoms such as benthic Fragilaria, increased substantially. 

The time period of this increase in nutrients was 1940 to 

1970. In contrast, in the NE Bay, the benthic diatoms 

declined in the upper part of the core and were replaced 

by planktonic diatoms. It appears that Musky Bay has 

experienced much greater increases in nutrients and 

macrophyte growth compared with the NE Bay. There 

appears to be a significant increase in nutrients in 

Musky Bay beginning around the mid-1990s as indicated by the increase in F. capucina. The increase of this 

diatom also indicates a significant expansion of the 

floating algal mat (fig. 2). The primary difference in 

land use in the watershed of the Musky and NE bays is 

the presence of two cranberry bogs on Musky Bay. Winkler and Sanford (2000) found evidence in the diatomassemblage record for increased nutrient loading starting in the 1940s near the Lac du Flambeau Tribal lands, 

coincident with expansion of cranberry farming. Even 

though their cores were not collected in the littoral zone 

of the lakes, they documented similar changes in the 

diatom community as was seen in Musky Bay. Specifically, they saw an increase in benthic Fragilaria in 

response to the addition of phosphorus attributed to the 

cranberry operations.

Pollen

Pollen profiles from the Musky Bay MB-3 core 

indicate changes in some plant species over the last 

100+ years (fig. 23). The majority of the pollen in 

MB-3 was terrestrial and it was mostly arboreal (trees 

and shrubs). Of this group, pollen from pine trees generally composed over 40 percent of the pollen count 

(fig. 23). This reflects the high number of pine trees near 

the shoreline as well as their high production of pollen. 

Even though there was considerable logging activity in 

the area during the late 1800’s, this does not appear to 

have had an impact upon the pine pollen production at 

this site. Birch and oak were also an important component of the pollen record. 

Of the herbs, only ragweed and non-aquatic grass 

pollen were present in significant numbers. The 

increase in ragweed near the bottom of the core likely is 

the result of land disturbance as a result of the logging 

activity and human settlement. During the last 25 years, 

grass pollen increased (fig. 23). This likely is the result 

of continued shoreline development on Musky Bay. As 

lawns replace native vegetation more grass pollen enters 

the bay. 

The most important pollen profiles from MB-3 for 

this study are the aquatic pollen; wild rice (Zizania 

palustris) in particular (fig. 23). Wild rice pollen was 

present from the bottom of the core until about 1920, 

when it rapidly disappeared. The disappearance of wild 

rice occurs just before the rapid increase in benthic 

Fragilaria (fig. 22), and may have corresponded to a 

potential change (most likely increase) in water level 

associated with the reconstruction of the Billy Boy dam, 

an increase in mineral sediment input, and (or) an 
HISTORICAL TRENDS FROM MUSKY BAY AND NORTHEASTERN BAY 51

Figure 23. Pollen diagram from Musky Bay core MB-3, October 1999. The dates in brackets are estimated from core MB-1B. 

Aquatic pollen percentages were calculated by dividing aquatic pollen by total terrestrial pollen count.

0

10

20

30

40

50

60

70

80

90

PERCENTAGE OF TERRESTRIAL POLLEN

DEPTH, IN CENTIMETERS

Pine

Fir

Birch

Oak

Ironwood

Alder

Ragweed

Grass

Wild rice

Cattail-Burweed

Pondweeds

Bladderwort

Milfoil

Trees and Shrubs Herbs Aquatics

[1892]

[1916]

[1989]

[1946]

[1980]

[1963]

[1868]

[1906]

[1996]

[1985]

[1970]

[1958]

[1936]

0 20 40 60 0 0 20 0 20 0 0 0 0 0 20 0 20 0 20 0 200 20

ESTIMATED YEAR OF DEPOSTION

5X Exaggeration

EXPLANATION
52 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

increase in turbidity. Other aquatic pollen such as cattail-burweed, pondweeds and bladderwort were present 

throughout the core. This indicates that aquatic plants 

have been present in the bay for at least the last 

100+ years. The diatom community data also supports 

this finding. Milfoil pollen was only found in very low 

concentrations at the bottom of the core but its numbers 

increased after the disappearance of rice pollen after 

about 1920. Other paleolimnological studies have found 

that the macrophyte community increases in response to 

increased phosphorus levels (Garrison and Winkelman, 

1996; Garrison and Wakeman, 2000).

SUMMARY AND CONCLUSIONS

The U.S. Geological Survey and Wisconsin 

Department of Natural Resources collected several sediment cores from Musky Bay, Lac Courte Oreilles, and 

from surrounding areas in 1999 and 2001 to determine 

whether the water quality of Musky Bay has declined 

during the last 100 years or more as a result of human 

activity, specifically cottage development and cranberry 

farming. This study was done in cooperation with the 

Lac Courte Oreilles Tribe and the Wisconsin Department of Agriculture, Trade, and Consumer Protection. 

Selected cores were analyzed for sedimentation rates, 

minor and trace elements, nutrients, biogenic silica, diatom assemblages, and pollen over the past several 

decades. Much of the analysis was done on two cores 

from Musky Bay (one near cottage development on the 

northeast side of the bay and the other near a discharge 

outlet for a cranberry bog on the southeast side of the 

bay) and one core from the Northeastern Bay. 

Comparison of historical maps and aerial photographs indicates that shoreline development commenced about 1930 and that two cranberry bogs were 

constructed along Musky Bay in about 1939 and the 

early 1950s. Cranberry bogs on Musky Bay were substantially expanded during the periods 1950–62 and 

1980–98. Shoreline development on Musky Bay has 

increased steadily since about 1930. Currently housing 

density on Musky Bay is one-third to one-half the housing density surrounding three other Lac Courte Oreilles 

bays. 

Sedimentation rates were reconstructed for a core 

from Musky Bay by use of three lead radioisotope 

(

210Pb) models (constant initial concentration, constant 

rate of supply, and an adjusted constant rate of supply), 

and the profile of the radioisotope cesium-137 (137Cs) 

in the sediment. Of these methods, dates estimated from 

the 137Cs profile proved to be the least problematic. On 

the basis of the 137Cs profile, the estimated historical 

average mass and linear sedimentation rates for Musky 

Bay are 0.023 grams per square centimeter per year and 

0.84 centimeters per year, respectively. The profile for 

total lead-210 (210Pb) activity (normally smooth for 

constant sedimentation rates and 210Pb inputs) had two 

breaks, one at about 8 cm and the other at about 45 cm). 

Based on 137Cs -derived dates, these two breaks 

occurred at about the early 1990s and mid-1930s. The 

two constant rate of supply models indicated an 

increase in sedimentation after the early 1990s. Radiometric data were also collected for a core from the 

Northeastern Bay in Lac Courte Oreilles (surrounded by 

houses but no cranberry bogs) but the profiles reflected 

postdepositional disturbance, and sedimentation rates 

could not be calculated and compared to the Musky Bay 

core.

For the two Musky Bay cores, profiles of bulk density and organic matter suggest disturbance at about 

45 cm. Bulk density decreases upcore above 45 cm 

(mid-1930s) in the core closest to cottage development, 

and in the core closest to the cranberry farm bulk density peaks at about 45 cm then continues to decrease 

upcore. The profiles for organic matter for the two cores 

diverge at this interval, with percentages of organic matter increasing upcore in the core closest to cottage 

development and decreasing upcore in the core closest 

to the cranberry-bog discharge. These changes are coincident in the timing with the rebuilding of the Billy Boy 

dam (about 1936 and located downstream of Lac Courte 

Oreilles) and the onset of cranberry farming (1939). The 

head on the Billy Boy dam was raised at this time but it 

is not known how much this increase affected water levels in Lac Courte Oreilles.

Input histories of organic carbon, nitrogen, phosphorus, and sulfur for Musky Bay are potentially confounded by organic-matter decomposition and chemical 

redistribution after deposition. Therefore, profiles of 

organic carbon, nitrogen, phosphorus, and sulfur were 

not directly useful for reconstructing nutrient input histories.

No identifiable influences from cranberry bogs or 

shoreline development were evident in the minor- and 

trace-element profiles for Musky Bay. These profiles 

from the Musky Bay core possibly reflect historical 

changes in the input of clastic material over time, as 

well as potential changes in atmospheric deposition 

inputs. The input of clastic material to the bay slightly 
REFERENCES CITED 53

increased after European settlement and possibly in the 

1930s through 1950s. Concentrations of copper in the 

Musky Bay core increased steadily through the early to 

mid-1900s until about 1980 and appear to reflect inputs 

from atmospheric deposition. Aluminum-normalized 

concentrations of calcium, copper, nickel, and zinc 

increased in the Musky Bay core in the mid-1990s. Concentrations of these elements in surficial sediment from 

Musky Bay were similar to concentrations in other Lac 

Courte Oreilles bays, nearby lakes, and soils. All concentrations were below probable effects concentrations 

for aquatic life.

Contrary to core samples collected in 1999, cadmium concentrations in core samples collected in 2001 

with a different corer were not elevated in Musky Bay 

or surrounding areas. The exact source for the cadmium 

contamination of 1999 samples has not been identified. 

All other element concentrations were similar in 1999 

and 2001 samples. 

Evidence from biogenic-silica, diatom-community, 

and pollen data indicate that Musky Bay has become 

more eutrophic since about 1940 with the onset of 

shoreline development and cranberry farming. The 

water quality of the bay has especially degraded during 

the last 25 years with increased growth of aquatic plants 

and the onset of a floating algal mat during the last 

decade. Several lines of evidence indicate that nutrient 

input to the bay has increased after about 1940 and 

again in the 1990s: (1) the diatom assemblage data indicate a shift from low-nutrient species to higher-nutrient 

species during the 1940s, (2) the diatom assemblage 

indicate that aquatic plants reached their present density 

and/or composition during the 1970s, (3) the diatom 

Fragilaria capucina (indicative of the algal mat) greatly 

increased during the mid-1990s, (4) pollen data indicate 

that milfoil, which often becomes more common with 

elevated nutrients, became more common after 1920, 

and (5) biogenic silica data indicate that diatom production has consistently increased since the 1930s. Pollen 

data also indicate that wild rice was present in the eastern end of Musky Bay prior to the early 1800s until 

about 1920; the loss of wild rice after about 1920 was 

probably related to water-level changes and not 

eutrophication.

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APPENDIXES A–B 59

APPENDIXES A–B
60 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A1. Results from analysis of water content, loss on ignition, bulk density, and porosity data from core samples 

collected from Lac Courte Oreilles, October 1999 and July 2001

[cm, centimeter; g, gram]

Field

no.

Date

collected

Top

interval 

(cm)

Bottom 

interval 

(cm)

Water weight 

(percent)

Organic

content

(percent)

Bulk density 

(g/cm3)

Porosity

(percent)

MB-1-1 10/12/99 0 1 98.4 50.0 0.016 99.3

MB-1-2 10/12/99 1 2 98.3 50.4 .017 99.3

MB-1-3 10/12/99 2 3 98.1 49.2 .019 99.2

MB-1-5 10/12/99 4 5 97.3 49.8 .027 98.9

MB-1-7 10/12/99 6 7 97.6 50.0 .024 99.0

MB-1-9 10/12/99 8 9 97.1 49.2 .029 98.8

MB-1-11 10/12/99 10 11 97.3 49.0 .027 98.9

MB-1-13 10/12/99 12 13 97.5 49.0 .025 99.0

MB-1-15 10/12/99 14 15 97.2 48.3 .028 98.8

MB-1-17 10/12/99 16 17 97.4 47.7 .026 98.9

MB-1-19 10/12/99 18 19 97.1 48.6 .029 98.8

MB-1-19R 10/12/99 18 19 97.3 47.5 .027 98.9

MB-1-21 10/12/99 20 21 97.3 48.1 .027 98.9

MB-1-23 10/12/99 22 23 97.1 49.5 .029 98.8

MB-1-25 10/12/99 24 25 96.9 50.0 .032 98.7

MB-1-27 10/12/99 26 27 97.0 48.0 .030 98.8

MB-1-29 10/12/99 28 29 96.6 47.3 .035 98.6

MB-1-31 10/12/99 30 31 96.7 47.2 .034 98.6

MB-1-33 10/12/99 32 33 96.4 45.9 .037 98.5

MB-1-35 10/12/99 34 35 96.4 45.9 .037 98.5

MB-1-37 10/12/99 36 37 96.4 45.6 .037 98.5

MB-1-39 10/12/99 38 39 96.3 46.4 .038 98.5

MB-1-39R 10/12/99 38 39 96.1 46.7 .040 98.4

MB-1-41 10/12/99 40 41 94.1 47.4 .061 97.5

MB-1-42 10/12/99 41 42 93.4 49.9 .068 97.2

MB-1-43 10/12/99 42 43 94.9 49.3 .052 97.9

MB-1-44 10/12/99 43 44 94.6 50.8 .056 97.7

MB-1-45 10/12/99 44 45 95.7 50.2 .044 98.2

MB-1-47 10/12/99 46 47 95.7 51.2 .044 98.2
Table A1 61

MB-1-49 10/12/99 48 49 95.7 51.1 .044 98.2

MB-1-51 10/12/99 50 52 96.0 51.7 .041 98.3

MB-1-53 10/12/99 54 56 96.1 52.5 .040 98.4

MB-1-55 10/12/99 58 60 96.1 55.9 .040 98.4

MB-1-57 10/12/99 62 64 95.8 55.0 .043 98.2

MB-1-59 10/12/99 66 68 96.1 56.4 .040 98.4

MB-1-59R 10/12/99 66 68 96.0 56.4 .041 98.3

MB-1-61 10/12/99 70 72 95.8 56.8 .043 98.2

MB-1-63 10/12/99 74 76 96.1 57.8 .040 98.4

MB-1-65 10/12/99 78 80 94.2 60.6 .060 97.5

MB-1-65R 10/12/99 78 80 94.1 60.2 .061 97.5

MB-1-67 10/12/99 82 84 96.6 62.8 .035 98.6

MB-1-69 10/12/99 86 88 96.2 63.8 .039 98.4

MB-1-71 10/12/99 90 92 96.3 63.3 .038 98.5

MB-1-73 10/12/99 94 96 96.2 63.9 .039 98.4

MB-3-1 10/12/99 0 2 98.0 65.6 .020 99.2

MB-4-1 07/24/01 0 2 98.4 46.8 .016 99.3

MB-5-1 07/25/01 0 2 97.9 40.0 .021 99.1

LCO-1-1 10/13/99 0 1 96.3 41.4 .038 98.5

LCO-1-3 10/13/99 2 3 94.8 37.9 .053 97.8

LCO-1-5 10/13/99 4 5 94.3 40.1 .059 97.6

LCO-1-7 10/13/99 6 7 93.5 35.5 .067 97.2

LCO-1-9 10/13/99 8 9 93.1 28.7 .072 97.1

LCO-1-11 10/13/99 10 11 94.1 36.3 .061 97.5

LCO-1-13 10/13/99 12 13 93.7 39.8 .065 97.3

LCO-1-15 10/13/99 14 15 92.6 34.2 .077 96.8

LCO-1-17 10/13/99 16 17 73.1 7.6 .320 86.9

LCO-1-19 10/13/99 18 19 78.2 11.2 .250 89.8

LCO-1-21 10/13/99 20 21 83.4 17.0 .183 92.5

LCO-1-23 10/13/99 22 23 91.2 32.4 .092 96.2

Table A1. Results from analysis of water content, loss on ignition, bulk density, and porosity data from core samples 

collected from Lac Courte Oreilles, October 1999 and July 2001—Continued

[cm, centimeter; g, gram]

Field

no.

Date

collected

Top

interval 

(cm)

Bottom 

interval 

(cm)

Water weight 

(percent)

Organic

content

(percent)

Bulk density 

(g/cm3)

Porosity

(percent)
62 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

LCO-1-25 10/13/99 24 25 92.3 45.1 .080 96.7

LCO-1-27 10/13/99 26 27 9.7 37.6 .098 96.0

LCO-1-29 10/13/99 28 29 9.9 39.6 .096 96.1

LCO-1-31 10/13/99 30 31 9.7 36.0 .098 96.0

LCO-1-33 10/13/99 32 33 91.9 40.3 .085 96.5

LCO-1-35 10/13/99 34 35 92.3 43.1 .080 96.7

LCO-1-37 10/13/99 36 37 91.6 41.9 .088 96.4

LCO-1-39 10/13/99 38 39 91.4 40.9 .090 96.3

LCO-1-39R 10/13/99 38 39 91.5 41.3 .089 96.3

LCO-1-41 10/13/99 40 41 9.9 41.6 .096 96.1

LCO-1-43 10/13/99 42 43 89.4 34.6 .112 95.4

LCO-1-45 10/13/99 44 45 88.8 31.8 .119 95.1

LCO-1-47 10/13/99 46 47 77.8 13.5 .255 89.6

LCO-1-49 10/13/99 48 49 92.6 49.2 .077 96.8

LCO-3-1 07/25/01 0 2 97.8 40.9 .022 99.1

SB-1-1 10/13/99 0 1 87.9 38.5 .129 94.7

SB-1-3 10/13/99 2 3 93.7 38.9 .065 97.3

SB-2-1 07/25/01 0 2 97.9 34.2 .021 99.1

SAN-1-1 07/25/01 0 2 23.5 .6 1.41 42.9

DEV-1-1 07/25/01 0 2 94.8 31.4 .054 97.8

ASH-1-1 07/25/01 0 2 75.5 13.6 .286 88.3

WET-1-1 08/14/01 0 2 9.2 82.7 .102 95.8

LEV-1-1 09/27/01 0 2 14.1 6.5 1.74 28.7

JON-1-1 07/24/01 0 10 51.7 16.5 .669 72.4

JON-1-1R 07/24/01 0 10 43.0 11.0 .854 64.9

ZAW-1-1 07/24/01 0 8 21.3 4.2 1.48 39.9

ZAW-1-1R 07/24/01 0 8 19.8 na na na

Table A1. Results from analysis of water content, loss on ignition, bulk density, and porosity data from core samples 

collected from Lac Courte Oreilles, October 1999 and July 2001—Continued

[cm, centimeter; g, gram]

Field

no.

Date

collected

Top

interval 

(cm)

Bottom 

interval 

(cm)

Water weight 

(percent)

Organic

content

(percent)

Bulk density 

(g/cm3)

Porosity

(percent)
Table A2 63

Table A2. Results from particle-size analysis of lake and soil samples collected in July 2001 from 

areas surrounding Lac Courte Oreilles

[cm, centimeter]

Field 

no.

Date

collected

Top interval 

(cm)

Bottom interval 

(cm)

Percent

sand

Percent 

silt/clay

LCO-3-1 07/25/01 0 2 63.9 36.1

SAN-1-1 07/25/01 0 2 99.3 0.7

ASH-1-1 07/25/01 0 2 79.0 21.0

JON-1-1 07/24/01 0 10 90.8 9.2

JON-1-1R 07/24/01 0 10 91.4 8.6

ZAW-1-1 07/24/01 0 8 97.5 2.5
64 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores Table A3. Results from analysis of 210Pb, 226Ra, and 137Cs from core samples from Musky Bay and Northeastern Bay, Lac Courte Oreille

[LLD, limit of detection; pCi g-1, picocuries per gram] Top interval (cm) Bottom interval (cm) Total 210Pb activity (pCi g-1) Total 210Pb Uncertainty (pCi g-1) Total 210Pb LLD (pCi g-1) 226Ra activity (pCi g-1) 226Ra Uncertainty (pCi g-1) 226Ra LLD (pCi g-1) 137Cs activity (pCi g-1) 

U

Musky Bay core (MB-1B) 0 2 10.65 2.02 2.72 0.21 0.20 0.61 3.00 

8 10 14.15 1.52 1.87 .15 .15 .45 4.26 

12 14 12.33 1.00 1.26 -.14 -.10 .31 5.95 14 16 13.20 1.11 1.36 .16 .11 .33 3.73 16 18 12.23 1.52 1.95 .01 .16 .51 7.12 20 23 9.45 1.49 1.93 .10 .14 .44 6.67 24 26 9.37 .89 1.20 .24 .10 .29 8.78 26 27 9.71 .97 1.37 .18 .12 .35 9.99 27 30 8.61 .37 .42 .28 .04 .10 10.78 30 31 10.00 1.53 2.27 .06 .19 .59 12.32 31 34 7.07 .38 .46 .34 .04 .10 10.20 36 37 6.05 1.09 1.75 .09 .15 .46 7.81 40 41 5.59 .75 1.14 .19 .10 .29 2.87 44 45 3.85 .44 .68 .14 .06 .17 1.18 50 52 5.00 1.34 1.99 .36 .16 .48 1.16 54 56 3.80 .60 .96 .09 .08 .25 .41 60 62 4.35 1.32 2.03 .24 .13 .39 .39 64 66 8.25 2.72 4.28 .41 .13 .40 .21 66 70 2.45 .22 .29 .38 .03 .06 .29 70 72 1.72 .96 1.88 .47 .15 .46 .37 80 82 1.49 .40 .74 .37 .06 .18 .08 84 86 2.24 .81 1.48 .21 .12 .39 .06 
Table A3 65

Musky Bay core (MB-1A)

3 4 12.41 1.16 1.71 -.01 -.14 .43 4.23 5 6 10.66 1.18 1.73 .10 .14 .42 4.94 7 8 10.39 1.07 1.69 .34 .15 .43 5.47 8 9 13.26 1.92 2.53 .27 .20 .63 5.77 

26 27 7.07 .96 1.26 .45 .10 .30 9.24 44 45 4.16 .68 1.00 .46 .09 .26 .54 

Northeastern Bay core

0 1 19.01 2.40 2.78 1.04 .22 .64 4.63 2 3 14.53 1.94 2.21 .92 .18 .52 3.17 4 5 14.63 2.14 2.46 .87 .20 .58 3.28 6 7 11.81 1.63 1.95 1.01 .16 .44 2.86 8 9 13.71 1.97 2.35 .71 .19 .56 3.30 

10 11 12.72 2.33 2.98 .94 .25 .75 3.83 12 13 14.52 1.73 1.97 .90 .16 .45 4.09 14 15 11.23 1.55 1.87 1.00 .15 .42 3.37 15 16 11.24 .82 .94 .55 .08 .21 4.90 16 17 1.84 .50 .73 .33 .05 .14 .48 18 19 1.25 .49 .77 .56 .07 .17 .36 20 21 1.15 .43 .69 .49 .06 .15 .41 22 23 1.61 .73 1.17 .74 .10 .27 .62 24 25 2.10 .55 .87 .48 .08 .22 .58 26 27 1.50 .67 1.09 .63 .09 .25 .42 28 29 .84 .57 .98 .60 .08 .23 .30 29 30 1.22 .60 .99 .65 .08 .23 .16 

Table A3. Results from analysis of 210Pb, 226Ra, and 137Cs from core samples from Musky Bay and Northeastern Bay, Lac Courte Orei

Continued

Top

interval

(cm)

Bottom

interval

(cm)

Total 210Pb 

activity

(pCi g-1)

 Total 210Pb 

Uncertainty

(pCi g-1)

 Total 210Pb 

LLD

(pCi g-1)

226Ra

activity

(pCi g-1)

226Ra 

Uncertainty

(pCi g-1)

226Ra 

LLD

(pCi g-1)

137Cs 

activity

(pCi g-1)
66 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentratio

tantalum were less than 1 ppm [cm, centimeters; %, percent; ppm, parts per million; --, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combi

through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, no

dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS corer, an

Field no. Date collected Top interval (cm) Bottom interval (cm) Average depth (cm) Al (%) Sb (ppm) As (ppm) Ba (ppm) Be (ppm) Cd (ppm) Ca (%) Ce (ppm) Cr (ppm) Co (ppm) Cu (ppm) E

(pp

MB-1-1 10/12/99 0 2 1.0 0.73 0.23 3.0 90 0.23 60 0.81 6.8 17 2.2 51 <MB-1-3 10/12/99 2 3 2.5 .69 .23 2.8 97 .27 23 .77 8.3 11 2.3 22 <MB-1-5 10/12/99 4 5 4.5 .77 .26 3.1 95 .3 5.8 .67 9.6 12 2.4 20 <MB-1-7 10/12/99 6 7 6.5 .90 .31 3.6 99 .43 3.1 .65 10 14 2.7 23 <MB-1-10 10/12/99 9 10 9.5 .90 .38 3.8 110 .27 2.5 .68 12 15 2.6 28 <MB-1-13 10/12/99 12 13 12.5 .84 .35 3.7 110 .33 1.2 .60 11 14 2.5 18 <MB-1-16 10/12/99 15 16 15.5 .95 .42 4.9 120 .32 1.6 .66 12 15 2.7 30 <MB-1-19 10/12/99 18 19 18.5 .88 .36 4.6 130 .39 1.1 .63 12 14 2.6 32 <MB-1-22 10/12/99 21 22 21.5 1.0 .48 5.5 140 .18 1.2 .65 12 16 2.9 28 <MB-1-25 10/12/99 24 25 24.5 1.0 .50 5.7 150 .46 1.1 .60 14 15 2.8 25 <MB-1-28 10/12/99 27 28 27.5 1.0 .46 5.9 140 .40 1.2 .60 15 16 3.0 24 <MB-1-31 10/12/99 30 31 30.5 1.0 .63 6.1 150 .45 1.2 .62 15 17 3.0 23 <MB-1-34 10/12/99 33 34 33.5 1.1 .48 5.8 150 .45 1.3 .64 15 17 3.2 35 <MB-1-QA-1 10/12/99 33 34 33.5 .94 .52 6.0 150 .43 1.3 .59 15 17 3.1 26 <MB-1-37 10/12/99 36 37 36.5 1.0 .50 6.4 160 .51 1.3 .64 15 16 3.1 21 <MB-1-41 10/12/99 40 41 40.5 .96 .49 6.4 160 .46 1.3 .63 15 16 3.0 20 <MB-1-QA-2 10/12/99 40 41 40.5 1.0 .36 6.6 170 .26 1.1 .78 14 13 2.4 17 <MB-1-46 10/12/99 45 46 45.5 .98 .45 6.2 170 .45 1.3 .62 16 16 2.9 15 <MB-1-51 10/12/99 50 52 51.0 1.0 .51 6.0 180 .51 1.2 .66 16 18 2.8 14 <MB-1-56 10/12/99 60 62 61.0 .88 .38 6.5 170 .34 1.2 .68 14 15 2.6 11 <MB-1-61 10/12/99 70 72 71.0 .86 .31 6.1 170 .24 1.1 .67 14 15 2.5 13 <MB-1-QA-3 10/12/99 70 72 71.0 1.2 .48 5.9 160 .33 1.3 .74 15 16 2.9 29 <
Table A4 67

MB-1-68 10/12/99 84 86 85.0 .77 .32 6.1 170 .26 .94 .65 14 14 2.3 12 <MB-3-1 10/12/99 0 2 1.0 1.0 .27 3.2 140 .23 14 .84 11 18 2.6 18 <MB-4-1 07/24/01 0 2 1.0 1.0 .37 4.6 120 .27 .79 .80 11 2.8 2.7 21 <MB-5-1 07/25/01 0 2 1.0 1.2 .38 9.1 220 .40 .74 .80 17 9.8 5.6 34 <LCO-1-1 10/13/99 0 1 .5 1.8 .84 12 260 .49 20 .84 25 36 7.7 35 <LCO-1-3 10/13/99 2 3 2.5 1.6 .61 11 250 .72 1.3 .79 26 34 7.6 29 <LCO-1-5 10/13/99 4 5 4.5 1.6 .55 12 240 .60 1.2 .78 26 34 7.1 27 <LCO-1-7 10/13/99 6 7 6.5 1.8 .61 14 260 .71 1.2 .77 28 35 7.6 30 <LCO-1-9 10/13/99 8 9 8.5 1.7 .58 13 260 .64 1.1 .76 28 34 7.8 27 <LCO-1-11 10/13/99 10 11 1.5 1.8 .63 13 260 .58 1.2 .76 28 34 7.6 28 <LCO-1-13 10/13/99 12 13 12.5 1.8 .67 15 260 .46 1.2 .74 30 33 7.5 29 <LCO-1-QA-1 10/13/99 12 13 12.5 1.8 .70 15 250 .76 1.4 .72 29 34 7.5 41 <LCO-1-15 10/13/99 14 15 14.5 1.9 .74 15 270 .66 1.3 .74 31 35 7.7 30 <LCO-1-17 10/13/99 16 17 16.5 2.2 .74 15 290 .61 1.3 .74 31 38 7.8 29 <LCO-1-19 10/13/99 18 19 18.5 2.1 .65 10 290 .54 .88 .75 29 32 6.5 19 <LCO-1-21 10/13/99 20 21 20.5 1.9 .30 5.2 270 .49 .29 .58 22 26 4.4 13 <LCO-1-23 10/13/99 22 23 22.5 1.8 .29 5.7 240 .53 .26 .63 26 28 4.8 15 <LCO-1-QA-2 10/13/99 22 23 22.5 1.7 .22 6.5 240 .40 .31 .66 26 28 5.4 16 <LCO-1-25 10/13/99 24 25 24.5 1.9 .21 3.7 270 .36 .16 .56 21 24 4.1 11 <LCO-1-27 10/13/99 26 27 26.5 1.9 .22 4.7 230 .52 .20 .56 24 28 4.6 15 <LCO-1-29 10/13/99 28 29 28.5 1.9 .26 5.7 210 .66 .21 .49 26 29 4.7 18 <LCO-3-1 07/25/01 0 2 1.0 1.5 .46 12 320 .49 .99 1.0 23 18 6.7 26 <

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentratio

tantalum were less than 1 ppm—Continued

[cm, centimeters; %, percent; ppm, parts per million; --, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combi

through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, no

dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS corer, an

Field no. Date collected Top interval (cm) Bottom interval (cm) Average depth (cm) Al (%) Sb (ppm) As (ppm) Ba (ppm) Be (ppm) Cd (ppm) Ca (%) Ce (ppm) Cr (ppm) Co (ppm) Cu (ppm) E

(pp
68 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores SB-1-1 10/13/99 0 1 .5 1.7 .48 9.9 240 .45 14 .72 17 32 6.1 40 <

SB-1-2 10/13/99 1 2 1.5 1.5 .45 7.5 220 .43 3.6 .55 15 30 5.3 32 <SB-2-1 07/25/01 0 2 1.0 1.0 .30 5.9 230 .25 .58 .74 12 6.1 4.5 40 <SAN-1-1 07/25/01 0 2 1.0 1.3 .16 2 250 .22 <.1 .17 16 1.5 <1 3.2 <DEV-1-1 07/25/01 0 2 1.0 3.4 .31 3 340 .74 .42 .98 35 30 6.2 33 <ASH-1-1 07/25/01 0 2 1.0 2.2 .19 1.4 360 .54 .10 .35 21 9.6 2.0 9.7 <WET-1-1 08/14/01 0 2 1.0 .42 .21 1.9 99 <.1 .54 .30 6.0 <1 1.5 10 <LEV-1-1 09/27/01 0 2 1.0 2.2 .56 2.1 300 .41 .15 .53 20 21 4.5 13 <JON-1-1 07/24/01 0 10 5.0 2.1 .20 2.1 240 .5 .11 .64 21 19 4.3 83 <JON-1-2 07/24/01 0 10 5.0 2.2 .18 2.6 250 .54 <.1 .72 21 26 4.6 67 <ZAW-1-1 07/24/01 0 8 4.0 1.9 .20 1.6 240 .44 <.1 .56 20 14 4.2 17 <JON-2-1 07/24/01 na na na .32 .46 3.9 11 1.2 1.2 .97 3.1 22 1.0 320 <JON-3-1 07/24/01 na na na .88 2.4 13 45 2.9 4.6 12 70 70 6.1 5.9 

W-Blank 05/09/01 na na na .054 <.1 <.1 9.3 <.1 1.2 <.005 <1 <1 <1 <1 <

Blank 05/09/01 na na na .055 <.1 <.1 7.5 <.1 <.1 <.005 <1 2 <1 <1 <

U-Blank 05/09/01 na na na .058 <.1 .11 8.8 <.1 <.1 <.005 <1 <1 <1 <1 <

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentratiotantalum were less than 1 ppm—Continued [cm, centimeters; %, percent; ppm, parts per million; --, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combin

through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, no

dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS corer, an

Field no. Date collected Top interval (cm) Bottom interval (cm) Average depth (cm) Al (%) Sb (ppm) As (ppm) Ba (ppm) Be (ppm) Cd (ppm) Ca (%) Ce (ppm) Cr (ppm) Co (ppm) Cu (ppm) E

(pp
Table A4 69

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentrat

tantalum were less than 1 ppm—Continued

[cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, co

passed through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized 

and oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USG

Field no.

Average

depth 

(cm)

La 

(ppm)

Pb 

(ppm)

Li 

(ppm)

Mg

(%)

Mn 

(ppm)

Mo 

(ppm)

No 

(ppm)

Ni 

(ppm)

Nb 

(ppm)

P

(%)

K

(%)

Sc 

(ppm)

Ag 

(ppm)

Na

(%)

S

(pp

MB-1-1 1.0 3.6 18 3.5 0.20 260 0.64 3.2 9.8 <4 0.35 0.32 <2 <.1 0.08 

MB-1-3 2.5 4.2 20 3.4 .18 220 .61 3.7 6.7 <4 .30 .27 <2 <.1 .08 

MB-1-5 4.5 5.0 24 4.2 .18 220 .69 4.3 7.0 <4 .22 .24 <2 <.1 .07 

MB-1-7 6.5 5.1 30 4.8 .19 230 .82 4.8 7.9 <4 .18 .24 2.1 <.1 .09 

MB-1-10 9.5 6.0 34 5.1 .18 250 1.1 5.1 8.2 <4 .16 .25 2.2 <.1 .09 

MB-1-13 12.5 5.6 36 4.7 .16 260 .85 5.0 7.5 <4 .13 .23 2.0 <.1 .08 

MB-1-16 15.5 6.1 49 5.0 .18 290 .95 5.5 8.2 <4 .12 .25 2.0 <.1 .10 

MB-1-19 18.5 6.4 52 5.1 .17 290 .91 5.6 8.3 <4 .10 .24 <2 <.1 .10 

MB-1-22 21.5 6.5 57 5.8 .18 320 1.0 5.8 9.1 <4 .098 .28 2.1 <.1 .11 

MB-1-25 24.5 7.3 59 5.7 .18 290 .94 6.5 8.5 <4 .090 .27 2.0 <.1 .11 

MB-1-28 27.5 7.7 48 6.0 .18 310 .83 6.8 8.9 <4 .081 .28 2.1 <.1 .11 

MB-1-31 30.5 8.6 44 6.2 .18 320 .85 7.1 8.7 <4 .080 .29 2.2 <.1 .11 

MB-1-34 33.5 7.6 42 6.1 .18 340 .88 7.1 9.2 <4 .083 .29 2.3 <.1 .11 

MB-1-QA-1 33.5 8.0 41 5.8 .16 330 .97 7.1 8.9 <4 .075 .26 2.0 <.1 .10 

MB-1-37 36.5 7.6 38 6.0 .18 340 .98 6.8 9.0 <4 .074 .29 2.1 <.1 .12 

MB-1-41 40.5 7.7 36 5.7 .17 360 .87 7.1 8.9 <4 .071 .28 2.1 <.1 .11 

MB-1-QA-2 40.5 7.3 23 5.7 .21 390 .92 6.7 7.9 <4 .085 .28 2.5 <.1 .13 

MB-1-46 45.5 8.0 51 5.8 .17 360 .88 7.3 8.6 <4 .066 .29 2.2 <.1 .12 

MB-1-51 51.0 8.2 36 5.8 .18 390 .84 7.4 8.7 <4 .066 .29 2.2 <.1 .12 

MB-1-56 61.0 7.2 24 4.9 .18 400 .80 6.6 8.7 <4 .066 .26 2.1 <.1 .12 

MB-1-61 71.0 7.1 24 5.1 .18 410 .75 6.5 8.1 <4 .067 .25 2 <.1 .11 

MB-1-QA-3 71.0 7.5 34 6.3 .21 350 .88 7.0 9.1 <4 .086 .30 2.6 <.1 .13 
70 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores MB-1-68 85.0 7.4 22 4.4 .16 400 .82 6.5 7.4 <4 .065 .23 <2 <.1 .10 

MB-3-1 1.0 5.7 36 4.8 .21 360 .59 5.0 9.5 <4 .18 .34 2.2 <.1 .15 

MB-4-1 1.0 5.5 39 4.4 .22 200 .96 5.6 8.4 <4 .23 .29 2.1 <.1 .11 MB-5-1 1.0 8.4 28 5.4 .24 1,200 1.2 9.3 12 <4 .095 .32 3.6 <.1 .17 

LCO-1-1 .5 12 58 8.5 .31 1,900 .90 12 16 4.3 .10 .58 5.3 <.1 .28 4

LCO-1-3 2.5 12 46 8.9 .30 2,100 .92 13 15 4.1 .12 .48 5.2 <.1 .24 4LCO-1-5 4.5 12 50 8.5 .29 1,800 .94 12 15 4.0 .11 .47 5.2 <.1 .23 LCO-1-7 6.5 13 56 9.1 .31 1,800 1.0 14 16 4.9 .11 .53 5.5 <.1 .26 4LCO-1-9 8.5 13 57 9.2 .30 1,800 1.0 13 15 4.1 .10 .52 5.4 <.1 .25 4LCO-1-11 10.5 14 63 9.2 .31 1,700 .99 14 16 4.2 .098 .53 5.6 <.1 .26 4LCO-1-13 12.5 14 67 9.1 .31 1,500 1.1 14 16 4.6 .084 .57 5.5 <.1 .27 4LCO-1-QA-1 12.5 14 68 9.4 .31 1,600 1.1 14 16 4.6 .082 .52 5.3 <.1 .25 4LCO-1-15 14.5 15 68 9.6 .32 1,300 1.2 14 16 5.1 .078 .60 5.7 <.1 .28 4LCO-1-17 16.5 16 50 9.8 .33 970 1.3 15 17 5.8 .064 .75 5.9 <.1 .36 

LCO-1-19 18.5 14 24 8.1 .32 760 .90 15 14 5.5 .045 .94 5.3 <.1 .41 

LCO-1-21 20.5 12 9.0 6.3 .25 430 <.5 11 10 4.4 .024 1.0 4.1 <.1 .41 LCO-1-23 22.5 12 8.0 6.2 .26 520 .63 13 12 4.6 .027 .86 4.5 <.1 .39 

LCO-1-QA-2 22.5 14 8.5 6.5 .28 570 .68 13 12 4.2 .03 .82 4.6 <.1 .38 

LCO-1-25 24.5 11 6.3 6.1 .24 340 <.5 11 9.0 4.7 .02 1.0 3.8 <.1 .43 

LCO-1-27 26.5 12 6.6 7.6 .26 450 .85 12 11 4.7 .026 .84 4.4 <.1 .36 

LCO-1-29 28.5 14 6.4 9.4 .28 550 1.6 13 12 5 .024 .65 4.5 <.1 .25 4

LCO-3-1 1.0 11 50 7.6 .33 3,300 .65 12 14 <4 .14 .43 4.7 <.1 .21 4

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentrati

tantalum were less than 1 ppm—Continued [cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, co

passed through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized and oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USG

Field no. Average depth (cm) La (ppm) Pb (ppm) Li (ppm) Mg (%) Mn (ppm) Mo (ppm) No (ppm) Ni (ppm) Nb (ppm)

P

(%)

K

(%)

Sc 

(ppm)

Ag 

(ppm)

Na

(%)

S

(pp
Table A4 71

SB-1-1 .5 8.4 45 7.3 .29 2,000 .77 7.6 16 < 4 .10 .45 3.7 <.1 .22 45 

SB-1-2 1.5 7.5 41 6.3 .24 1,400 .71 6.6 15 < 4 .079 .42 3.1 <.1 .21 41 

SB-2-1 1.0 5.6 21 4.4 .20 1,600 .77 6.0 9.8 <4 .12 .24 2.4 <.1 .11 26 

SAN-1-1 1.0 8.5 5 2.9 .05 100 <.5 8.2 <2 <4 .013 1.1 <2 <.1 .21 37 

DEV-1-1 1.0 18 21 12 .47 180 .64 18 2.0 8.6 .13 1.1 6.3 .14 .62 100 ASH-1-1 1.0 12 11 5.2 .15 140 <.5 11 5.8 6.5 .019 1.4 2.8 .10 .45 70 

WET-1-1 1.0 2.9 19 1.3 .11 170 <.5 2.7 4.1 <4 .12 .14 <2 <.1 .04 17 

LEV-1-1 1.0 11 27 7.0 .35 230 <.5 10 10 5 .040 1.0 4.4 <.1 .42 59 JON-1-1 5.0 11 8.9 5.0 .39 150 <.5 11 11 <4 .068 1.2 4.4 <.1 .43 52 JON-1-2 5.0 11 8.2 5.2 .44 160 <.5 11 13 <4 .065 1.2 4.6 <.1 .45 57 ZAW-1-1 4.0 10 5.1 5.2 .35 150 <.5 11 12 <4 .079 1.1 4.2 <.1 .40 53 

JON-2-1 na 2.6 11 1.5 .65 700 2.8 1.8 7.2 <4 6.9 1.0 2 <.1 .28 28 JON-3-1 na 47 8.8 2.9 .46 280 12 41 31 <4 23 3.1 7.6 <.1 .36 500 W-Blank na <1 <1 9.7 <.005 <4 <.5 <1 <2 <4 <.005 <.005 <2 <.1 <.005 <2 

Blank na <1 <1 11 <.005 <4 <.5 <1 <2 <4 <.005 <.005 <2 <.1 <.005 <2 U-Blank na <1 <1 10 <.005 <4 <.5 <1 <2 <4 <.005 <.005 <2 <.1 <.005 <2 

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentratio

tantalum were less than 1 ppm—Continued

[cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, com

passed through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized wand oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS 

Field no.

Average

depth 

(cm)

La 

(ppm)

Pb 

(ppm)

Li 

(ppm)

Mg

(%)

Mn 

(ppm)

Mo 

(ppm)

No 

(ppm)

Ni 

(ppm)

Nb 

(ppm)

P

(%)

K

(%)

Sc 

(ppm)

Ag 

(ppm)

Na

(%)

Sr 

(ppm
72 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentrations of bismuth, gold, and tantalum were less than 1 ppm—Continued [cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, not passed through corer, and oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS corer, and oven dried] Field no. Average depth (cm) Sn (ppm) Ti (%)

U

(ppm)

V 

(ppm)

Yb 

(ppm)

Y 

(ppm) Zn (ppm)

MB-1-1 1.0 <1 0.031 0.36 11 <1 2.8 91

MB-1-3 2.5 <1 .033 .43 12 <1 3.1 69MB-1-5 4.5 <1 .037 .48 13 <1 3.4 64MB-1-7 6.5 <1 .042 .50 16 <1 4.0 68MB-1-10 9.5 1.4 .047 .56 16 <1 4.3 71MB-1-13 12.5 1.0 .044 .55 15 <1 4.0 70MB-1-16 15.5 1.2 .046 .63 17 <1 4.4 87MB-1-19 18.5 1.2 .045 .60 17 <1 4.5 99MB-1-22 21.5 1.2 .045 .67 20 <1 5.0 100MB-1-25 24.5 1.4 .052 .70 18 <1 5.2 94MB-1-28 27.5 1.4 .053 .70 20 <1 5.6 96MB-1-31 30.5 1.4 .055 .75 21 <1 5.7 94MB-1-34 33.5 1.4 .052 .72 22 <1 5.7 99MB-1-QA-1 33.5 1.6 .052 .74 22 <1 6.0 94MB-1-37 36.5 1.3 .054 .72 22 <1 5.8 91MB-1-41 40.5 1.4 .051 .73 22 1 5.8 90MB-1-QA-2 40.5 <1.0 .057 .63 18 <1 5.4 72MB-1-46 45.5 1.1 .054 .75 21 1 6.0 85MB-1-51 51.0 1.0 .052 .72 21 <1 6.1 78MB-1-56 61.0 <1 .05 .65 19 <1 5.7 72MB-1-61 71.0 <1 .045 .65 18 <1 5.5 70MB-1-QA-3 71.0 1.0 .057 .69 22 <1 5.8 91
Table A4 73

MB-1-68 85.0 <1 .045 .63 17 <1 5.3 65

MB-3-1 1.0 1.4 .051 .53 18 < 1 4.9 90 MB-4-1 1.0 1.8 .051 1.0 17 <1 3.8 100MB-5-1 1.0 1.8 .089 .88 44 <1 7.5 120LCO-1-1 .5 1.7 .13 1.2 51 1.7 13.0 110LCO-1-3 2.5 1.6 .12 1.2 51 1.6 13.0 100LCO-1-5 4.5 1.6 .11 1.2 49 1.6 12.0 100LCO-1-7 6.5 1.8 .13 1.3 53 1.9 14.0 110LCO-1-9 8.5 2.1 .12 1.3 52 1.7 13.0 100LCO-1-11 10.5 1.9 .13 1.4 52 1.9 13.0 110LCO-1-13 12.5 2.1 .13 1.5 54 1.8 13.0 110LCO-1-QA-1 12.5 2.0 .13 1.5 54 1.8 14.0 130LCO-1-15 14.5 2.3 .14 1.5 55 2.0 14.0 120LCO-1-17 16.5 2.2 .16 1.6 56 2.1 14.0 110LCO-1-19 18.5 1.2 .16 1.4 48 2.0 14.0 68LCO-1-21 20.5 <1 .14 1.0 33 1.8 12.0 31LCO-1-23 22.5 <1 .15 1.2 37 1.9 13.0 28LCO-1-QA-2 22.5 <1 .13 1.2 39 1.8 12.0 31LCO-1-25 24.5 <1 .14 .96 30 1.6 11.0 20LCO-1-27 26.5 <1 .13 1.3 37 1.8 12.0 25LCO-1-29 28.5 <1 .11 1.7 43 1.7 11.0 29LCO-3-1 1.0 2.5 .12 1.0 46 1.0 10.0 97

Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentrations of bismuth, gold, and tantalum were less than 1 ppm—Continued[cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz(150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through 

WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, not passed through corer, and oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized 

water, passed through USGS corer, and oven dried]

Field no.

Average

depth 

(cm)

Sn 

(ppm)

Ti

(%)

U

(ppm)

V 

(ppm)

Yb 

(ppm)

Y 

(ppm) Zn (ppm)
74 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores SB-1-1 .5 2.8 .096 .95 44 < 1 9.1 130 SB-1-2 1.5 2.4 .087 .86 38 < 1 7.8 99 SB-2-1 1.0 1.7 .06 .79 27 <1 4.6 85 SAN-1-1 1.0 1.0 .062 .61 7.6 <1 6.4 6.2 DEV-1-1 1.0 2.2 .32 1.6 59 1.4 12.0 130 ASH-1-1 1.0 1.5 .29 .82 20 1.1 8.6 24 WET-1-1 1.0 1.7 .025 .19 8.2 <1 1.6 52 LEV-1-1 1.0 1.8 .21 .89 36 1.1 8.6 42 JON-1-1 5.0 1.3 .14 1.7 37 1.1 9.0 28 JON-1-2 5.0 1.3 .15 1.5 36 1.0 8.6 26 ZAW-1-1 4.0 1.2 .13 1.3 33 1.1 9.4 19 JON-2-1 na 1.9 .0087 50 44 1.6 15.0 1600 JON-3-1 na 1.2 .056 190 170 7 97.0 62 W-Blank na <1 <.005 <.1 <2 <1 <1 <2 Blank na <1 <.005 <.1 <2 <1 <1 <2 U-Blank na <1 <.005 <.1 <2 <1 <1 <2 Table A4. Results of geochemical analysis of core samples from Lac Courte Oreilles and surrounding areas, 1999–2001. All concentrations of bismuth, gold, and tantalum were less than 1 ppm—Continued [cm, centimeters; %, percent; ppm, parts per million; na, no data; W-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through WDNR corer, and oven dried; Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, not passed through corer, and oven dried; U-Blank, fine grained abrasive quartz (150 micrometers) from USGS Geologic Division laboratory, combined with deionized water, passed through USGS corer, and oven dried] Field no. Average depth (cm) Sn (ppm) Ti (%)

U

(ppm)

V 

(ppm)

Yb 

(ppm)

Y 

(ppm) Zn (ppm)
Table A5 75

Table A5. Results from nutrients analysis of core samples from Musky and Northeastern Bays, 

Lac Courte Oreilles, October 1999

[cm, centimeter]

Sample ID

Top

interval

(cm) 

Bottom

interval

(cm)

Organic carbon 

(percent)

Nitrogen 

(percent)

Musky Bay core

MB-1-1 0 2 24.7 3.61

MB-1-3 2 3 24.4 3.39

MB-1-5 4 5 24.3 3.43

MB-1-7 6 7 24.3 3.07

MB-1-10 9 10 23.9 3.09

MB-1-13 12 13 24.0 2.96

MB-1-16 15 16 22.2 2.65

MB-1-QA1 15 16 24.8 3.20

MB-1-19 18 19 22.9 2.68

MB-1-22 21 22 22.1 2.57

MB-1-25 24 25 22.1 2.57

MB-1-28 27 28 21.2 2.33

MB-1-31 30 31 22.1 2.53

MB-1-QA2 30 31 22.2 2.57

MB-1-34 33 34 22.9 2.46

MB-1-37 36 37 23.4 2.53

MB-1-41 40 41 23.0 2.51

MB-1-46 45 46 23.8 2.64

MB-1-QA3 45 46 23.5 2.57

MB-1-51 50 52 23.9 2.57

MB-1-56 60 62 27.1 2.78

MB-1-61 70 72 26.6 2.79

MB-1-68 84 86 27.1 2.82
76 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Northeastern Bay core

LCO-1-1 0 1 19.4 2.20

LCO-1-3 2 3 19.9 2.22

LCO-1-5 4 5 18.7 2.00

LCO-1-7 6 7 19.9 2.05

LCO-1-9 8 9 20.5 2.12

LOC-1-QA1 8 9 18.8 2.03

LCO-1-11 10 11 18.4 2.02

LCO-1-13 12 13 17.8 1.89

LCO-1-15 14 15 18.4 1.99

LCO-1-17 16 17 15.3 1.65

LCO-1-19 18 19 17.5 1.71

LCO-1-QA2 18 19 17.6 1.85

LCO-1-21 20 21 15.9 1.43

LCO-1-23 22 23 18.9 1.64

LCO-1-25 24 25 13.3 1.06

LCO-1-27 26 27 11.1 1.03

LCO-1-29 28 29 12.8 1.20

Table A5. Results from nutrients analysis of core samples from Musky and Northeastern Bays, 

Lac Courte Oreilles, October 1999—Continued

[cm, centimeter]

Sample ID

Top

interval

(cm) 

Bottom

interval

(cm)

Organic carbon 

(percent)

Nitrogen 

(percent)
Table A6 77

Table A6. Results from biogenic silica analysis of core samples from Musky 

and Northeastern Bays, Lac Courte Oreilles, October 1999

[cm, centimeter]

Sample ID

Top

interval

(cm)

Bottom

interval

(cm)

Biogenic silica 

(weight percent)

Musky Bay core

MB-1-1 0 2 32.1

MB-1-3 2 3 29.7

MB-1-5 4 5 28.7

MB-1-7 6 7 27.5

MB-1-10 9 10 27.0

MB-1-13 12 13 26.2

MB-1-16 15 16 25.0

MB-1-QA1 15 16 23.6

MB-1-19 18 19 24.7

MB-1-22 21 22 25.0

MB-1-25 24 25 20.4

MB-1-28 27 28 32.7

MB-1-31 30 31 22.9

MB-1-QA2 30 31 22.8

MB-1-34 33 34 26.0

MB-1-37 36 37 22.9

MB-1-41 40 41 21.1

MB-1-46 45 46 23.1

MB-1-QA3 45 46 20.4

MB-1-51 50 52 17.3

MB-1-56 60 62 18.5

MB-1-61 70 72 16.4

MB-1-68 84 86 15.5
78 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Northeastern Bay core

LCO-1-1 0 1 18.9

LCO-1-3 2 3 23.8

LCO-1-5 4 5 24.8

LCO-1-7 6 7 28.7

LCO-1-9 8 9 24.5

LCO-1-11 10 11 26.1

LOC-1-QA1 10 11 27.0

LCO-1-13 12 13 26.6

LCO-1-15 14 15 28.3

LCO-1-17 16 17 26.4

LCO-1-19 18 19 17.4

LCO-1-21 20 21 5.4

LCO-1-QA2 20 21 6.8

LCO-1-23 22 23 14.2

LCO-1-25 24 25 9.7

LCO-1-27 26 27 5.7

LCO-1-29 28 29 24.6

Table A6. Results from biogenic silica analysis of core samples from Musky 

and Northeastern Bays, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter]

Sample ID

Top

interval

(cm)

Bottom

interval

(cm)

Biogenic silica 

(weight percent)
Table A7 79

Table A7. Results from analysis of diatom valve concentration

from Musky and Northeastern Bays, Lac Courte Oreilles, October 

1999

[cm, centimeter; g, gram]

Top

interval

(cm)

Bottom

interval

(cm)

Diatom counts,

in valves (x108) g-1, 

dry weight

Musky Bay core

0 1 32.2

5 6 32.3

10 11 100.4

11 12 39.2

15 16 44.2

20 21 26.7

30 31 88.6

40 41 3.7

45 46 33.7

50 52 7.5

60 62 15.3

62 64 28.6

64 66 36.2

66 68 39.2

Northeastern Bay core

0 1 7.9

10 11 24.7

16 17 10.0

24 25 8.1

40 41 7.7
80 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 7–8 cm

Achnanthidium minutissima + vars. 1 1 0.006

Amphora ovalis 1 0 .003

Amphora perpusilla 2 0 .006

Cocconeis placentula var. lineata 2 0 .006

Cocconeis placentula (RV) 1 2 .009

Cyclotella ocellata 0 1 .003

Cymbella angustata 0 1 .003

Cymbella cymbiformis var. nonpunctata 1 0 .003

Cymbella subaequalis 1 0 .003

Encyonema silesiacum 0 1 .003

Epithemia arcus 1 0 .003

Epithemia sp. 1 1 .006

Epithemia turgida 0 2 .006

Eunotia pectinalis 1 .5 .004

Fragilaria capucina + vars. 16 3 .054

Gomphonema acuminatum 1 0 .003

Gomphonema tenellum 2 0 .006

Gomphonema (GV) 0 2 .006

Gomphonema sp. 0 1 .003

Navicula atomus var. permitis 1 2 .009

Navicula lanceolata 0 1 .003

Navicula minima 1 0 .003

Navicula pseudoventralis 2 1 .009

Navicula (GV) (short) 2 0 .006

Navicula sp. 0 2 .006

Nitzschia amphibia 1 0 .003

Nitzschia sp. 0 2 .006

Pseudostaurosira brevistrata + vars. 8 31 .112

Staurosira construens 41 67 .309

Staurosira construens var. binodis 6 4 .029

Staurosira construens var. venter 32 31 .180

Staurosira elliptica 2 1 .009

Staurosirella leptostauron var. dubia 0 3 .009

Staurosirella pinnata 33 23 .160

Synedra sp. 0 1 .003

Unknown (raphid) 1 0 .003

Unknown 1 1 .006

TOTAL 163 186.5 1.000

3

Chrysophyte cysts 1 1

Scenedesmus coenobia 0 2
Table A8 81

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 10–11 cm

Achnanthidium minutissima + vars. 2 6 0.025

Amphora ovalis 0 1 .003

Aulacoseira ambigua 0 2 .006

Cocconeis placentula var. lineata 0 5 .016

Encyonema silesiacum 1 0 .003

Epithemia sp. 0 1 .003

Epithemia turgida 2 0 .006

Eunotia incisa 0 .5 .002

Fragilaria capucina + vars. 8 4 .037

Fragilaria crotonensis 6 0 .019

Fragilaria cf. oldenburgiana 0 2 .006

Gomphonema tenellum 1 0 .003

Gomphonema truncatum 1 1 .006

Navicula atomus var. permitis 1 0 .003

Navicula lanceolata 1 0 .003

Navicula minima 2 2 .012

Navicula schadei 0 2 .006

Navicula (GV) (short) 2 0 .006

Navicula sp. 0 1 .003

Nitzschia amphibia 0 2 .006

Nitzschia sp. 2 0 .006

Pseudostaurosira brevistrata + vars. 23 11 .106

Staurosira construens 26 34 .187

Staurosira construens var. binodis 5 12 .053

Staurosira construens var. venter 38 50 .275

Staurosira elliptica 7 5 .037

Staurosirella pinnata 30 17 .147

Synedra ulna 1 0 .003

Unknown (raphid) 0 1 .003

Unknown 1 1 .006

TOTAL 160 160.5 1.000

3

Chrysophyte cysts 1 1

Scenedesmus coenobia 0 2
82 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 11–12 cm

Achnanthidium exiguum 1 0 0.003

Achnanthidium minutissima + vars. 2 2 .012

Amphora ovalis var. affinis 0 1 .003

Aulacoseira ambigua 3 0 .009

Aulacoseira italica 0 2 .006

Cocconeis placentula var. lineata 0 1 .003

Cocconeis placentula (RV) 1 2 .009

Cyclostephanos sp. 0 1 .003

Cyclotella glomerata 1 0 .003

Cyclotella sp. 0 1 .003

Cymbella cistula 1 0 .003

Cymbella sp. 1 1 .006

Epithemia arcus 1 0 .003

Epithemia sp. 2 1 .009

Epithemia turgida 1 5 .017

Eunotia incisa .5 0 .001

Eunotia pectinalis .5 0 .001

Eunotia sp. .5 0 .001

Fragilaria capucina + vars. 14 10 .069

Gomphonema sp. 0 2 .006

Navicula atomus var. permitis 3 3 .017

Navicula cryptotenella 1 0 .003

Navicula minima 1 0 .003

Navicula (GV) (short) 2 0 .006

Navicula sp. 4 2 .017

Nitzschia amphibia 0 2 .006

Nitzschia sp. 1.5 0 .004

Pseudostaurosira brevistrata + vars. 30 29 .171

Sellaphora rectangularis 0 1 .003

Stauroneis sp. 0 1 .003

Staurosira construens 56 33 .257

Staurosira construens var. binodis 9 22 .090

Staurosira construens var. venter 13 31 .127

Staurosira elliptica 2 5 .020

Staurosirella pinnata 20 14 .098

Unknown 2 0 .006

TOTAL 174 172 1.000

3

Chrysophyte cysts 1 0

Zooplankton parts 0 1
Table A8 83

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 17–18 cm

Achnanthidium exiguum 0 1 0.003

Achnanthidium minutissima + vars. 1 5 .015

Cocconeis placentula var. lineata 4 3 .018

Cocconeis placentula 1 0 .003

Cocconeis placentula (RV) 0 3 .008

Cyclotella michiganiana 1 0 .003

Cyclotella ocellata 0 2 .005

Cymbella angustata 2 0 .005

Cymbella cistula 1 0 .003

Cymbella sp. 1 0 .003

Encyonema silesiacum 0 2 .005

Epithemia turgida 0 1 .003

Eunotia incisa 0 1 .003

Eunotia rhomboides 0 1 .003

Fragilaria capucina + vars. 27 3 .076

Fragilaria crotonensis 4 0 .010

Gomphonema sp. 1 0 .003

Navicula atomus var. permitis 1 2 .008

Navicula cryptotenella 0 1 .003

Navicula lanceolata 0 1 .003

Navicula minima 0 2 .005

Navicula pelliculosa 2 2 .010

Navicula pseudoventralis 2 6 .020

Navicula tripunctata 0 1 .003

Navicula (GV) (short) 2 2 .010

Navicula sp. 1 2 .008

Nitzschia amphibia 3 0 .008

Nitzschia sp. 0.5 2 .006

Planothidium lanceolata 1 0 .003

Pseudostaurosira brevistrata + vars. 24 32 .143

Staurosira construens 33 34 .171

Staurosira construens var. binodis 1 7 .020

Staurosira construens var. subsalina 0 1 .003

Staurosira construens var. venter 46 35 .206

Staurosira elliptica 2 7 .023

Staurosirella leptostauron var. dubia 1 0 .003

Staurosirella pinnata 20 44 .163

Synedra fasciculata 0 1 .003

Synedra minuscula 2 0 .005

Synedra rumpens var. familaris 0 3 .008

Unknown (raphid) 1 0 .003

TOTAL 185.5 207 1.000

3

Chrysophyte cysts 0 0

Scenedesmus coenbia 0 0

Tetraedron coenbia 0 1

Sponge spicules 0 1
84 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 20–21 cm

Achnanthes minutissima + vars. 2 4 0.013

Amphora ovalis var. affinis 1 0 .002

Amphora perpusilla 0 1 .002

Aulacoseira (VV) 0 1 .002

Cocconeis placentula (RV) 3 0 .006

Cyclotella glomerata 0 1 .002

Cymbella cistula 1 0 .002

Cymbella sp. 1 2 .006

Epithemia sorex 2 0 .004

Epithemia turgida 0 1 .002

Epithemia sp. 1 0 .002

Eunotia sp. 1 0 .002

Fragilaria capucina + vars. 0 8 .017

Fragilaria crotonensis 0 7 .015

Gomphonema acuminatum 0 1 .002

Gomphonema truncatum var. capitatum 0 3 .006

Gomphonema sp. 0 1 .002

Navicula atomus var. permitis 3 3 .013

Navicula glomus 0 2 .004

Navicula lanceolata 0 1 .002

Navicula minima 0 5 .011

Navicula pelliculosa 2 2 .008

Navicula pseudoventralis 0 3 .006

Navicula (GV) (short) 4 0 .008

Navicula sp. 1 0 .002

Nitzschia amphibia 0 3 .006

Nitzschia sp. 0 2 .004

Planothidium lanceolata 0 1 .002

Pseudostaurosira brevistrata + vars. 24 45 .145

Staurosira construens 42 43 .179

Staurosira contruens var. subsalina 0 1 .002

Staurosira construens var. binodis 13 27 .084

Staurosira construens var. venter 38 51 .187

Staurosira elliptica 7 10 .036

Staurosirella leptostauron var. dubia 1 0 .002

Staurosirella pinnata 18 81 .208

Synedra rumpens var. familaris 0 1 .002

Unknown (raphid) 1 2 .006

Unknown 4 0 .008

TOTAL 165 311 1.000

Chrysophyte cysts 0 1
Table A8 85

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 43–44 cm

Achnanthes exiguum 1 2 0.009

Achnanthes minutissima + vars. 21 18 .118

Aulacoseira ambigua 3 1 .012

Aulacoseira italica 4 0 .012

Cocconeis placentula var. lineata 3 0 .009

Cocconeis placentula (RV) 2 2 .012

Cyclotella glomerata 1 0 .003

Cymbella angustata 1 0 .003

Cymbella cistula 0 2 .006

Cymbella sp. 0 2 .006

Encyonema silesiacum 0 3 .009

Epithemia sp. 0 1 .003

Eunotia incisa .5 0 .002

Fragilaria capucina + vars. 2 12 .042

Fragilaria crotonensis 9 4 .039

Fragilaria radians 0 2 .006

Geissleria ignota var. palustris 0 2 .006

Gomphonema acuminatum 0 1 .003

Gomphonema affine var. insigne 2 0 .006

Gomphonema tenellum 1 0 .003

Gomphonema subtile 0 1 .003

Gomphonema (GV) 2 0 .006

Gomphonema sp. 1 1 .006

Navicula atomus var. permitis 7 4 .033

Navicula lanceolata 1 1 .006

Navicula minima 0 1 .003

Navicula pseudoventralis 2 1 .009

Navicula schadei 1 5 .018

Navicula sp. 2 2 .012

Nitzschia palea 1 0 .003

Pseudostaurosira brevistrata + vars. 25 8 .100

Stauroneis sp. 1 0 .003

Staurosira construens 22 21 .130

Staurosira construens var. binodis 0 10 .030

Staurosira construens var. venter 25 31 .169

Staurosira elliptica 5 3 .024

Staurosirella pinnata 21 25 .139

Stephanodiscus niagarae 0 1 .003

Stephanodiscus parvus 0 1 .003

Synedra acus 4 0 .012

Synedra rumpens var. familaris 5 0 .015

Unknown (raphid) 1 2 .009

Unknown 1 1 .006

TOTAL 166.5 164 1.000

3

Chrysophyte cysts 0 3

Zooplankton parts 0 1

Sponge spicules 1 1
86 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 46–47 cm

Achnanthes minutissima + vars. 7 27 0.103

Amphora ovalis var. affinis 0 2 .006

Asterionella formosa 0 2 .006

Aulacoseira ambigua 10 12 .067

Aulacoseira subarctica 0 2 .006

Aulacoseira (VV) 1 0 .003

Brachysira vitrea 0 1 .003

Cocconeis placentula var. lineata 2 1 .009

Cocconeis placentula (RV) 0 1 .003

Cyclotella michiganiana 4 0 .012

Cymbella angustata 2 0 .006

Encyonema silesiacum 0 2 .006

Epithemia arcus 4 2 .018

Epithemia turgida 0 1 .003

Eunotia sp. 2 0 .006

Fragilaria capucina + vars. 5 3 .024

Fragilaria oldenburgiana 0 2 .006

Fragilaria vaucheriae 1 0 .003

Geissleria ignota var. palustris 1 0 .003

Gomphonema parvulum 0 1 .003

Gomphonema tenellum 2 0 .006

Gomphonema subtile 0 1 .003

Gomphonema (GV) 4 2 .018

Navicula atomus var. permitis 8 3 .033

Navicula lanceolata 5 0 .015

Navicula minima 2 0 .006

Navicula pelliculosa 5 2 .021

Navicula pseudoventralis 6 1 .021

Navicula radiosa 0 2 .006

Navicula schadei 0 3 .009

Navicula (GV) (short) 2 0 .006

Navicula sp. 1 2 .009

Neidium affine var. amphirhynchus 0 1 .003

Neidium sp. 1 0 .003

Nitzschia sp. 2 0 .006

Pseudostaurosira brevistrata +vars. 22 17 .118

Sellaphora vitabunda 0 1 .003

Staurosira construens 17 24 .124

Staurosira construens var. venter 23 25 .145

Staurosira elliptica 10 0 .030

Staurosirella leptostauron var. dubia 0 2 .006

Staurosirella pinnata 11 10 .064

Synedra rumpens var. familaris 0 1 .003

Synedra sp. 0 3 .009

Tabellaria (GV) 1 2 .009

Unknown (raphid) 1 0 .003

Unknown 2 5 .021

TOTAL 164 166 1.000

Zooplankton parts 2 2

Sponge spicules 1 0
Table A8 87

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 47–48 cm

Achnanthes exiguum 0 1 0.003

Achnanthes minutissima + vars. 24 18 .111

Amphora ovalis 1 0 .003

Amphora ovalis var. affinis 0 2 .005

Asterionella formosa 1 0 .003

Aulacoseira ambigua 4 4 .021

Aulacoseira subarctica 3 0 .008

Brachysira vitrea 0 1 .003

Cocconeis placentula var. lineata 2 2 .011

Cocconeis placentula (RV) 0 2 .005

Cyclotella bodanica var. lemanica 0 1 .003

Cymbella cistula 4 1 .013

Cymbella sp. 2 0 .005

Encyonema silesiacum 3 0 .008

Epithemia arcus 0 1 .003

Epithemia sp. 1 0 .003

Epithemia turgida 1 0 .003

Eunotia pectinalis 1.5 0 .004

Fragilaria capucina + vars. 2 16 .048

Fragilaria crotonensis 0 3 .008

Fragilaria vaucheriae 2 0 .005

Geissleria ignota var. palustris 2 0 .005

Gomphonema tenellum 2 1 .008

Gomphonema truncatum 0 1 .003

Gomphonema (GV) 3 2 .013

Gomphonema sp. 1 2 .008

Navicula atomus var. permitis 4 7 .029

Navicula lanceolata 1 3 .011

Navicula pelliculosa 3 1 .011

Navicula pseudoventralis 1 2 .008

Navicula schadei 3 0 .008

Navicula (GV) (short) 20 2 .058

Navicula sp. 7 4 .029

Neidium sp. 1 0 .003

Nitzschia sp. 0 2 .005

Pinnularia sp. 0 1 .003

Pseudostaurosira brevistrata + vars. 1 5 .016

Rhopalodia gibba 0 .5 .001

Sellaphora pupula 1 0 .003

Sellaphora rectangularis 1 0 .003

Sellaphora vitabunda 0 1 .003

Staurosira construens 40 17 .151

Staurosira construens var. binodis 6 5 .029

Staurosira construens var. subsalina 0 1 .003

Staurosira construens var. venter 11 15 .069

Staurosira elliptica 4 4 .021

Staurosirella leptostauron var. dubia 2 0 .005

Staurosirella pinnata 8 59 .178

Stephanodiscus niagarae 1 0 .003

Synedra rumpens var. familaris 0 1 .003

Synedra (GV) 0 1 .003

Tabellaria (central area) 0 1 .003

Unknown (raphid) 1 5 .016

Unknown 0 6 .016

TOTAL 175.5 201.5 1.000

3

Chrysophyte cysts 2 2

Scenedesmus coenobia 0 2

Sponge spicules 2 0
88 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 48–49 cm

Achnanthes exiguum 0 1 0.003

Achnanthes minutissima + vars. 23 13 .108

Aulacoseira ambigua 6 4 .030

Aulacoseira subarctica 0 2 .006

Aulacoseira (VV) 1 1 .006

Brachysira vitrea 2 3 .015

Cocconeis placentula var. eugypta 0 1 .003

Cocconeis placentula var. lineata 3 1 .012

Cyclotella stelligera 1 1 .006

Cymbella angustata 3 0 .009

Cymbella cistula 0 2 .006

Cymbella sp. 2 0 .006

Encyonema silesiacum 1 0 .003

Eunotia incisa 2 0 .006

Eunotia pectinalis 1.5 0 .005

Fragilaria capucina 4 2 .018

Geissleria ignota var. palustris 1 0 .003

Gomphonema tenellum 1 3 .012

Gomphonema (GV) 2 2 .012

Gomphonema truncatum var. capitatum 2 0 .006

Navicula atomus var. permitis 8 6 .042

Navicula cryptotenella 1 1 .006

Navicula lanceolata 0 1 .003

Navicula pelliculosa 5 3 .024

Navicula pseudoventralis 3 6 .027

Navicula radiofallax 0 2 .006

Navicula schadei 3 2 .015

Navicula seminuloides 2 1 .009

Navicula tripunctata 0 2 .006

Navicula (GV) (short) 15 13 .084

Navicula sp. 1 3 .012

Nitzschia amphibia 0 1 .003

Nitzschia sp. 0 3 .009

Pinnularia sp. 1 2 .009

Planothidium lanceolata var. dubia 0 1 .003

Pseudostaurosira brevistrata + vars. 10 13 .069

Sellaphora pupula 1 0 .003

Sellaphora rectangularis 0 1 .003

Sellaphora vitabunda 0 1 .003

Staurosira construens 15 21 .108

Staurosira construens var. venter 24 19 .129

Staurosira elliptica 3 11 .042

Staurosirella leptostauron 2 2 .012

Staurosirella leptostauron var. dubia 0 3 .009

Staurosirella pinnata 5 12 .051

Synedra acus 0 2 .006

Synedra rumpens var. familaris 6 0 .018

Unknown (raphid) 0 1 .003

Unknown 1 2 .009

TOTAL 161.5 171 1.000

3

Chrysophyte cysts 3 1

Scenedesmus coenbia 1 0

Tetraedron coenbia 1 0

Zooplankton parts 1 0
Table A8 89

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 52–54 cm

Achnanthes minutissima + vars. 10 13 0.070

Asterionella formosa 0 1 .003

Aulacoseira ambigua 1 2 .009

Aulacoseira italica 2 0 .006

Brachysira vitrea 1 0 .003

Cyclotella glomerata 0 2 .006

Cyclotella michiganiana 1 0 .003

Cymbella angustata 1 0 .003

Epithemia sp. 4 0 .012

Epithemia turgida 1 0 .003

Eunotia sp. 2.5 1 .011

Fragilaria capucina + vars. 11 0 .033

Fragilaria crotonensis 0 4 .012

Fragilaria cf. oldenburgiana 1 0 .003

Fragilaria vaucheriae 1 0 .003

Geissleria ignota var. palustris 1 0 .003

Gomphonema acuminatum 0 2 .006

Gomphonema (GV) 4 2 .018

Gomphonema sp. 3 2 .015

Navicula atomus var. permitis 13 18 .094

Navicula minima 2 2 .012

Navicula muralis 2 0 .006

Navicula pelliculosa 5 1 .018

Navicula pseudoventralis 1 8 .027

Navicula schadei 1 0 .003

Navicula (GV) (short) 8 4 .037

Navicula sp. 3 7 .030

Nitzschia amphibia 0 1 .003

Nitzschia sp. 2 0 .006

Pseudostaurosira brevistrata + vars. 9 18 .082

Sellaphora rectangularis 0 1 .003

Staurosira construens 14 26 .122

Staurosira construens var. venter 38 17 .167

Staurosira elliptica 8 3 .033

Staurosirella leptostauron var. dubia 0 1 .003

Staurosirella pinnata 17 12 .088

Staurosirella pinnata var. intercedens 2 0 .006

Stephanodiscus niagarae 1 0 .003

Synedra rumpens var. familaris 0 1 .003

Synedra (GV) 0 2 .006

Tabellaria fenestrata 1 0 .003

Unknown 3 3 .018

Unknown (raphid) 0 .000

Total 174.5 154 1.000
90 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from

Musky Bay MB-1 and MB-3 cores and Northeastern Bay LCO-1 

core, Lac Courte Oreilles, October 1999–Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not 

determined in all counts, therefore the concentration value may be zero. 

Concentration was not determined for samples from MB-1A.] 

Taxa Number 1 Number 2 Proportion

MB-1A, 54–56 cm

Achnanthes exiguum 2 0 0.006

Achnanthes minutissima + vars. 1 16 .052

Amphipleura pellucida .5 0 .002

Aulacoseira ambigua 0 4 .012

Aulacoseira italica 1 1 .006

Brachysira vitrea 1 1 .006

Cocconeis placentula var. lineata 0 1 .003

Cocconeis placentula (RV) 0 1 .003

Cyclotella glomerata 0 1 .003

Cyclotella michiganiana 0 3 .009

Cyclotella sp. 2 0 .006

Cymbella angustata 3 1 .012

Cymbella cistula 2 0 .006

Cymbella sp. 1 0 .003

Encyonema silesiacum 0 1 .003

Epithemia turgida 0 1 .003

Eunotia incisa .5 .5 .003

Eunotia sp. 0 2.5 .008

Fragilaria capucina + vars. 4 .5 .014

Fragilaria crotonensis 0 6 .018

Fragilaria vaucheriae 2 0 .006

Geissleria ignota var. palustris 0 1 .003

Gomphonema tenellum 0 1 .003

Gomphonema sp. 3 0 .009

Navicula atomus var. permitis 15 9 .074

Navicula lanceolata 2 1 .009

Navicula minima 2 4 .018

Navicula pelliculosa 4 1 .015

Navicula pseudoventralis 9 12 .065

Navicula schadei 4 1 .015

Navicula tripunctata 0 2 .006

Navicula (GV) (short) 12 12 .074

Navicula sp. 6 2 .025

Neidium iridis 2 0 .006

Planothidium lanceolata 1 0 .003

Pseudostaurosira brevistrata + vars. 6 10 .049

Reimeria sinuata 0 1 .003

Staurosira construens 32 19 .157

Staurosira construens var. venter 19 18 .114

Staurosira elliptica 6 5 .034

Staurosirella leptostauron var. dubia 4 2 .018

Staurosirella pinnata 12 9 .065

Stephanodiscus niagarae 1 0 .003

Synedra rumpens var. familaris 5 1 .018

Synedra sp. 0 1 .003

Tabellaria (central area) 1 0 .003

Unknown (raphid) 1 0 .003

Unknown 4 2 .018

Total 171 154.5 1.000
Table A8 91

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Proportion Number/g dry 

sediment

MB-1B, 0–1 cm

Achnanthidium minutissima + vars. 7 83 3 0.025 9.75E+07

Achnanthidium exiguum 0 10 0 .001 6.50E+06

Amphora ovalis var. affinis 0 10 0 .001 6.50E+06

Amphipleura pellucida 0 00 1 .001 0.00E+00

Aulacoseira ambigua 3 10 0 .005 2.60E+07

Aulacoseira italica 1 00 0 .001 6.50E+06

Cocconeis placentula var. lineata 1 10 5 .008 1.30E+07

Cocconeis placentula (RV) 2 11 0 .005 1.95E+07

Cocconeis placentula 0 02 0 .002 0.00E+00

Cyclotella comensis 0 01 0 .001 0.00E+00

Cyclotella michiganiana 1 00 0 .001 6.50E+06

Cymbella angustata 1 10 1 .004 1.30E+07

Cymbella sp. 0 01 0 .001 0.00E+00

Encyonema silesiacum 1 01 0 .002 6.50E+06

Epithemia arcus 1 00 0 .001 6.50E+06

Epithemia sp. 3 23 0 .010 3.25E+07

Epithemia turgida 0 10 0 .001 6.50E+06

Eunotia incisa 2 10 0 .004 1.95E+07

Eunotia soleirolii 2 00 0 .002 1.30E+07

Fragilaria capucina + vars. 9 32 33 7 .098 2.66E+08

Fragilaria constricta 2 20 0 .005 2.60E+07

Fragilaria crotonensis 0 50 0 .006 3.25E+07

Fragilaria vaucheriae 0 21 0 .004 1.30E+07

Geissleria ignota var. palustris 2 21 0 .006 2.60E+07

Gomphonema consector 1 10 0 .002 1.30E+07

Gomphonema gracile 0 00 1 .001 0.00E+00

Gomphonema parvulum f. micropus 0 10 0 .001 6.50E+06

Gomphonema parvulum 0 10 0 .001 6.50E+06

Gomphonema tenellum 3 21 2 .010 3.25E+07

Gomphonema sp. 1 11 1 .005 1.30E+07

Navicula atomus var. permitis 2 51 4 .015 4.55E+07

Navicula lanceolata 1 01 3 .006 6.50E+06

Navicula minima 2 51 3 .013 4.55E+07

Navicula seminuloides 1 01 0 .002 6.50E+06

Navicula pseudoventralis 2 41 1 .010 3.90E+07

Navicula seminulum 3 00 0 .004 1.95E+07

Navicula (GV) (short) 0 30 2 .006 1.95E+07

Navicula sp. 1 43 0 .010 3.25E+07

Neidium sp. 0 10 0 .001 6.50E+06

Nitzschia amphibia 4 3 2 1.5 .013 4.55E+07

Nitzschia fonticola 1 00 1 .002 6.50E+06

Nitzschia palea 1 21 3 .008 1.95E+07

Nitzschia sp. 0 .5 0 0 .001 3.25E+06

Pseudostaurosira brevistrata + vars. 0 6 33 10 .059 3.90E+07

Reimeria sinuata 0 10 0 .001 6.50E+06

Sellaphora rectangularis 0 10 0 .001 6.50E+06

Staurosira construens 67 35 23 46 .207 6.63E+08

Staurosira construens var. binodis 18 7 0 4 .035 1.62E+08

Staurosira contruens var. subsalina 0 01 0 .001 0.00E+00

Staurosira construens var. venter 47 46 27 22 .172 6.04E+08

Staurosira elliptica 19 19 4 10 .063 2.47E+08

Staurosirella pinnata 28 28 19 28 .125 3.64E+08

Stephanodiscus niagarae 0 10 0 .001 6.50E+06

Stephanodiscus sp. 0 10 0 .001 6.50E+06

Synedra demerarae 3 00 0 .004 1.95E+07

Synedra rumpens 0 11 0 .002 6.50E+06

Synedra rumpens var. familaris 1 20 1 .005 1.95E+07

Synedra sp. 0 00 1 .001 0.00E+00

Rhopalodia gibba 1 10 0 .002 1.30E+07

Unknown (raphid) 6 00 0 .007 3.90E+07

Unknown 1 00 0 .001 6.50E+06

TOTAL 252 243.5 168 161.5 1.000 3.22E+09

Chrysophyte cysts 0 0 2 2 0.00E+00

Scenedesmus coenobia 2 2 0 4 2.60E+07

Tetraedron coenobia 1 0 0 1 6.50E+06
92 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Number 5 Proportion Number/g dry 

sediment

MB-1B, 5–6 cm

Achnanthidium exiguum 1 00 00 0.001 1.06E+07

Achnanthidium lanceolata var. dubia 0 00 10 .001 0.00E+00

Achnanthidium minutissima + vars. 3 22 02 .011 5.28E+07

Amphora ovalis var. affinis 0 00 10 .001 0.00E+00

Amphora perpusilla 2 00 00 .002 2.11E+07

Amphora normanii 0 00 10 .001 0.00E+00

Aulacoseira ambigua 0 03 11 .006 0.00E+00

Aulacoseira (VV) 2 01 00 .004 2.11E+07

Cocconeis placentula var. eugypta 4 00 00 .005 4.23E+07

Cocconeis placentula var. lineata 0 04 21 .009 0.00E+00

Cocconeis placentula (RV) 2 00 11 .005 2.11E+07

Cyclotella sp. 0 30 00 .004 3.17E+07

Cymbella angustata 0 01 00 .001 0.00E+00

Cymbella cistula 1 01 00 .002 1.06E+07

Cymbella sp. 0 01 21 .005 0.00E+00

Encyonema silesiacum 0 10 02 .004 1.06E+07

Epithemia arcus 0 00 20 .002 0.00E+00

Epithemia turgida 0 32 02 .009 3.17E+07

Epithemia sp. 0 10 03 .005 1.06E+07

Eunotia incisa 0 0 2 2 .5 .006 0.00E+00

Eunotia pectinalis var. recta 0 00 10 .001 0.00E+00

Fragilaria capucina + vars. 47 4 17 4 15 .107 5.39E+08

Fragilaria crotonensis 3 11 00 .006 4.23E+07

Geissleria ignota var. palustris 1 00 00 .001 1.06E+07

Gomphonema angustatum 2 00 00 .002 2.11E+07

Gomphonema parvulum 1 01 00 .002 1.06E+07

Gomphonema tenellum 1 12 01 .006 2.11E+07

Gomphonema (GV) 0 20 02 .005 2.11E+07

Hantzschia amphioxys 0 0 0 0 .5 .001 0.00E+00

Navicula atomus var. permitis 2 04 03 .011 2.11E+07

Navicula glomus 1 00 00 .001 1.06E+07

Navicula lanceolata 2 01 01 .005 2.11E+07

Navicula minima 1 00 01 .002 1.06E+07

Navicula pseudoventralis 2 00 00 .002 2.11E+07

Navicula seminuloides 1 01 00 .002 1.06E+07

Navicula tripunctata 1 00 00 .001 1.06E+07

Navicula (GV) (short) 2 20 42 .012 4.23E+07

Navicula sp. 2 11 01 .006 3.17E+07

Nitzschia amphibia 1 13 20 .009 2.11E+07

Nitzschia palea 1 00 00 .001 1.06E+07

Nitzschia sp. 0 01 00 .001 0.00E+00

Pinnularia cuneicephala 0 00 01 .001 0.00E+00

Pseudostaurosira brevistrata + vars 33 17 27 10 6 .113 5.28E+08

Rhoicosphenia curvata 0 02 00 .002 0.00E+00

Staurosira construens 31 38 28 40 48 .228 7.29E+08

Staurosira construens var. binodis 4 0 1 16 0 .026 4.23E+07

Staurosira construens var. venter 30 21 17 28 40 .167 5.39E+08

Staurosira elliptica 4 8 8 10 7 .046 1.27E+08

Staurosirella pinnata 17 15 25 28 16 .124 3.38E+08

Staurosirella pinnata var. intercedens 0 00 01 .001 0.00E+00

Synedra rumpens var. familaris 0 00 20 .002 0.00E+00

Synedra ulna 2 00 00 .002 2.11E+07

Synedra sp. 0 01 00 .001 0.00E+00

Unknown (raphid) 0 11 01 .004 1.06E+07

Unknown 0 11 01 .004 1.06E+07

TOTAL 207 123 164 158 161 1.000 3.49E+09

Chrysophyte cysts 0 01 02 0

Scenedesmus coenobia 2 22 22 4.23E+07

Tetraedron coenobia 1 00 00 1.06E+07
Table A8 93

MB-1B, 10–11 cm

Achnanthidium lanceolata 0 01 00 0.001 1.79E+07

Achnanthidium lanceolata var. dubia 0 02 00 .002 3.59E+07

Achnanthidium lewisiana 0 00 10 .001 0.00E+00

Achnanthidium minutissima + vars. 1 15 11 .010 1.26E+08

Amphora perpusilla 0 00 01 .001 0.00E+00

Aulacoseira ambigua 0 10 00 .001 1.79E+07

Brachysira sp. 0 00 01 .001 0.00E+00

Cocconeis placentula var. lineata 1 21 02 .007 7.18E+07

Cocconeis placentula (RV) 1 21 20 .007 7.18E+07

Craticula cuspidata 0 00 01 .001 0.00E+00

Cyclotella michiganiana 0 00 11 .002 0.00E+00

Cyclotella sp. 0 04 00 .005 7.18E+07

Cymbella angustata 0 01 00 .001 1.79E+07

Cymbella cistula 0 00 30 .003 0.00E+00

Cymbella cymbiformis var. nonpunctata 1 00 00 .001 1.79E+07

Cymbella sp. 0 10 01 .002 1.79E+07

Epithemia arcus 0 00 10 .001 0.00E+00

Epithemia sp. 0 11 20 .005 3.59E+07

Eunotia flexuosa 0 .5 0 0 0 .001 8.97E+06

Fragilaria capucina + vars. 23 12 11 7 21 .084 8.25E+08

Fragilaria crotonensis 0 04 00 .005 7.18E+07

Geissleria ignota var. palustris 0 00 10 .001 0.00E+00

Gomphonema angustatum 0 00 20 .002 0.00E+00

Gomphonema consector 0 01 00 .001 1.79E+07

Gomphonema subclavatum var. commutatum 0 00 10 .001 0.00E+00

Gomphonema tenellum 1 03 10 .006 7.18E+07

Gomphonema sp. 1 02 11 .006 5.38E+07

Navicula atomus var. permitis 7 22 65 .025 1.97E+08

Navicula cryptotenella 1 00 10 .002 1.79E+07

Navicula glomus 0 20 00 .002 3.59E+07

Navicula lanceolata 1 11 01 .005 5.38E+07

Navicula minima 3 06 12 .014 1.61E+08

Navicula pseudoventralis 2 44 02 .014 1.79E+08

Navicula tripunctata 1 21 00 .005 7.18E+07

Navicula (short) (GV) 2 61 00 .010 1.61E+08

Navicula sp. 0 10 24 .008 1.79E+07

Nitzschia amphibia 1 2 2 0 1.5 .007 8.97E+07

Nitzschia palea 0 01 00 .001 1.79E+07

Nitzschia sp. 2.5 1 0 0 0 .004 6.28E+07

Pinnularia sp. 1 10 00 .002 3.59E+07

Pseudostaurosira brevistrata + vars. 26 45 10 9 2 .105 1.45E+09

Sellaphora pupula 0 00 01 .001 0.00E+00

Sellaphora bacillum 0 10 00 .001 1.79E+07

Staurosira construens 59 68 33 52 38 .285 2.87E+09

Staurosira construens var. binodis 3 51 66 .024 1.61E+08

Staurosira construens var. venter 20 45 34 27 35 .183 1.78E+09

Staurosira elliptica 1 3 5 11 17 .042 1.61E+08

Staurosirella pinnata 14 17 11 13 19 .084 7.53E+08

Staurosira pinnata var. lancettula 0 00 10 .001 0.00E+00

Stephanodiscus minutulus 1 00 00 .001 1.79E+07

Synedra minuscula 1 00 00 .001 1.79E+07

Synedra rumpens 0 02 00 .002 3.59E+07

Synedra rumpens var. familaris 1 00 00 .001 1.79E+07

Synedra sp. 0 00 01 .001 0.00E+00

Tabellaria sp. 0 0.5 0 0 0 .001 8.97E+06

Unknown (raphid) 2 11 00 .005 7.18E+07

Unknown 1 00 10 .002 1.79E+07

TOTAL 179.5 228 152 154 164.5 1.000 1.00E+10

Chrysophyte cysts 0 3 0 0 0 5.38E+07

Scenedesmus coenobia 7 1 2 10 5 4.48E+08

Sponge spicule 1 1 0 0 0 3.59E+07

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Number 5 Proportion Number/g dry 

sediment
94 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Proportion

Number/g 

dry 

sediment

MB-1B, 11–12 cm

Achnanthidium minutissima + vars. 0 3 4 7 0.019 6.62E+07

Aulacoseira ambigua 0 0 0 1 .001 0.00E+00

Cocconeis placentula 1 2 0 0 .004 4.73E+07

Cocconeis placentula var. lineata 2 1 2 0 .007 2.84E+07

Cocconeis placentula (RV) 2 0 0 0 .003 6.38E+06

Craticula cuspidata 0 0 1 0 .001 0.00E+00

Cyclotella ocellata 0 1 0 0 .001 2.21E+07

Cymbella angustata 0 2 0 1 .004 4.41E+07

Cymbella cistula 1 0 0 1 .003 3.19E+06

Cymbella sp. 1 0 0 1 .003 3.19E+06

Encyonema silesiacum 0 0 0 2 .003 0.00E+00

Epithemia arcus 0 0 0 1 .001 0.00E+00

Epithemia turgida 3 0 0 1 .005 9.57E+06

Epithemia sp. 0 1.5 0 1 .003 3.31E+07

Fragilaria capucina + vars. 12 4 13 12 .054 1.27E+08

Fragilaria crotonensis 2 0 0 0 .003 6.38E+06

Fragilaria radians 1 0 0 0 .001 3.19E+06

Gomphonema tenellum 1 1 0 3 .007 2.53E+07

Gomphonema truncatum 1 0 0 0 .001 3.19E+06

Gomphonema (GV) 3 0 0 0 .004 9.57E+06

Gomphonema sp. 0 1 0 1 .003 2.21E+07

Navicula lanceolata 1 1 2 0 .005 2.53E+07

Navicula minima 0 3 0 2 .007 6.62E+07

Navicula atomus var. permitis 3 2 2 3 .013 5.37E+07

Navicula pseudoventralis 1 3 2 3 .012 6.94E+07

Navicula glomus 0 2 0 1 .004 4.41E+07

Navicula seminuloides 0 4 3 0 .009 8.82E+07

Navicula (GV) (short) 2 0 0 0 .003 6.38E+06

Navicula sp. 2 0 0 3 .007 6.38E+06

Nitzschia amphibia 3 2 1 2.5 .011 5.37E+07

Nitzschia palea 0 0 0 .5 .001 0.00E+00

Nitzschia sp. 0 .5 0 2.5 .004 1.10E+07

Pseudostaurosira brevistrata + vars. 10 27 41 26 .138 6.28E+08

Sellaphora pupula 0 0 0 1 .001 0.00E+00

Sellaphora rectangularis 0 1 0 0 .001 2.21E+07

Staurosira construens 41 28 64 46 .237 7.49E+08

Staurosira construens var. binodis 6 16 2 8 .042 3.72E+08

Staurosira construens var. venter 22 10 27 51 .146 2.91E+08

Staurosira elliptica 7 16 16 11 .066 3.75E+08

Staurosirella pinnata 28 24 28 27 .142 6.19E+08

Stephanodiscus niagarae 0 0 0 1 .001 0.00E+00

Synedra amphicephala var. austriaca 0 1 0 0 .001 2.21E+07

Synedra rumpens 0 0 1 0 .001 0.00E+00

Synedra rumpens var. familaris 4 3 1 1 .012 7.89E+07

Unknown (raphid) 2 1 0 1 .005 2.84E+07

TOTAL 162 161 210 222.5 1.000 4.07E+09

Scenedesmus coenbia 5 5 1 1 2.21E+08

Tetraedron coenbia 0 0 1 0 0.00E+00

Sponge spicule 0 1 0 1 2.21E+07
Table A8 95

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Proportion Number/g dry 

sediment

MB-1B, 15–16 cm

Achnanthidium exiguum 0 1 0 0.002 1.29E+07

Achnanthidium lanceolata 0 1 0 .002 1.29E+07

Achnanthidium (GV) 0 2 0 .004 2.58E+07

Achnanthidium minutissima + vars. 0 7 1 .017 9.03E+07

Amphora ovalis var. affinis 0 0 1 .002 0.00E+00

Aulacoseira ambigua 1 0 0 .002 1.29E+07

Cocconeis placentula var. lineata 1 1 3 .010 2.58E+07

Cocconeis placentula (RV) 1 2 1 .008 3.87E+07

Cyclostephanos sp. 1 0 0 .002 1.29E+07

Cyclotella sp. 0 0 2 .004 0.00E+00

Cymbella angustata 0 0 1 .002 0.00E+00

Cymbella cistula 0 1 0 .002 1.29E+07

Cymbella tumida 0 1 0 .002 1.29E+07

Cymbella sp. 0 2 0 .004 2.58E+07

Epithemia turgida 4 0 0 .008 5.16E+07

Epithemia sp. 0 1 0 .002 1.29E+07

Eunotia flexuosa 0 .5 0 .001 6.45E+06

Fragilaria capucina + vars. 1 13 3 .036 1.81E+08

Fragilaria crotonensis 2 3 0 .010 6.45E+07

Fragilaria (GV) short no central area 0 0 7 .015 0.00E+00

Gomphonema acuminatum 0 1 0 .002 1.29E+07

Gomphonema affine 0 2 0 .004 2.58E+07

Gomphonema affine var insigne 0 1 0 .002 1.29E+07

Gomphonema sphaerophorum 0 0 2 .004 0.00E+00

Gomphonema subtile var. sagitta 1 0 0 .002 1.29E+07

Gomphonema tenellum 0 1 0 .002 1.29E+07

Gomphonema sp. 0 3 0 .006 3.87E+07

Navicula atomus var. permitis 1 6 0 .015 9.03E+07

Navicula glomus 0 1 0 .002 1.29E+07

Navicula minima 0 5 1 .013 6.45E+07

Navicula pseudoventralis 0 1 0 .002 1.29E+07

Navicula radiosafallax 0 1 4 .010 1.29E+07

Navicula tripunctata 0 1 0 .002 1.29E+07

Navicula (GV) 0 8 0 .017 1.03E+08

Navicula sp. 0 8 0 .017 1.03E+08

Nitzschia amphibia 2 4.5 2 .018 8.38E+07

Nitzschia dissipata 0 1 0 .002 1.29E+07

Nitzschia sp. .5 0 0 .001 6.45E+06

Pinnularia sp. 1 0 0 .002 1.29E+07

Pseudostaurosira brevistrata + vars. 2 7 8 .036 1.16E+08

Rhopalodia gibba 1 0 0 .002 1.29E+07

Sellaphora rectangularis 0 1 0 .002 1.29E+07

Staurosira construens 9 44 53 .222 6.84E+08

Staurosira construens var. binodis 0 3 24 .057 3.87E+07

Staurosira construens var. venter 39 63 12 .239 1.32E+09

Staurosira elliptica 0 14 1 .031 1.81E+08

Staurosirella pinnata 12 45 11 .143 7.35E+08

Staurosirella pinnata var. intercedens 0 2 0 .004 2.58E+07

Synedra acus 0 1 0 .002 1.29E+07

Synedra rumpens var. familaris 0 1 0 .002 1.29E+07

Unknown (raphid) 2 0 3 .010 2.58E+07

Unknown 1 1 1 .006 2.58E+07

TOTAL 82.5 260 134 1 4.42E+09

Chrysophyte scales 0 0 0.00E+00

Chrysophyte cysts 0 1 1.29E+07

Scenedesmus coenobia 0 0 1 1.29E+07

Sponge spicule 0 1 0 1.29E+07
96 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Proportion Number/g dry 

sediment

MB-1B, 20–21 cm

Achnanthidium minutissima + vars. 4 3 3 0.020 3.42E+07

Amphora coffeiformis 1 0 0 .002 4.88E+06

Asterionella formosa 1 0 0 .002 4.88E+06

Aulacoseira ambigua 3 1 0 .008 1.95E+07

Aulacoseira VV 0 0 1 .002 0.00E+00

Cocconeis placentula 0 1 0 .002 4.88E+06

Cocconeis placentula var. lineata 3 1 2 .012 1.95E+07

Cocconeis placentula (RV) 2 1 0 .006 1.47E+07

Cyclostephanos sp. 2 0 0 .004 9.77E+06

Cyclotella bodanica var. lemanica 1 0 0 .002 4.88E+06

Cymbella angustata 1 0 1 .004 4.88E+06

Cymbella cuspidata 0 1 0 .002 4.88E+06

Cymbella norvegica 0 1 0 .002 4.88E+06

Cymbella sp. 1 2 0 .006 1.47E+07

Encyonema silesiacum 1 0 0 .002 4.88E+06

Epithemia turgida 1 0 0 .002 4.88E+06

Eunotia incisa 0 0 1 .002 0.00E+00

Eunotia sp. .5 0 0 .001 2.44E+06

Fragilaria capucina + vars. 4 1 2 .014 2.44E+07

Fragilaria crotonensis 3 0 0 .006 1.47E+07

Geissleria ignota var. palustris 2 0 0 .004 9.77E+06

Gomphonema acuminatum 1 0 0 .002 4.88E+06

Gomphonema affine var. insigne 0 4 0 .008 1.95E+07

Gomphonema parvulum 0 0 1 .002 0.00E+00

Gomphonema tenellum 1 0 2 .006 4.88E+06

Gomphonema (GV) 1 2 0 .006 1.47E+07

Gomphonema sp. 3 0 0 .006 1.47E+07

Navicula lanceolata 3 0 2 .010 1.47E+07

Navicula minima 7 3 0 .020 4.88E+07

Navicula atomus var. permitis 4 4 2 .020 3.91E+07

Navicula pelliculosa 2 5 0 .014 3.42E+07

Navicula pseudoventralis 6 0 1 .014 2.93E+07

Navicula glomus 0 2 1 .006 9.77E+06

Navicula seminuloides 1 0 0 .002 4.88E+06

Navicula tripunctata 3 0 0 .006 1.47E+07

Navicula radiosa var. parva 1 0 0 .002 4.88E+06

Navicula radiosa var. tenella 0 1 0 .002 4.88E+06

Navicula variostriata 1 0 0 .002 4.88E+06

Navicula vitabunda 0 1 0 .002 4.88E+06

Navicula (GV) (short) 4 6 0 .020 4.88E+07

Navicula sp. 2 2 1 .010 1.95E+07

Nitzschia amphibia .5 4.5 4 .018 2.44E+07

Nitzschia palea 2 0 1 .006 9.77E+06

Nitzschia sp. 0 .5 0 .001 2.44E+06

Pinnularia sp. 0 1 0 .002 4.88E+06

Planothidium lanceolata 1 0 2 .006 4.88E+06

Pseudostaurosira brevistrata + vars. 10 15 8 .065 1.22E+08

Stauroneis sp. 0 1 0 .002 4.88E+06

Staurosira construens 45 14 30 .175 2.88E+08

Staurosira construens var. binodis 5 12 1 .035 8.30E+07

Staurosira construens var. venter 54 36 17 .210 4.40E+08

Staurosira elliptica 9 2 2 .026 5.37E+07

Staurosirella pinnata 40 27 19 .169 3.27E+08

Staurosirella pinnata var. lancettula 0 1 0 .002 4.88E+06

Stephanodiscus hantzschii 4 0 0 .008 1.95E+07

Stephanodiscus medius 1 0 0 .002 4.88E+06

Stephanodiscus minutulus 1 0 0 .002 4.88E+06

Stephanodiscus sp. 1 0 0 .002 4.88E+06

Synedra acus 0 1 0 .002 4.88E+06

Synedra rumpens var. familaris 0 1 1 .004 4.88E+06

Synedra (GV) 1 0 0 .002 4.88E+06

Synedra sp. 1 0 0 .002 4.88E+06

Unknown (raphid) 7 1 0 .016 3.91E+07

TOTAL 246 158 105 1.000 1.97E+09

Chrysophyte cysts 2 1 1 1.95E+07

Scenedesmus coenobia 5 1 0 2.93E+07
Table A8 97

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Proportion Number/g dry 

sediment

MB-1B, 30–31 cm

Achnanthidium minutissima + vars. 2 2 3 0.013 1.19E+08

Aulacoseira ambigua 3 1 1 .010 8.51E+07

Cocconeis placentula var. lineata 0 1 1 .004 3.41E+07

Cocconeis placentula (RV) 1 1 0 .004 3.41E+07

Cyclotella bodanica var. lemanica 1 0 0 .002 1.70E+07

Cyclotella glomerata 0 1 0 .002 1.70E+07

Cymbella cistula 0 0 1 .002 1.70E+07

Cymbella sp. 0 2 1 .006 5.11E+07

Encyonema silesiacum 0 2 0 .004 3.41E+07

Epithemia sorex 1 0 1 .004 3.41E+07

Eunotia incisa 2 0 1 .006 5.11E+07

Eunotia sp. 0 0 .5 .001 8.51E+06

Fragilaria capucina + vars. 3 4 1 .015 1.36E+08

Gomphonema angustatum 0 0 1 .002 1.70E+07

Gomphonema subtile 0 1 0 .002 1.70E+07

Gomphonema truncatum 0 0 1 .002 1.70E+07

Gomphonema sp. 1 2 2 .010 8.51E+07

Navicula atomus var. permitis 1 9 10 .038 3.41E+08

Navicula glomus 2 1 2 .010 8.51E+07

Navicula lanceolata 0 0 3 .006 5.11E+07

Navicula minima 1 0 1 .004 3.41E+07

Navicula pelliculosa 4 3 8 .029 2.55E+08

Navicula pseudoventralis 3 0 1 .008 6.81E+07

Navicula radiosafallax 1 0 0 .002 1.70E+07

Navicula seminuloides 3 0 0 .006 5.11E+07

Navicula (GV) (short) 3 4 15 .042 3.75E+08

Navicula sp. 0 1 3 .008 6.81E+07

Neidium iridis 0 0 1 .002 1.70E+07

Nitzschia amphibia 0 0 5 .010 8.51E+07

Nitzschia palea 0 1 0 .002 1.70E+07

Nitzschia sp. 0 0 1 .002 1.70E+07

Pseudostaurosira brevistrata + vars. 4 10 20 .065 5.79E+08

Sellaphora rectangularis 2 0 0 .004 3.41E+07

Staurosira construens 39 16 68 .236 2.09E+09

Staurosira construens var. binodis 28 1 2 .060 5.28E+08

Staurosira construens var. venter 30 14 36 .154 1.36E+09

Staurosira elliptica 7 15 19 .079 6.98E+08

Staurosirella leptostauron var. dubia 0 0 5 .010 8.51E+07

Staurosirella pinnata 30 7 30 .129 1.14E+09

Synedra demerarae 0 0 1 .002 1.70E+07

Synedra rumpens var. familaris 0 0 1 .002 1.70E+07

Synedra sp. 0 0 3 .006 5.11E+07

Unknown (raphid) 0 0 0 .000 0.00E+00

Unknown 0 0 0 .000 0.00E+00

TOTAL 172 99 249.5 1.000 8.86E+09

Chrysophyte cysts 0 0 1 1.70E+07

Scenedesmus coenobia 2 2 5 1.19E+08

Cosmarium coenobia 0 0 1 1.70E+07

Sponge spicule 0 1 2 3.41E+07
98 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Number 5 Proportion Number/g dry 

sediment

MB-1B, 40–41 cm

Achnanthidium exigua 0 0 0 2 0 0.004 0.00E+00

Achnanthidium minutissima + vars. 4 3 2 7 4 .036 1.67E+07

Asterionella formosa 1 0 0 0 0 .002 2.39E+06

Aulacoseira ambigua 3 0 4 0 0 .013 7.17E+06

Aulacoseira italica 0 0 3 0 0 .005 0.00E+00

Brachysira vitrea 1 0 0 0 0 .002 2.39E+06

Cocconeis placentula var. eugypta 1 0 0 2 0 .005 2.39E+06

Cocconeis placentula var. lineata 1 1 3 0 1 .011 4.78E+06

Cocconeis placentula (RV) 0 0 1 1 1 .005 0.00E+00

Cocconeis placentula 0 0 0 1 2 .005 0.00E+00

Cyclostephanos sp. 0 1 0 1 0 .004 2.39E+06

Caloneis ventricosa var. truncatula 0 0 0 0 2 .004 0.00E+00

Cyclotella delicatula 0 0 0 1 0 .002 0.00E+00

Cyclotella michiganiana 0 0 0 0 1 .002 0.00E+00

Cyclotella sp. 0 1 0 1 0 .004 2.39E+06

Cymbella angustata 0 0 1 0 0 .002 0.00E+00

Cymbella cistula 0 0 0 1 1 .004 0.00E+00

Cymbella hybrida var. lanceolata 2 0 0 0 0 .004 4.78E+06

Cymbella sp. 0 0 0 0 1 .002 0.00E+00

Epithemia arcus 0 0 1 0 0 .002 0.00E+00

Epithemia turgida 3 1 0 0 0 .007 9.56E+06

Epithemia sp. 0 0 0 1 0 .002 0.00E+00

Eunotia flexuosa 0 0 1 0 0 .002 0.00E+00

Eunotia incisa 1 0 0 0 0 .002 2.39E+06

Eunotia pectinalis var. recta 0 0 0 .5 0 .001 0.00E+00

Fragilaria capucina + vars. 2 7 6 10 3 .050 2.15E+07

Fragilaria crotonensis 0 1 1 8 0 .018 2.39E+06

Fragilaria vaucheriae 0 1 0 1 0 .004 2.39E+06

Gomphonema affine 0 1 0 1 0 .004 2.39E+06

Gomphonema sp. 1 0 0 0 0 .002 2.39E+06

Navicula atomus var. permitis 1 4 2 8 6 .038 1.20E+07

Navicula glomus 3 0 1 2 0 .011 7.17E+06

Navicula lanceolata 0 0 3 0 1 .007 0.00E+00

Navicula minima 2 0 0 3 1 .011 4.78E+06

Navicula perparva 1 0 0 0 0 .002 2.39E+06

Navicula pseudoventralis 3 2 0 5 1 .020 1.20E+07

Navicula seminuloides 1 0 1 2 0 .007 2.39E+06

Navicula (GV) (short) 4 4 2 2 6 .032 1.91E+07

Navicula sp. 1 3 0 4 4 .021 9.56E+06

Neidium iridis 0 0 1 0 0 .002 0.00E+00

Nitzschia adapta 0 .5 0 .5 0 .002 1.20E+06

Nitzschia palea 0 0 0 1 0 .002 0.00E+00

Nitzschia sp. 0 0 1 0 0 .002 0.00E+00

Pinnularia sp. 0 0 0 0 1 .002 0.00E+00

Planothidium lanceolata 1 0 0 0 0 .002 2.39E+06

Pseudostaurosira brevistrata + vars. 0 2 3 9 21 .063 4.78E+06

Rhopalodia gibba 0 0 0 .5 0 .001 0.00E+00

Sellaphora rectangularis 0 1 0 0 0 .002 2.39E+06

Stauroneis sp. 0 0 0 0 1 .002 0.00E+00

Staurosira construens 26 8 12 21 59 .225 8.13E+07

Staurosira construens var. binodis 1 0 0 7 0 .014 2.39E+06

Staurosira contruens var. subsalina 0 0 1 0 0 .002 0.00E+00

Staurosira construens var. venter 11 3 18 24 19 .134 3.35E+07

Staurosira elliptica 0 3 1 6 1 .020 7.17E+06

Staurosirella pinnata 11 15 9 15 14 .114 6.22E+07

Staurosirella pinnata var. lancettula 0 0 0 1 0 .002 0.00E+00

Stephanodiscus hantzschii 0 0 0 3 2 .009 0.00E+00

Stephanodiscus niagarae 0 0 0 2 0 .004 0.00E+00

Stephanodiscus parvus 0 0 0 2 0 .004 0.00E+00

Stephanodiscus sp. 0 0 0 6 0 .011 0.00E+00

Synedra acus 0 0 0 1 0 .002 0.00E+00

Synedra demerarae 1 0 0 0 0 .002 2.39E+06

Synedra rumpens var. familaris 0 0 0 2 0 .004 0.00E+00

Synedra ulna 1 0 0 0 0 .002 2.39E+06

Synedra sp. 1 0 0 2 0 .005 2.39E+06

Tabellaria flocculosa str. IIIp 0 0 0 1 0 .002 0.00E+00

Unknown (raphid) 1 0 0 1 1 .005 2.39E+06

Unknown 2 1 2 0 0 .009 7.17E+06

TOTAL 92 63.5 80 169.5 154 1.000 3.72E+08

Chrysophyte cysts 2 0 0 0 0 4.78E+06

Scenedesmus coenobia 4 1 3 1 0 1.20E+07

Tetraedron coenobia 0 0 0 0 2 0.00E+00

Sponge spicule 0 1 0 0 0 2.39E+06
Table A8 99

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 45–46 cm

Achnanthidium lewisiana 1 0 0.002 6.53E+06

Achnanthidium minutissima + vars. 25 13 .074 2.48E+08

Aulacoseira ambigua 2 0 .004 1.31E+07

Aulacoseira italica 0 2 .004 1.31E+07

Aulacoseira subarctica 0 2 .004 1.31E+07

Aulacoseira (VV) 1 0 .002 6.53E+06

Aulacoseira sp. 0 1 .002 6.53E+06

Cocconeis neothumensis 0 1 .002 6.53E+06

Cocconeis placentula 2 0 .004 1.31E+07

Cocconeis placentula var. lineata 2 4 .012 3.92E+07

Cocconeis placentula (RV) 4 2 .012 3.92E+07

Cyclotella glomerata 0 1 .002 6.53E+06

Cyclotella michiganiana 0 1 .002 6.53E+06

Cyclotella ocellata 1 0 .002 6.53E+06

Cymbella angustata 2 1 .006 1.96E+07

Cymbella cuspidata 1 0 .002 6.53E+06

Cymbella hybrida var. lanceolata 2 0 .004 1.31E+07

Cymbella subaequalis 1 0 .002 6.53E+06

Cymbella tumida 1 0 .002 6.53E+06

Cymbella sp. 2 0 .004 1.31E+07

Eunotia incisa 1 1 .004 1.31E+07

Eunotia sp. .5 0 .001 3.26E+06

Fragilaria capucina + vars. 5 13 .035 1.18E+08

Fragilaria crotonensis 8 0 .015 5.22E+07

Fragilaria oldenburgiana 2 0 .004 1.31E+07

Fragilaria radians 1 0 .002 6.53E+06

Fragilaria vaucheriae 2 3 .010 3.26E+07

Geissleria ignota var. palustris 1 0 .002 6.53E+06

Gomphonema subtile var. sagitta 1 0 .002 6.53E+06

Gomphonema tenellum 5 3 .015 5.22E+07

Gomphonema (GV) 2 0 .004 1.31E+07

Gomphonema sp. 1 0 .002 6.53E+06

Navicula atomus var. permitis 9 12 .041 1.37E+08

Navicula cryptotenella 2 1 .006 1.96E+07

Navicula glomus 3 0 .006 1.96E+07

Navicula lanceolata 3 0 .006 1.96E+07

Navicula minima 5 5 .019 6.53E+07

Navicula perparva 2 2 .008 2.61E+07

Navicula pseudoventralis 8 13 .041 1.37E+08

Navicula seminuloides 5 1 .012 3.92E+07

Navicula (GV) (short) 16 16 .062 2.09E+08

Navicula sp. 3 3 .012 3.92E+07

Neidium sp. 1 0 .002 6.53E+06

Nitzschia dissipata 1 0 .002 6.53E+06

Nitzschia palea 1 0 .002 6.53E+06

Nitzschia sp. .5 2 .005 1.63E+07

Pinnularia sp. 1 0 .002 6.53E+06

Pseudostaurosira brevistrata + vars. 3 13 .031 1.04E+08

Rhopalodia gibba .5 0 .001 3.26E+06

Rhopalodia gibba var. parallela 2 0 .004 1.31E+07

Sellaphora pupula 1 0 .002 6.53E+06

Sellaphora rectangularis 1 0 .002 6.53E+06

Stauroneis anceps f. gracilis 1 0 .002 6.53E+06

Stauroneis phoenicenteron f. gracilis 1 0 .002 6.53E+06

Staurosira construens 69 15 .163 5.48E+08

Staurosira construens var. venter 10 85 .184 6.20E+08

Staurosira elliptica 2 7 .017 5.88E+07

Staurosirella leptostauron var. dubia 2 2 .008 2.61E+07

Staurosirella pinnata 18 23 .079 2.68E+08

Stephanodiscus niagarae 0 1 .002 6.53E+06

Synedra acus 0 1 .002 6.53E+06

Synedra amphicephala var. austriaca 1 0 .002 6.53E+06

Synedra rumpens 1 0 .002 6.53E+06

Synedra rumpens var. familaris 2 2 .008 2.61E+07

Synedra (GV) 4 0 .008 2.61E+07

Synedra sp. 1 0 .002 6.53E+06

Tabellaria (central area) 0 1 .002 6.53E+06

Tabularia fasciculata 1 0 .002 6.53E+06

Unknown (raphid) 1 2 .006 1.96E+07

Unknown 3 0 .006 1.96E+07

TOTAL 261.5 255 1.000 3.37E+09

3

Chrysophyte scales 1 1 1.31E+07

Chrysophyte cysts 0 3 1.96E+07

Scenedesmus coenobia 7 2 5.88E+07

Tetraedron coenobia 0 1 6.53E+06
100 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and Northeastern Bay 

LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Number 5 Proportion Number/g dry 

sediment

MB-1B, 50–52 cm

Achnanthidium minutissima + vars. 9 9 28 11 18 0.100 7.59E+07

Amphora ovalis var. affinis 100 02 .004 4.22E+06

Amphora perpusilla 010 00 .001 4.22E+06

Amphipleura pellucida 0 0 .5 0 0 .001 0.00E+00

Asterionella formosa 001 00 .001 0.00E+00

Aulacoseira ambigua 001 09 .013 0.00E+00

Aulacoseira italica 100 04 .007 4.22E+06

Aulacoseira subarctica 002 00 .003 0.00E+00

Aulacoseira (VV) 000 12 .004 0.00E+00

Aulacoseira sp. 010 00 .001 4.22E+06

Brachysira vitrea 002 00 .003 0.00E+00

Cocconeis placentula 000 10 .001 0.00E+00

Cocconeis placentula var. eugypta 010 00 .001 4.22E+06

Cocconeis placentula var. lineata 000 42 .008 0.00E+00

Cocconeis placentula (RV) 111 00 .004 8.43E+06

Craticula cuspidata 100 00 .001 4.22E+06

Cyclotella bodanica var. lemanica 000 01 .001 0.00E+00

Cyclotella glomerata 101 00 .003 4.22E+06

Cyclotella michiganiana 000 02 .003 0.00E+00

Cyclotella ocellata 000 01 .001 0.00E+00

Cyclotella stelligera 000 11 .003 0.00E+00

Cymbella angustata 031 01 .007 1.26E+07

Cymbella cistula 000 01 .001 0.00E+00

Cymbella minuta 001 00 .001 0.00E+00

Cymbella sp. 010 01 .003 4.22E+06

Encyonema silesiacum 001 10 .003 0.00E+00

Epithemia sp. 000 01 .001 0.00E+00

Epithemia turgida 003 10 .005 0.00E+00

Eunotia incisa 0 .5 0 1 .5 .003 2.11E+06

Eunotia pectinalis 0 0 0 0 1.5 .002 0.00E+00

Eunotia soleirolii 002 00 .003 0.00E+00

Eunotia sp. 2 0 0 0 2.5 .006 8.43E+06

Fragilaria capucina + vars. 2 2 2 10 5 .028 1.69E+07

Fragilaria crotonensis 0 3 0 10 0 .017 1.26E+07

Fragilaria vaucheriae 000 12 .004 0.00E+00

Gomphonema affine var. insigne 000 10 .001 0.00E+00

Gomphonema tenellum 003 32 .011 0.00E+00

Gomphonema (GV) 030 02 .007 1.26E+07

Gomphonema sp. 111 00 .004 8.43E+06

Karayevia exigua 110 11 .005 8.43E+06

Navicula atomus var. permitis 5 13 12 20 26 .102 7.59E+07

Navicula explanata 010 00 .001 4.22E+06

Navicula glomus 142 29 .024 2.11E+07

Navicula lanceolata 000 31 .005 0.00E+00

Navicula minima 508 33 .025 2.11E+07

Navicula perparva 011 32 .009 4.22E+06

Navicula pseudoventralis 2 4 13 11 8 .051 2.53E+07

Navicula radiosa 000 10 .001 0.00E+00

Navicula radiosafallax 020 02 .005 8.43E+06

Navicula seminuloides 403 22 .015 1.69E+07

Navicula ventralis 100 00 .001 4.22E+06

Navicula (GV) (short) 4 5 16 17 21 .084 3.79E+07

Navicula sp. 014 22 .012 4.22E+06
Table A8 101

MB-1B, 50–52 cm—Continued

Nitzschia amphibia 220 01 .007 1.69E+07

Nitzschia adapta 010 00 .001 4.22E+06

Nitzschia palea 000 33 .008 0.00E+00

Nitzschia sp. 0 0 1 0 2.5 .005 0.00E+00

Pinnularia sp. 002 01 .004 0.00E+00

Planothidium lanceolata 000 02 .003 0.00E+00

Pseudostaurosira brevistrata + vars. 548 84 .039 3.79E+07

Rhopalodia gibba 0 0 0 .5 .5 .001 0.00E+00

Sellaphora pupula 000 10 .001 0.00E+00

Sellaphora rectangularis 000 22 .005 0.00E+00

Stauroneis sp. 000 10 .001 0.00E+00

Staurosira construens 14 6 4 6 12 .056 8.43E+07

Staurosira construens var. binodis 000 04 .005 0.00E+00

Staurosira construens var. venter 13 11 13 2 21 .080 1.01E+08

Staurosira elliptica 0 4 7 7 12 .040 1.69E+07

Staurosirella leptostauron var. dubia 002 21 .007 0.00E+00

Staurosirella pinnata 6 3 12 15 23 .079 3.79E+07

Stephanodiscus minutulus 000 10 .001 0.00E+00

Synedra acus 000 01 .001 0.00E+00

Synedra minuscula 000 21 .004 0.00E+00

Synedra rumpens var. familaris 131 14 .013 1.69E+07

Synedra (GV) 000 23 .007 0.00E+00

Synedra sp. 001 00 .001 0.00E+00

Tabellaria fenestrata 000 01 .001 0.00E+00

Unknown (raphid) 202 02 .008 8.43E+06

Unknown 100 30 .005 4.22E+06

TOTAL 86 92.5 162.5 167.5 239.5 1.000 7.53E+08

Chrysophyte cysts 030 00 1.26E+07

Scenedesmus coenobia 102 04 4.22E+06

Zooplankton parts 000 01 0.00E+00

Sponge spicule 010 21 4.22E+06

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and Northeastern Bay 

LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Number 5 Proportion Number/g dry 

sediment
102 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 

cores and Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Proportion Number/g dry 

sediment

MB-1B, 60–62 cm

Achnanthidium minutissima + vars. 19 7 23 0.095 1.46E+08

Asterionella formosa 1 0 0 .002 2.97E+06

Aulacoseira ambigua 5 0 11 .031 4.75E+07

Aulacoseira granulata 0 3 0 .006 8.91E+06

Aulacoseira italica 0 2 1 .006 8.91E+06

Aulacoseira (VV) 1 0 0 .002 2.97E+06

Brachysira vitrea 2 0 2 .008 1.19E+07

Cocconeis placentula var. lineata 1 0 0 .002 2.97E+06

Cyclotella glomerata 1 1 2 .008 1.19E+07

Cyclotella stelligera 3 0 0 .006 8.91E+06

Cyclotella sp. 0 0 1 .002 2.97E+06

Cymbella angustata 1 0 2 .006 8.91E+06

Cymbella cistula 0 0 4 .008 1.19E+07

Cymbella tumida 1 0 0 .006 8.91E+06

Cymbella sp. 0 0 4 .002 2.97E+06

Encyonema silesiacum 1 0 2 .008 1.19E+07

Eunotia incisa 2 0 0 .004 5.94E+06

Eunotia flexuosa 0 0 .5 .001 1.49E+06

Eunotia sp. 0 0 1.5 .003 4.46E+06

Fragilaria capucina + vars. 4 8 3 .029 4.46E+07

Fragilaria crotonensis 0 2 5 .014 2.08E+07

Fragilaria radians 0 0 1 .029 4.46E+07

Fragilaria vaucheriae 0 1 0 .002 2.97E+06

Geissleria ignota var. palustris 1 0 0 .002 2.97E+06

Gomphonema affine 1 0 0 .002 2.97E+06

Gomphonema subtile 0 1 1 .004 5.94E+06

Gomphonema tenellum 2 2 1 .010 1.49E+07

Gomphonema (GV) 3 6 3 .023 3.56E+07

Gomphonema sp. 3 1 1 .010 1.49E+07

Navicula atomus var. permitis 10 14 36 .116 1.78E+08

Navicula glomus 1 0 4 .010 1.49E+07

Navicula lanceolata 0 0 2 .004 5.94E+06

Navicula laterostrata 0 0 2 .004 5.94E+06

Navicula minima 7 2 6 .029 4.46E+07

Navicula pelliculosa 0 5 22 .052 8.02E+07

Navicula pseudoventralis 7 3 10 .039 5.94E+07

Navicula seminuloides 6 0 0 .012 1.78E+07

Navicula (GV) (short) 18 6 22 .089 1.37E+08

Navicula sp. 3 0 7 .019 2.97E+07

Neidium iridis 0 0 1 .002 2.97E+06

Nitzschia amphibia 0.5 2 0 .005 7.43E+06

Nitzschia sp. 0 1 6 .014 2.08E+07

Pinnularia sp. 1 0 0 .002 2.97E+06

Planothidium lanceolata 1 0 0 .002 2.97E+06

Pseudostaurosira brevistrata + vars. 12 0 10 .043 6.53E+07

Sellaphora rectangularis 0 2 0 .004 5.94E+06

Staurosira construens 8 6 14 .054 8.32E+07

Staurosira construens var. venter 11 4 10 .048 7.43E+07

Staurosira elliptica 1 2 5 .016 2.38E+07

Staurosirella leptostauron var. dubia 1 3 11 .029 1.07E+08

Staurosirella pinnata 26 6 4 .070 2.97E+06

Stephanodiscus medius 0 0 1 .004 5.94E+06

Synedra acus 0 1 1 .004 5.94E+06

Synedra minuscula 0 0 2 .002 2.97E+06

Synedra rumpens var. familaris 0 0 2 .004 5.94E+06

Synedra ulna 0 0 2 .004 5.94E+06

Synedra (GV) 0 0 1 .002 2.97E+06

Tabellaria (central area) 0 0 1 .002 2.97E+06

Unknown (raphid) 1 2 2 .010 1.49E+07

Unknown 3 0 0 .006 8.91E+06

TOTAL 169.5 93 253 1.000 1.53E+09

Chrysophyte cysts 1 0 5 1.78E+07

Scenedesmus coenobia 2 2 5 2.67E+07

Sponge spicule 0 0 1 2.97E+06
Table A8 103

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 62–64 cm

Achnanthidium exigua 1 0 0.002 5.27E+06

Achnanthidium minutissima + vars. 21 28 .090 2.58E+08

Asterionella formosa 1 0 .002 5.27E+06

Aulacoseira ambigua 4 4 .015 5.27E+07

Aulacoseira granulata 2 0 .004 1.05E+07

Aulacoseira (VV) 1 1 .004 0.00E+00

Aulacoseira sp. 1 0 .002 5.27E+06

Brachysira vitrea 3 2 .009 2.64E+07

Cocconeis placentula var. lineata 0 1 .002 1.05E+07

Cocconeis placentula (RV) 1 0 .002 0.00E+00

Craticula cuspidata 0 1 .002 5.27E+06

Cyclotella stelligera 0 1 .002 5.27E+06

Cymbella angustata 2 1 .006 1.58E+07

Cymbella minuta 1 0 .002 5.27E+06

Cymbella sp. 0 2 .004 1.05E+07

Epithemia arcus 1 0 .002 5.27E+06

Epithemia sp. 0 2 .004 1.05E+07

Eunotia incisa .5 2.5 .006 1.58E+07

Eunotia pectinalis 0 1.5 .003 7.91E+06

Eunotia sp. 0 .5 .001 2.64E+06

Fragilaria capucina + vars. 14 4 .033 9.49E+07

Fragilaria crotonensis 0 10 .018 5.27E+07

Fragilaria vaucheriae 2 2 .007 2.11E+07

Geissleria ignota var. palustris 2 1 .006 1.58E+07

Gomphonema subclavatum var. commutatum 2 0 .004 1.05E+07

Gomphonema tenellum 2 3 .009 2.64E+07

Gomphonema truncatum 0 2 .004 1.05E+07

Gomphonema (GV) 4 0 .007 2.11E+07

Gomphonema sp. 0 3 .006 1.58E+07

Navicula atomus var. permitis 32 24 .103 3.32E+08

Navicula cryptotenella 1 0 .002 5.27E+06

Navicula glomus 2 4 .011 3.16E+07

Navicula lanceolata 0 5 .009 2.64E+07

Navicula minima 8 10 .033 1.03E+08

Navicula muralis 0 2 .004 0.00E+00

Navicula pelliculosa 6 13 .035 1.09E+08

Navicula pseudoventralis 9 13 .041 1.26E+08

Navicula radiosafallax 1 0 .002 5.27E+06

Navicula seminuloides 2 1 .006 1.58E+07

Navicula tripunctata 2 0 .004 1.05E+07

Navicula (GV) (short) 4 6 .018 5.27E+07

Navicula sp. 9 4 .024 6.85E+07

Neidium sp. 0 1 .002 5.27E+06

Nitzschia palea 1 0 .002 5.27E+06

Nitzschia sp. 4.5 4 .016 4.48E+07

Planothidium lanceolata 2 0 .004 1.05E+07

Pseudostaurosira brevistrata + vars. 16 12 .052 1.48E+08

Sellaphora pupula 1 0 .002 5.27E+06

Sellaphora rectangularis 0 1 .002 5.27E+06

Stauroneis recondita 0 1 .002 5.27E+06

Stauroneis sp. 0 1 .002 5.27E+06

Staurosira construens 38 41 .146 4.17E+08

Staurosira construens var. venter 21 12 .061 1.74E+08

Staurosira elliptica 12 11 .042 1.21E+08

Staurosirella leptostauron var. dubia 0 4 .007 2.11E+07

Staurosirella pinnata 25 25 .092 2.64E+08

Staurosirella pinnata var. lancettula 2 2 .007 2.11E+07

Stephanodiscus minutulus 1 0 .002 5.27E+06

Stephanodiscus niagarae 1 0 .002 5.27E+06

Synedra acus 0 1 .002 5.27E+06

Synedra rumpens var. familaris 1 1 .004 1.05E+07

Synedra ulna 1 0 .002 5.27E+06

Tabellaria (central area) 1 0 .002 5.27E+06

Unknown (raphid) 2 0 .004 1.05E+07

TOTAL 271 271.5 1.000 2.91E+09

Chrysophyte cysts 1 1 1.05E+07

Scenedesmus coenobia 3 1 2.11E+07

Sponge spicule 0 1 5.27E+06
104 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 64–66 cm

Achnanthidium exiguum 2 0 0.004 1.39E+07

Achnanthidium minutissima + vars. 22 27 .094 3.40E+08

Achnanthidium sp. 0 1 .002 6.95E+06

Asterionella formosa 0 2 .004 1.39E+07

Aulacoseira ambigua 9 3 .023 8.33E+07

Aulacoseira subarctica 0 1 .002 6.95E+06

Aulacoseira sp. 1 1 .004 1.39E+07

Brachysira vitrea 1 1 .004 1.39E+07

Brachysira sp. 2 0 .004 1.39E+07

Cocconeis placentula var. lineata 4 1 .010 3.47E+07

Cocconeis placentula (RV) 0 1 .002 6.95E+06

Cyclotella glomerata 1 4 .010 3.47E+07

Cymbella angustata 2 1 .006 2.08E+07

Cymbella cistula 1 3 .008 2.78E+07

Cymbella cymbiformis 0 2 .004 1.39E+07

Cymbella naviculiformis 2 0 .004 1.39E+07

Cymbella sp. 1 2 .006 2.08E+07

Epithemia arcus 0 1 .002 6.95E+06

Eunotia incisa .5 1 .003 1.04E+07

Eunotia pectinalis 0 1 .002 6.95E+06

Eunotia sp. 0 6 .012 4.17E+07

Fragilaria capucina + vars. 4 6 .019 6.95E+07

Fragilaria crotonensis 5 9 .027 9.72E+07

Fragilaria vaucheriae 1 0 .002 6.95E+06

Geissleria ignota var. palustris 0 1 .002 6.95E+06

Gomphonema acuminatum 0 1 .002 6.95E+06

Gomphonema tenellum 0 1 .002 6.95E+06

Gomphonema (GV) 6 8 .027 9.72E+07

Gomphonema sp. 1 1 .004 1.39E+07

Navicula atomus var. permitis 19 12 .059 2.15E+08

Navicula cryptotenella 2 1 .006 2.08E+07

Navicula explanata 1 0 .002 6.95E+06

Navicula glomus 0 3 .006 2.08E+07

Navicula lanceolata 5 1 .012 4.17E+07

Navicula minima 8 7 .029 1.04E+08

Navicula perparva 2 3 .010 3.47E+07

Navicula pseudoventralis 8 13 .040 1.46E+08

Navicula seminuloides 0 1 .002 6.95E+06

Navicula tripunctata 6 0 .012 4.17E+07

Navicula (GV) (short) 1 4 .010 3.47E+07

Navicula sp. 6 11 .033 1.18E+08

Neidium sp. 0 1 .002 6.95E+06

Nitzschia palea .5 0 .001 3.47E+06

Nitzschia sp. 2 4 .012 4.17E+07

Pinnularia sp. 1 0 .002 6.95E+06

Planothidium lanceolata 1 0 .002 6.95E+06

Pseudostaurosira brevistrata + vars. 8 3 .021 7.64E+07

Rhopalodia gibba .5 0 .001 3.47E+06

Sellaphora rectangularis 0 2 .004 1.39E+07

Sellaphora seminulum 0 2 .004 1.39E+07

Staurosira construens 57 26 .159 5.77E+08

Staurosira construens var. binodis 7 0 .013 4.86E+07

Staurosira construens var. venter 32 26 .111 4.03E+08

Staurosira elliptica 20 6 .050 1.81E+08

Staurosirella pinnata 6 32 .073 2.64E+08

Staurosirella pinnata var. lancettula 2 0 .004 1.39E+07

Synedra rumpens var. familaris 2 0 .004 1.39E+07

Synedra (GV) 0 2 .004 1.39E+07

Synedra sp. 1 1 .004 1.39E+07

Tabellaria (central area) 0 1 .002 6.95E+06

Unknown (raphid) 2 2 .008 2.78E+07

Unknown 2 4 .012 4.17E+07

TOTAL 267.5 254 1.000 3.62E+09

Chrysophyte cysts 2 1 2.08E+07

Scenedesmus coenobia 5 2 4.86E+07
Table A8 105

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 66–68 cm

Achnanthidium exiguum 2 0 0.004 1.22E+07

Achnanthidium lewisiana 1 0 .002 6.11E+06

Achnanthidium minutissima + vars. 39 28 .123 4.09E+08

Aulacoseira ambigua 0 8 .015 4.89E+07

Caloneis ventricosa 0 2 .004 1.22E+07

Cocconeis placentula 1 2 .005 1.83E+07

Cyclotella glomerata 0 1 .002 6.11E+06

Cyclotella stelligera 2 1 .005 1.83E+07

Cyclotella sp. 3 1 .007 2.44E+07

Cymbella angustata 1 3 .007 2.44E+07

Cymbella cuspidata 1 0 .002 6.11E+06

Cymbella hebridica 0 1 .002 6.11E+06

Cymbella subaequalis 1 1 .004 1.22E+07

Cymbella sp. 2 1 .005 1.83E+07

Encyonema silesiacum 1 1 .004 1.22E+07

Epithemia turgida 1 0 .002 6.11E+06

Epithemia sp. 3 0 .005 1.83E+07

Eunotia praerupta 1 0 .002 6.11E+06

Eunotia sp. .5 0 .001 3.06E+06

Fragilaria capucina + vars. 1 1 .004 1.22E+07

Fragilaria crotonensis 0 2 .004 1.22E+07

Geissleria ignota var. palustris 3 1 .007 2.44E+07

Gomphonema acuminatum 1 2 .005 1.83E+07

Gomphonema consector 0 3 .005 1.83E+07

Gomphonema gracile 2 1 .005 1.83E+07

Gomphonema subclavatum var. commutatum 2 0 .004 1.22E+07

Gomphonema (GV) 6 0 .011 3.67E+07

Gomphonema sp. 0 3 .005 1.83E+07

Navicula atomus var. permitis 34 35 .126 4.22E+08

Navicula glomus 2 1 .005 1.83E+07

Navicula lanceolata 1 6 .013 4.28E+07

Navicula minima 18 12 .055 1.83E+08

Navicula pelliculosa 6 5 .020 6.72E+07

Navicula pseudoventralis 12 19 .057 1.89E+08

Navicula seminuloides 6 3 .016 5.50E+07

Navicula tripunctata 0 2 .004 1.22E+07

Navicula (GV) (short) 16 6 .040 1.34E+08

Navicula sp. 6 17 .042 1.41E+08

Nitzschia amphibia 2 2 .007 2.44E+07

Nitzschia palea 1 0 .002 6.11E+06

Pinnularia cuneicephala 0 1 .002 6.11E+06

Pseudostaurosira brevistrata + vars. 10 4 .026 8.55E+07

Rhopalodia gibba 0 1 .002 6.11E+06

Sellaphora bacillum 0 1 .002 6.11E+06

Sellaphora pupula 1 0 .002 6.11E+06

Sellaphora mutata 0 2 .004 1.22E+07

Sellaphora rectangularis 2 2 .007 2.44E+07

Staurosira construens 14 29 .079 2.63E+08

Staurosira construens var. venter 12 21 .060 2.02E+08

Staurosira elliptica 23 19 .077 2.57E+08

Staurosirella leptostauron 0 1 .002 6.11E+06

Staurosirella leptostauron var. dubia 1 0 .002 6.11E+06

Staurosirella pinnata 23 14 .068 2.26E+08

Stephanodiscus minutulus 0 1 .002 6.11E+06

Synedra rumpens 1 0 .002 6.11E+06

Synedra rumpens var. familaris 2 2 .007 2.44E+07

Tabellaria fenestrata 0 1 .002 6.11E+06

Tabellaria flocculosa str. IIIp 0 1 .002 6.11E+06

Tabellaria sp. 0 1 .002 6.11E+06

Unknown (raphid) 1 1 .004 1.22E+07

Unknown 3 1 .007 2.44E+07

TOTAL 271.5 274 1.000 3.33E+09

Chrysophyte cysts 3 5 4.89E+07

Scenedesmus coenobia 8 7 9.17E+07

Pediastrum coenobia 0 2 1.22E+07
106 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 70–72 cm

Achnanthidium exiguum 3 0 0.005 1.17E+07

Achnanthidium minutissima + vars. 18 17 .061 1.36E+08

Aulacoseira ambigua 4 3 .012 2.73E+07

Aulacoseira (VV) 0 1 .002 3.89E+06

Cocconeis placentula (RV) 0 1 .002 3.89E+06

Caloneis ventricosa 1 0 .002 3.89E+06

Cyclotella bodanica var. lemanica 0 1 .002 3.89E+06

Cyclotella comensis 1 0 .002 3.89E+06

Cyclotella glomerata 2 0 .003 7.79E+06

Cyclotella stelligera 2 0 .003 7.79E+06

Cymbella angustata 1 0 .002 3.89E+06

Cymbella sp. 1 1 .003 7.79E+06

Epithemia turgida 0 1 .002 3.89E+06

Eunotia praerupta 0 1 .002 3.89E+06

Fragilaria capucina + vars. 3 5 .014 3.11E+07

Fragilaria cf. oldenburgiana 1 0 .002 3.89E+06

Fragilaria radians 0 1 .002 3.89E+06

Fragilaria vaucheriae 1 1 .003 7.79E+06

Geissleria ignota var. palustris 2 0 .003 7.79E+06

Gomphonema gracile 1 0 .002 3.89E+06

Gomphonema truncatum 0 1 .002 3.89E+06

Gomphonema (GV) 3 0 .005 1.17E+07

Gomphonema sp. 0 3 .005 1.17E+07

Navicula atomus var. permitis 36 28 .111 2.49E+08

Navicula explanata 0 1 .002 3.89E+06

Navicula glomus 4 10 .024 5.45E+07

Navicula lanceolata 1 2 .005 1.17E+07

Navicula latelongitudinalis 0 1 .002 3.89E+06

Navicula minima 9 8 .030 6.62E+07

Navicula pelliculosa 11 15 .045 1.01E+08

Navicula pseudoventralis 28 15 .075 1.67E+08

Navicula seminuloides 1 0 .002 3.89E+06

Navicula tripunctata 1 1 .003 7.79E+06

Navicula (GV) (short) 45 10 .096 2.14E+08

Navicula sp. 3 3 .010 2.34E+07

Nitzschia amphibia 0 3 .005 1.17E+07

Nitzschia palea 2 1 .005 1.17E+07

Nitzschia sp. 1 0 .002 3.89E+06

Pinnularia sp. 1 4 .009 1.95E+07

Pseudostaurosira brevistrata + vars. 29 22 .089 1.99E+08

Sellaphora rectangularis 1 1 .003 7.79E+06

Sellaphora seminulum 2 1 .005 1.17E+07

Sellaphora vitabunda 0 2 .003 7.79E+06

Staurosira construens 16 39 .096 2.14E+08

Staurosira construens var. venter 25 20 .078 1.75E+08

Staurosira elliptica 15 19 .059 1.32E+08

Staurosirella leptostauron var. dubia 2 2 .007 1.56E+07

Staurosirella pinnata 14 3 .030 6.62E+07

Staurosirella pinnata var. lancettula 4 2 .010 2.34E+07

Stephanodiscus niagarae 0 2 .003 7.79E+06

Synedra parasitica 2 0 .003 7.79E+06

Synedra rumpens 2 0 .003 7.79E+06

Synedra rumpens var. familaris 2 1 .005 1.17E+07

Synedra ulna 1 0 .002 3.89E+06

Synedra (GV) 0 1 .002 3.89E+06

Tabellaria fenestrata 0 2 .003 7.79E+06

Unknown (raphid) 1 1 .003 7.79E+06

Unknown 0 1 .002 3.89E+06

TOTAL 308 266 1.000 2.23E+09

Chrysophyte scales 1 1 7.79E+06

Chrysophyte cysts 1 1 7.79E+06

Scenedesmus coenobia 1 5 2.34E+07

Sponge spicule 1 0 3.89E+06
Table A8 107

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Number 3 Number 4 Proportion

Number/g 

dry 

sediment

MB-1B, 80–82 cm

Achnanthidium exiguum 1 00 1 0.001 0.00E+00

Achnanthidium minutissima + vars. 6 9 17 32 .047 5.85E+07

Asterionella formosa 0 10 1 .001 2.25E+06

Asterionella ralfsii var. americana 0 00 0 .000 0.00E+00

Aulacoseira ambigua 1 53 9 .013 1.80E+07

Brachysira vitrea 0 20 2 .003 4.50E+06

Cocconeis placentula var. lineata 0 10 1 .001 2.25E+06

Cyclotella glomerata 0 20 2 .003 4.50E+06

Cyclotella sp. 2 00 2 .003 0.00E+00

Cymbella angustata 0 11 2 .003 4.50E+06

Cymbella cistula 2 11 4 .006 4.50E+06

Cymbella sp. 1 20 3 .004 4.50E+06

Encyonema silesiacum 0 11 2 .003 4.50E+06

Epithemia sorex 0 02 2 .003 4.50E+06

Epithemia turgida 0 04 4 .006 9.00E+06

Eunotia praerupta 3 0 1.5 5 .007 3.38E+06

Eunotia sp. 0 1 .5 2 .002 3.38E+06

Fragilaria capucina + vars. 6 8 10 24 .035 4.05E+07

Fragilaria crotonensis 0 30 3 .004 6.75E+06

Fragilaria vaucheriae 2 00 2 .003 0.00E+00

Geissleria ignota var. palustris 0 30 3 .004 6.75E+06

Gomphonema acuminatum 0 20 2 .003 4.50E+06

Gomphonema consector 1 01 2 .003 2.25E+06

Gomphonema gracile 1 23 6 .009 1.13E+07

Gomphonema parvulum f. micropus 0 01 1 .001 2.25E+06

Gomphonema tenellum 2 41 7 .010 1.13E+07

Gomphonema truncatum 2 00 2 .003 0.00E+00

Gomphonema pseudosphaerophorum 0 01 1 .001 2.25E+06

Gomphonema sp. 2 2 7 11 .016 2.03E+07

Navicula atomus var. permitis 31 26 41 98 .144 1.51E+08

Navicula cryptotenella 0 01 1 .001 2.25E+06

Navicula glomus 5 1 6 12 .018 1.58E+07

Navicula lanceolata 6 4 3 13 .019 1.58E+07

Navicula minima 12 2 11 25 .037 2.93E+07

Navicula pelliculosa 8 11 13 32 .047 5.40E+07

Navicula pseudoventralis 10 6 27 43 .063 7.43E+07

Navicula seminuloides 0 10 1 .001 2.25E+06

Navicula tripunctata 0 13 4 .006 9.00E+06

Navicula (GV) (short) 6 18 15 39 .057 7.43E+07

Navicula sp. 1 5 6 12 .018 2.48E+07

Neidium iridis 0 01 1 .001 2.25E+06

Nitzschia amphibia 0 31 4 .006 9.00E+06

Nitzschia palea .5 2 2.5 5 .007 1.01E+07

Nitzschia sp. 0 15 6 .009 1.35E+07

Pseudostaurosira brevistrata + vars. 4 20 4 28 .041 5.40E+07

Rhopalodia gibberula var. vanheurckii 0 10 1 .001 2.25E+06

Sellaphora pupula 0 01 1 .001 2.25E+06

Sellaphora rectangularis 0 01 1 .001 2.25E+06

Sellaphora vitabunda 2 02 4 .006 4.50E+06

Stauroneis phoenicenteron f. gracilis 1 00 1 .001 0.00E+00

Stauroneis sp. 1 00 1 .001 0.00E+00

Staurosira construens 6 34 9 49 .072 9.68E+07

Staurosira construens var. venter 8 47 10 65 .095 1.28E+08

Staurosira elliptica 16 15 20 51 .075 7.88E+07

Staurosirella leptostauron 0 10 1 .001 2.25E+06

Staurosirella pinnata 8 13 7 28 .041 4.50E+07

Synedra rumpens 1 21 4 .006 6.75E+06

Synedra rumpens var. familaris 1 12 4 .006 6.75E+06

Synedra (GV) 0 02 2 .003 4.50E+06

Tabellaria fenestrata 1 01 2 .003 2.25E+06

Tabellaria (central area) 1 0 0 1 .001 0.00E+00

Unknown (raphid) 1 0 2 3 .004 4.50E+06

Unknown 0 2 0 2 .003 4.50E+06

TOTAL 162.5 267 252.5 682 1.000 1.17E+09

Chrysophyte cysts 1 2 1 4 6.75E+06

Scenedesmus coenobia 2 7 5 14 2.70E+07

Sponge spicule 1 1 0 2 2.25E+06

Zooplankton parts 1 1 0 2 2.25E+06
108 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-1B, 90–92 cm

Achnanthidium exiguum 0 3 0.006 9.09E+06

Achnanthidium minutissima + vars. 8 13 .041 6.36E+07

Amphora ovalis var. affinis 0 1 .002 3.03E+06

Asterionella formosa 0 1 .002 3.03E+06

Aulacoseira ambigua 1 0 .002 3.03E+06

Aulacoseira (VV) 2 0 .004 6.06E+06

Brachysira vitrea 2 0 .004 6.06E+06

Cocconeis placentula var. lineata 1 1 .004 6.06E+06

Cocconeis placentula 1 0 .002 3.03E+06

Cyclotella atomus 1 0 .002 3.03E+06

Cyclotella bodanica var. lemanica 1 0 .002 3.03E+06

Cyclotella michiganiana 2 0 .004 6.06E+06

Cyclotella stelligera 0 1 .002 3.03E+06

Cymbella angustata 1 2 .006 9.09E+06

Cymbella cistula 0 1 .002 3.03E+06

Cymbella cuspidata 1 0 .002 3.03E+06

Cymbella sp. 0 4 .008 1.21E+07

Encyonema silesiacum 5 1 .012 1.82E+07

Epithemia arcus 1 0 .002 3.03E+06

Eunotia incisa 0 2.5 .005 7.58E+06

Eunotia arcus 1 0 .002 3.03E+06

Eunotia praerupta 0 .5 .001 1.52E+06

Eunotia sp. .5 2 .005 7.58E+06

Fragilaria capucina + vars. 0 3 .006 9.09E+06

Fragilaria vaucheriae 0 3 .006 9.09E+06

Geissleria ignota var. palustris 2 2 .008 1.21E+07

Gomphonema consector 1 0 .002 3.03E+06

Gomphonema gracile 4 3 .014 2.12E+07

Gomphonema subtile var. sagitta 1 0 .002 3.03E+06

Gomphonema truncatum 1 0 .002 3.03E+06

Gomphonema (GV) 2 0 .004 6.06E+06

Gomphonema sp. 1 2 .006 9.09E+06

Navicula atomus var. permitis 24 36 .118 1.82E+08

Navicula glomus 0 2 .004 6.06E+06

Navicula graciloides 0 1 .002 3.03E+06

Navicula lanceolata 4 3 .014 2.12E+07

Navicula latelongitudinalis 0 3 .006 9.09E+06

Navicula minima 5 11 .032 4.85E+07

Navicula pelliculosa 18 5 .045 6.97E+07

Navicula pseudoventralis 9 8 .034 5.15E+07

Navicula radiosa 1 0 .002 3.03E+06

Navicula radiosafallax 1 0 .002 3.03E+06

Navicula tripunctata 0 1 .002 3.03E+06

Navicula viridula 1 0 .002 3.03E+06

Navicula (GV) (short) 18 18 .071 1.09E+08

Navicula sp. 10 8 .036 5.46E+07

Nitzschia amphibia 0 2.5 .005 7.58E+06

Nitzschia fonticola 1 1 .004 6.06E+06

Nitzschia palea 1.5 2 .007 1.06E+07

Nitzschia sp. 0 2 .004 6.06E+06

Pinnularia viridis 1 1 .004 6.06E+06

Planothidium lanceolata 1 0 .002 3.03E+06

Pseudostaurosira brevistrata + vars. 28 4 .063 9.70E+07

Sellaphora bacillum 0 1 .002 3.03E+06

Sellaphora pupula 0 1 .002 3.03E+06

Sellaphora vitabunda 0 4 .008 1.21E+07

Sellaphora rectangularis 1 2 .006 9.09E+06

Staurosira construens 28 24 .103 1.58E+08

Staurosira construens var. venter 20 34 .107 1.64E+08

Staurosira elliptica 18 9 .053 8.18E+07

Staurosirella leptostauron var. dubia 0 2 .004 6.06E+06

Staurosirella pinnata 10 4 .028 4.24E+07

Synedra demerarae 1 0 .002 3.03E+06

Synedra delicatissima 1 0 .002 3.03E+06

Synedra rumpens 1 2 .006 9.09E+06

Synedra rumpens var. familaris 5 9 .028 4.24E+07

Synedra tenera 0 2 .004 6.06E+06

Synedra ulna 0 2 .004 6.06E+06

Synedra (GV) 1 0 .002 3.03E+06

Synedra sp. 1 0 .002 3.03E+06

Tabellaria flocculosa str. IIIp 0 1 .002 3.03E+06

Unknown (raphid) 1 2 .006 9.09E+06

Unknown 1 0 .002 3.03E+06

TOTAL 253 253.5 1.000 1.53E+09

Chrysophyte cysts 1 2 9.09E+06

Scenedesmus coenobia 4 8 3.64E+07
Table A8 109

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

MB-3, 0–2 cm

Achnanthidium conspicua 0 1 0.002 2.14E+06

Achnanthidium exiguum 1 0 .002 2.14E+06

Achnanthidium exiguum var. heterovalvum 0 1 .002 2.14E+06

Achnanthidium lewisiana 1 0 .002 2.14E+06

Achnanthidium minutissima + vars. 2 11 .031 2.78E+07

Amphora ovalis var. affinis 0 1 .002 2.14E+06

Aulacoseira ambigua 1 3 .010 8.54E+06

Aulacoseira sp. 0 1 .002 2.14E+06

Brachysira sp. 1 0 .002 2.14E+06

Cocconeis placentula var+A22. euglypta 0 6 .014 1.28E+07

Cocconeis placentula var. lineata 3 6 .022 1.92E+07

Cocconeis placentula (RV) 1 0 .002 2.14E+06

Cyclotella bodanica var. affinis 0 1 .002 2.14E+06

Cyclotella michiganiana 0 1 .002 2.14E+06

Cyclotella sp. 0 2 .005 4.27E+06

Cymbella angustata 2 1 .007 6.41E+06

Cymbella cistula 0 2 .005 4.27E+06

Cymbella sp. 2 1 .007 6.41E+06

Epithemia turgida 0 2 .005 4.27E+06

Eunotia incisa 1 3 .010 8.54E+06

Eunotia sp. 1 3 .010 8.54E+06

Fragilaria capucina + vars. 32 48 .192 1.71E+08

Fragilaria crotonensis 2 10 .029 2.56E+07

Fragilaria vaucheriae 1 0 .002 2.14E+06

Gomphonema consector 1 0 .002 2.14E+06

Gomphonema tenellum 1 0 .002 2.14E+06

Gomphonema truncatum 1 0 .002 2.14E+06

Gomphonema (GV) 8 6 .034 2.99E+07

Gomphonema sp. 1 1 .005 4.27E+06

Hantzschia sp. 0 1 .002 2.14E+06

Navicula crytotenella 0 2 .005 4.27E+06

Navicula atomus var. permitis 8 0 .019 1.71E+07

Navicula lanceolata 1 1 .005 4.27E+06

Navicula minima 0 10 .024 2.14E+07

Navicula pseudoventralis 3 1 .010 8.54E+06

Navicula radiosa 0 1 .002 2.14E+06

Navicula radiosafallax 0 2 .005 4.27E+06

Navicula schadei 2 0 .005 4.27E+06

Navicula seminuloides 5 0 .012 1.07E+07

Navicula ventralis 1 0 .002 2.14E+06

Navicula (GV) 10 0 .024 2.14E+07

Navicula sp. 3 5 .019 1.71E+07

Neidium sp. 0 1 .002 2.14E+06

Nitzschia amphibia 1 1 .005 4.27E+06

Nitzschia dissipata 0 2 .005 4.27E+06

Nitzschia palea 3 0 .007 6.41E+06

Nitzschia sp. 3 2 .012 1.07E+07

Pseudostaurosira brevistrata + vars. 3 7 .024 2.14E+07

Sellophora rectangularis 0 2 .005 4.27E+06

Sellaphora vitabunda 0 1 .002 2.14E+06

Stauroneis sp. 1 0 .002 2.14E+06

Staurosira construens 15 47 .149 1.32E+08

Staurosira construens var. venter 4 30 .082 7.26E+07

Staurosira elliptica 3 .007 6.41E+06

Staurosirella pinnata 33 15 .115 1.03E+08

Synedra rumpens var. familaris 1 0 .002 2.14E+06

Synedra ulna 0 4 .010 8.54E+06

Unknown (raphid) 4 2 .014 1.28E+07

Unknown 0 2 .005 4.27E+06

TOTAL 167 250 1.000 8.89E+08

Chrysophyte scales 0 1 2.14E+06

Chrysophyte cysts 2 5 1.50E+07

Scenedesmus coenobia 8 0 1.71E+07

Tetraedron coenobia 2 0 4.27E+06

Pediastrum coenobia 1 0 2.14E+06

Sponge spicule 1 0 2.14E+06
110 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 4–6 cm

Achnanthidium exiguum var. heterovalvum 2 0.008 1.76E+06

Achnanthidium minutissima + vars. 20 .080 1.76E+07

Achnanthidium sp. 5 .020 4.40E+06

Amphora montana 1 .004 8.79E+05

Aulacoseira ambigua 2 .008 1.76E+06

Cocconeis placentula var. euglypta 3 .012 2.64E+06

Cocconeis placentula var. lineata 8 .032 7.04E+06

Cyclotella sp. 1 .004 8.79E+05

Cymbella cistula 1 .004 8.79E+05

Encyonema silesiacum 2 .008 1.76E+06

Epithemia turgida 1 .004 8.79E+05

Eunotia sp. 3 .012 2.64E+06

Fragilaria capucina + vars. 2 .008 1.76E+06

Fragilaria crotonensis 3 .012 2.64E+06

Gomphonema (GV) 4 .016 3.52E+06

Gomphonema sp. 2 .008 1.76E+06

Navicula cryptotenella 2 .008 1.76E+06

Navicula glomus 3 .012 2.64E+06

Navicula lanceolata 1 .004 8.79E+05

Navicula minima 20 .080 1.76E+07

Navicula pseudoventralis 2 .008 1.76E+06

Navicula radiosafallax 1 .004 8.79E+05

Navicula seminuloides 1 .004 8.79E+05

Navicula sp. 7 .028 6.16E+06

Nitzschia amphibia 4 .016 3.52E+06

Nitzschia sp. 4 .016 3.52E+06

Pinnularia mormonorum 1 .004 8.79E+05

Pinnularia sp. 4 .016 3.52E+06

Pseudostaurosira brevistrata + vars. 2 .008 1.76E+06

Sellaphora parapupula 1 .004 8.79E+05

Sellaphora rectangularis 3 .012 2.64E+06

Sellaphora vitabunda 1 .004 8.79E+05

Staurosira construens 76 .304 6.68E+07

Staurosira construens var. venter 31 .124 2.73E+07

Staurosirella leptostauron 1 .004 8.79E+05

Staurosirella pinnata 11 .044 9.67E+06

Unknown (raphid) 10 .040 8.79E+06

Unknown 4 .016 3.52E+06

Total 250 1.000 2.20E+08

Chrysophyte scales 2 1.76E+06

Chrysophyte cysts 1 8.79E+05
Table A8 111

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 10–12 cm

Achnanthidium exiguum var. heterovalvum 3 0.012 3.86E+06

Achnanthidium minutissima + vars. 14 .056 1.80E+07

Achnanthidium sp. 1 .004 1.29E+06

Aulacoseira ambigua 1 .004 1.29E+06

Cocconeis placentula var. euglypta 4 .016 5.15E+06

Cocconeis placentula var. lineata 3 .012 3.86E+06

Cyclotella sp. 2 .008 2.57E+06

Cymbella angustata 3 .012 3.86E+06

Cymbella cesatii 1 .004 1.29E+06

Cymbella cistula 2 .008 2.57E+06

Cymbella heteropleura var. subrostrata 1 .004 1.29E+06

Cymbella muelleri var. ventricosa 1 .004 1.29E+06

Encyonema silesiacum 3 .012 3.86E+06

Epithemia turgida 2 .008 2.57E+06

Eunotia arcus 1 .004 1.29E+06

Eunotia incisa 1 .004 1.29E+06

Eunotia sp. 3 .012 3.86E+06

Fragilaria capucina + vars. 5 .020 6.44E+06

Fragilaria crotonensis 7 .028 9.01E+06

Fragilaria sp. 5 .020 6.44E+06

Gomphonema (GV) 8 .032 1.03E+07

Gomphonema angustata 1 .004 1.29E+06

Gomphonema clevei 3 .012 3.86E+06

Gomphonema sp. 1 .004 1.29E+06

Navicula aurora 2 .008 2.57E+06

Navicula cryptotenella 2 .008 2.57E+06

Navicula glomus 1 .004 1.29E+06

Navicula ignota var. palustris 5 .020 6.44E+06

Navicula minima 19 .076 2.45E+07

Navicula pseudoventralis 1 .004 1.29E+06

Navicula radiosa 2 .008 2.57E+06

Navicula radiosafallax 1 .004 1.29E+06

Navicula seminuloides 1 .004 1.29E+06

Navicula sp. 9 .036 1.16E+07

Nitzschia amphibia 2 .008 2.57E+06

Nitzschia dissipata 2 .008 2.57E+06

Nitzschia sp. 1 .004 1.29E+06

Pseudostaurosira brevistrata + vars. 1 .004 1.29E+06

Pinnularia mesolepta 1 .004 1.29E+06

Sellaphora laevissima 1 .004 1.29E+06

Sellaphora rectangularis 1 .004 1.29E+06

Staurosira construens 20 .080 2.57E+07

Staurosira construens v. binodis 1 .004 1.29E+06

Staurosira construens var. venter 57 .228 7.34E+07

Staurosirella pinnata 37 .148 4.76E+07

Stephanodiscus medius 1 .004 1.29E+06

Stephanodiscus sp. 1 .004 1.29E+06

Tabellaria sp. .5 .002 6.44E+05

Unknown (raphid) 5 .020 6.44E+06

Total 250.5 1.000 3.19E+08

Chrysophyte scales 1 1.29E+06

Chrysophyte cysts 2 2.57E+06
112 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 14–16 cm

Achnanthidium exiguum var. heterovalvum 3 0.012 6.35E+06

Achnanthidium minutissima + vars. 9 .036 1.90E+07

Achnanthidium sp. 5 .020 1.06E+07

Aulacoseira ambigua 2 .008 4.23E+06

Caloneis silicula 1 .004 2.12E+06

Cocconeis placentula var. euglypta 4 .016 8.46E+06

Cocconeis placentula var. lineata 5 .020 1.06E+07

Cymbella angustata 2 .008 4.23E+06

Cymbella cesatii 1 .004 2.12E+06

Cymbella cistula 1 .004 2.12E+06

Cymbella heteropleura var. subrostrata 1 .004 2.12E+06

Cymbella sp. 4 .016 8.46E+06

Encyonema silesiacum 1 .004 2.12E+06

Epithemia arcus 1 .004 2.12E+06

Epithemia turgida 1 .004 2.12E+06

Eunotia arcus 1 .004 2.12E+06

Eunotia incisa 1 .004 2.12E+06

Fragilaria capucina + vars. 3 .012 6.35E+06

Fragilaria crotonensis 4 .016 8.46E+06

Fragilaria sp. 2 .008 4.23E+06

Gomphonema (GV) 6 .024 1.27E+07

Gomphonema angustata 1 .004 2.12E+06

Gomphonema clevei 3 .012 6.35E+06

Gomphonema sp. 1 .004 2.12E+06

Navicula glomus 3 .012 6.35E+06

Navicula ignota v. palustris 2 .008 4.23E+06

Navicula laterostrata 2 .008 4.23E+06

Navicula minima 15 .060 3.17E+07

Navicula pseudoventralis 2 .008 4.23E+06

Navicula sp. 6 .024 1.27E+07

Neidium sp. 2 .008 4.23E+06

Nitzschia dissipata 2 .008 4.23E+06

Nitzschia sp. 1 .004 2.12E+06

Pseudostaurosira brevistrata + vars. 5 .020 1.06E+07

Pinnularia mesolepta 1 .004 2.12E+06

Sellaphora rectangularis 2 .008 4.23E+06

Stauroneis phoenocenteron var. braunii 1 .004 2.12E+06

Staurosira construens 56 .223 1.18E+08

Staurosira construens var. venter 43 .171 9.10E+07

Staurosirella pinnata 35 .139 7.41E+07

Stephanodiscus niagarae 1 .004 2.12E+06

Synedra rumpens 1 .004 2.12E+06

Synedra sp. 1 .004 2.12E+06

Synedra ulna 1 .004 2.12E+06

Unknown (raphid) 5 .020 1.06E+07

Unknown 1 .004 2.12E+06

Total 251 1.000 5.27E+08

Chrysophyte scales 2 4.23E+06
Table A8 113

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 20–22 cm

Achnanthidium exiguum var. heterovalvum 5 0.020 1.74E+07

Achnanthidium minutissima + vars. 6 .024 2.08E+07

Achnanthidium sp. 2 .008 6.94E+06

Amphora ovalis 1 .004 3.47E+06

Aulacoseira ambigua 2 .008 6.94E+06

Brachysira vitrea 1 .004 3.47E+06

Cavinula variostraita 1 .004 3.47E+06

Cocconeis placentula var. euglypta 1 .004 3.47E+06

Cocconeis placentula var. lineata 2 .008 6.94E+06

Craticula cuspidata 1 .004 3.47E+06

Cyclotella rossii 1 .004 3.47E+06

Cyclotella sp. 2 .008 6.94E+06

Cymbella angustata 1 .004 3.47E+06

Cymbella sp. 2 .008 6.94E+06

Encyonema silesiacum 2 .008 6.94E+06

Epithemia arcus 2 .008 6.94E+06

Epithemia sp. 2 .008 6.94E+06

Eunotia incisa 2 .008 6.94E+06

Fragilaria capucina + vars. 6 .024 2.08E+07

Fragilaria crotonensis 11 .044 3.82E+07

Geissleria kriegerii 1 .004 3.47E+06

Gomphonema (GV) 2 .008 6.94E+06

Gomphonema angustata 4 .016 1.39E+07

Gomphonema brebissonii 1 .004 3.47E+06

Gomphonema gracile 1 .004 3.47E+06

Gomphonema sp. 2 .008 6.94E+06

Navicula atomus var. permitis 3 .012 1.04E+07

Navicula aurora 2 .008 6.94E+06

Navicula glomus 2 .008 6.94E+06

Navicula ignota var. palustris 2 .008 6.94E+06

Navicula laterostrata 2 .008 6.94E+06

Navicula minima 8 .032 2.78E+07

Navicula radiosa 2 .008 6.94E+06

Navicula radiosafallax 1 .004 3.47E+06

Navicula sp. 7 .028 2.43E+07

Neidium sp. 2 .008 6.94E+06

Nitzschia amphibia 2 .008 6.94E+06

Nitzschia sp. 3 .012 1.04E+07

Pinnularia mormonorum 2 .008 6.94E+06

Pseudostaurosira brevistrata + vars. 10 .040 3.47E+07

Rhopalodia gibba 1 .004 3.47E+06

Sellaphora mutata 3 .012 1.04E+07

Sellaphora parapupula 2 .008 6.94E+06

Sellaphora rectangularis 3 .012 1.04E+07

Staurosira construens 64 .254 2.22E+08

Staurosira construens var. venter 43 .171 1.49E+08

Staurosirella pinnata 21 .083 7.29E+07

Unknown (raphid) 3 .012 1.04E+07

Total 252 1.000 8.75E+08

Chrysophyte cysts 4 1.39E+07
114 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 24–26 cm

Achnanthidium conspicua 1 0.004 2.75E+06

Achnanthidium exiguum var. heterovalvum 5 .020 1.38E+07

Achnanthidium minutissima + vars. 9 .036 2.48E+07

Amphora ovalis 1 .004 2.75E+06

Asterionella formosa .5 .002 1.38E+06

Aulacoseira ambigua 5 .020 1.38E+07

Cocconeis placentula var. euglypta 1 .004 2.75E+06

Cocconeis placentula var. lineata 6 .024 1.65E+07

Cyclotella michiganiana 2 .008 5.51E+06

Cyclotella rossii 1 .004 2.75E+06

Cyclotella stelligera 2 .008 5.51E+06

Cymbella cesatii 5 .020 1.38E+07

Cymbella sp. 3 .012 8.26E+06

Encyonema silesiacum 3 .012 8.26E+06

Eunotia monodon 1 .004 2.75E+06

Eunotia sp. 2 .008 5.51E+06

Fragilaria capucina + vars. 6 .024 1.65E+07

Fragilaria crotonensis 3 .012 8.26E+06

Fragilaria vaucheriae 1 .004 2.75E+06

Gomphonema (GV) 4 .016 1.10E+07

Gomphonema angustata 2 .008 5.51E+06

Gomphonema parvulum 1 .004 2.75E+06

Gomphonema sp. 1 .004 2.75E+06

Navicula aurora 1 .004 2.75E+06

Navicula atomus var. permitis 2 .008 5.51E+06

Navicula cryptotenella 1 .004 2.75E+06

Navicula glomus 1 .004 2.75E+06

Navicula graciloides 2 .008 5.51E+06

Navicula ignota v. palustris 1 .004 2.75E+06

Navicula lanceolata 1 .004 2.75E+06

Navicula laterostrata 3 .012 8.26E+06

Navicula minima 19 .076 5.23E+07

Navicula radiosafallax 2 .008 5.51E+06

Navicula sp. 6 .024 1.65E+07

Neidium iridis 3 .012 8.26E+06

Neidium sp. 1 .004 2.75E+06

Nitzschia amphibia 1 .004 2.75E+06

Pinnularia mormonorum 1 .004 2.75E+06

Pinnularia sp. 1 .004 2.75E+06

Pseudostaurosira brevistrata + vars. 12 .048 3.31E+07

Sellaphora mutata 1 .004 2.75E+06

Sellaphora rectangularis 1 .004 2.75E+06

Sellaphora seminulum 1 .004 2.75E+06

Staurosira construens 80 .320 2.20E+08

Staurosira construens var. binodis 2 .008 5.51E+06

Staurosira construens var. venter 7 .028 1.93E+07

Staurosirella pinnata 31 .124 8.54E+07

Staurosirella pinnata v. lancettula 1 .004 2.75E+06

Synedra sp. 1 .004 2.75E+06

Tabellaria sp. .5 .002 1.38E+06

Unknown (raphid) 1 .004 2.75E+06

Total 250 1.000 6.89E+08

Chrysophyte cysts 2 5.51E+06
Table A8 115

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 30–32 cm

Achnanthidium exiguum var. heterovalvum 4 0.016 4.53E+06

Achnanthidium minutissima + vars. 12 .048 1.36E+07

Achnanthidium sp. 3 .012 3.40E+06

Amphora ovalis 1 .004 1.13E+06

Aulacoseira ambigua 15 .060 1.70E+07

Aulacoseira italica 6 .024 6.79E+06

Cocconeis naviculiformis 1 .004 1.13E+06

Cocconeis placentula var. lineata 5 .020 5.66E+06

Craticula cuspidata 1 .004 1.13E+06

Cyclotella michiganiana 5 .020 5.66E+06

Cyclotella stelligera 4 .016 4.53E+06

Cyclotella sp. 1 .004 1.13E+06

Cymbella angustata 2 .008 2.26E+06

Cymbella cistula 1 .004 1.13E+06

Cymbella sp. 4 .016 4.53E+06

Encyonema silesiacum 2 .008 2.26E+06

Epithemia turgida 1 .004 1.13E+06

Eunotia arcus 2 .008 2.26E+06

Eunotia incisa 4 .016 4.53E+06

Eunotia sp. 2 .008 2.26E+06

Fragilaria capucina + vars. 3 .012 3.40E+06

Fragilaria crotonensis 10 .040 1.13E+07

Fragilaria vaucheriae 1 .004 1.13E+06

Gomphonema (GV) 4 .016 4.53E+06

Gomphonema acuminatum var. pusilla 2 .008 2.26E+06

Gomphonema angustata 2 .008 2.26E+06

Gomphonema sp. 3 .012 3.40E+06

Navicula aurora 5 .020 5.66E+06

Navicula cryptotenella 1 .004 1.13E+06

Navicula explanata 1 .004 1.13E+06

Navicula glomus 1 .004 1.13E+06

Navicula graciloides 1 .004 1.13E+06

Navicula ignota v. palustris 1 .004 1.13E+06

Navicula laterostrata 3 .012 3.40E+06

Navicula minima 12 .048 1.36E+07

Navicula obdurata 2 .008 2.26E+06

Navicula radiosa 2 .008 2.26E+06

Navicula radiosafallax 2 .008 2.26E+06

Navicula sp. 11 .044 1.25E+07

Neidium sp. 3 .012 3.40E+06

Nitzschia amphibia 2 .008 2.26E+06

Pseudostaurosira brevistrata + vars. 2 .008 2.26E+06

Sellaphora rectangularis 4 .016 4.53E+06

Stauroneis sp. 1 .004 1.13E+06

Staurosira construens 38 .152 4.30E+07

Staurosira construens var. venter 30 .120 3.40E+07

Staurosirella pinnata 12 .048 1.36E+07

Staurosirella pinnata v. lancettula 4 .016 4.53E+06

Stephanodiscus niagarae 1 .004 1.13E+06

Stephanodiscus sp. 1 .004 1.13E+06

Synedra sp. 1 .004 1.13E+06

Synedra ulna 1 .004 1.13E+06

Tabellaria sp. .5 .002 5.66E+05

Unknown (raphid) 3 .012 3.40E+06

Unknown 4 .016 4.53E+06

Total 250.5 1.000 2.84E+08

Chrysophyte cysts 5 5.66E+06
116 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 34–36 cm

Achnanthidium exiguum var. heterovalvum 8 0.032 2.48E+07

Achnanthidium minutissima + vars. 14 .056 4.34E+07

Achnanthidium stewartii 3 .012 9.30E+06

Achnanthidium sp. 3 .012 9.30E+06

Amphora ovalis 1 .004 3.10E+06

Aulacoseira ambigua 7 .028 2.17E+07

Aulacoseira italica 3 .012 9.30E+06

Cocconeis disculus 1 .004 3.10E+06

Cocconeis placentula var. lineata 5 .020 1.55E+07

Craticula cuspidata 1 .004 3.10E+06

Cyclotella sp. 1 .004 3.10E+06

Cyclotella stelligera 5 .020 1.55E+07

Cymbella angustata 2 .008 6.20E+06

Cymbella cesatii 1 .004 3.10E+06

Cymbella sp. 1 .004 3.10E+06

Encyonema silesiacum 4 .016 1.24E+07

Epithemia arcus 1 .004 3.10E+06

Eunotia arcus 3 .012 9.30E+06

Eunotia incisa 1 .004 3.10E+06

Fragilaria capucina + vars. 3 .012 9.30E+06

Fragilaria crotonensis 4 .016 1.24E+07

Fragilaria radians 2 .008 6.20E+06

Fragilaria vaucheriae 1 .004 3.10E+06

Gomphonema (GV) 2 .008 6.20E+06

Gomphonema acuminatum 1 .004 3.10E+06

Gomphonema angustata 7 .028 2.17E+07

Navicula aurora 1 .004 3.10E+06

Navicula glomus 1 .004 3.10E+06

Navicula graciloides 2 .008 6.20E+06

Navicula ignota v. palustris 8 .032 2.48E+07

Navicula laterostrata 8 .032 2.48E+07

Navicula minima 9 .036 2.79E+07

Navicula obdurata 2 .008 6.20E+06

Navicula pseudoventralis 3 .012 9.30E+06

Navicula radiosa 2 .008 6.20E+06

Navicula radiosafallax 5 .020 1.55E+07

Navicula sp. 8 .032 2.48E+07

Neidium iridis 2 .008 6.20E+06

Neidium sp. 2 .008 6.20E+06

Nitzschia palea 2 .008 6.20E+06

Pseudostaurosira brevistrata + vars. 6 .024 1.86E+07

Sellaphora rectangularis 5 .020 1.55E+07

Stauroneis phoenicenteron f. gracilis 3 .012 9.30E+06

Stauroneis sp. 2 .008 6.20E+06

Staurosira construens 31 .124 9.61E+07

Staurosira construens var. venter 31 .124 9.61E+07

Staurosirella pinnata 22 .088 6.82E+07

Staurosirella pinnata v. lancettula 4 .016 1.24E+07

Stephanodiscus niagarae 1 .004 3.10E+06

Synedra sp. 1 .004 3.10E+06

Tabellaria sp. .5 .002 1.55E+06

Unknown (raphid) 4 .016 1.24E+07

Total 250.5 1.000 7.77E+08

Chrysophyte cysts 8 2.48E+07
Table A8 117

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 40–42 cm

Achnanthidium exiguum var. heterovalvum 6 0.024 9.32E+06

Achnanthidium minutissima + vars. 7 .028 1.09E+07

Achnanthidium sp. 1 .004 1.55E+06

Amphora ovalis 1 .004 1.55E+06

Aulacoseira ambigua 20 .080 3.11E+07

Aulacoseira italica 4 .016 6.21E+06

Cocconeis placentula var. lineata 7 .028 1.09E+07

Craticula cuspidata 1 .004 1.55E+06

Cyclotella bodanica var. lemanica 2 .008 3.11E+06

Cyclotella michiganiana 1 .004 1.55E+06

Cyclotella ocellata 1 .004 1.55E+06

Cymbella angustata 6 .024 9.32E+06

Cymbella cistula 7 .028 1.09E+07

Encyonema silesiacum 3 .012 4.66E+06

Epithemia sp. 5 .020 7.76E+06

Epithemia turgida 1 .004 1.55E+06

Eunotia arcus 5 .020 7.76E+06

Eunotia incisa 4 .016 6.21E+06

Eunotia sp. 5 .020 7.76E+06

Fragilaria capucina + vars. 5 .020 7.76E+06

Fragilaria crotonensis 1 .004 1.55E+06

Fragilaria vaucheriae 3 .012 4.66E+06

Gomphonema (GV) 10 .040 1.55E+07

Gomphonema acuminatum 3 .012 4.66E+06

Gomphonema affine var. insigne 1 .004 1.55E+06

Gomphonema angustata 4 .016 6.21E+06

Gomphonema tenellum 1 .004 1.55E+06

Gomphonema truncatum 1 .004 1.55E+06

Gomphonema sp. 7 .028 1.09E+07

Gyrosigma sp. 1 .004 1.55E+06

Navicula aurora 5 .020 7.76E+06

Navicula cryptotenella 3 .012 4.66E+06

Navicula glomus 1 .004 1.55E+06

Navicula graciloides 1 .004 1.55E+06

Navicula ignota v. palustris 2 .008 3.11E+06

Navicula laterostrata 3 .012 4.66E+06

Navicula minima 5 .020 7.76E+06

Navicula radiosafallax 1 .004 1.55E+06

Navicula sp. 4 .016 6.21E+06

Neidium iridis 6 .024 9.32E+06

Nitzschia sp. 1 .004 1.55E+06

Pinnularia abaujensis 1 .004 1.55E+06

Pinnularia sp. 2 .008 3.11E+06

Pseudostaurosira brevistrata + vars. 6 .024 9.32E+06

Sellaphora pupula 2 .008 3.11E+06

Sellaphora rectangularis 4 .016 6.21E+06

Stauroneis phoenicenteron f. gracilis 1 .004 1.55E+06

Staurosira construens 34 .135 5.28E+07

Staurosira construens var. venter 25 .100 3.88E+07

Staurosirella pinnata 13 .052 2.02E+07

Staurosirella pinnata v. lancettula 1 .004 1.55E+06

Synedra capitata 1 .004 1.55E+06

Synedra sp. 2 .008 3.11E+06

Unknown (raphid) 3 .012 4.66E+06

Total 251 1.000 3.90E+08

Chrysophyte cysts 2 3.11E+06
118 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 44–46 cm

Achnanthidium exiguum var. heterovalvum 9 0.036 3.38E+07

Achnanthidium minutissima + vars. 45 .179 1.69E+08

Achnanthidium sp. 2 .008 7.52E+06

Amphora ovalis 2 .008 7.52E+06

Aulacoseira ambigua 11 .044 4.13E+07

Aulacoseira italica 4 .016 1.50E+07

Cocconeis naviculiformis 1 .004 3.76E+06

Cocconeis placentula var. lineata 4 .016 1.50E+07

Cyclotella michiganiana 3 .012 1.13E+07

Cymbella angustata 2 .008 7.52E+06

Cymbella cistula 3 .012 1.13E+07

Cymbella sp. 1 .004 3.76E+06

Encyonema silesiacum 4 .016 1.50E+07

Epithemia sp. 2 .008 7.52E+06

Eunotia arcus 2 .008 7.52E+06

Eunotia incisa 5 .020 1.88E+07

Fragilaria crotonensis 4 .016 1.50E+07

Fragilaria radians 1 .004 3.76E+06

Geissleria ignota var. palustris 3 .012 1.13E+07

Gomphonema (GV) 6 .024 2.26E+07

Gomphonema affine var. insigne 1 .004 3.76E+06

Gomphonema angustata 8 .032 3.01E+07

Gomphonema gracile 2 .008 7.52E+06

Gomphonema parvulum 1 .004 3.76E+06

Gomphonema truncatum 1 .004 3.76E+06

Gomphonema sp. 6 .024 2.26E+07

Navicula aurora 1 .004 3.76E+06

Navicula biconica 2 .008 7.52E+06

Navicula cryptotenella 3 .012 1.13E+07

Navicula graciloides 1 .004 3.76E+06

Navicula lanceolata 1 .004 3.76E+06

Navicula laterostrata 4 .016 1.50E+07

Navicula minima 13 .052 4.89E+07

Navicula obdurata 1 .004 3.76E+06

Navicula pseudoventralis 5 .020 1.88E+07

Navicula radiosa 2 .008 7.52E+06

Navicula radiosafallax 1 .004 3.76E+06

Navicula sp. 8 .032 3.01E+07

Neidium iridis 1 .004 3.76E+06

Nitzschia amphibia 3 .012 1.13E+07

Nitzschia palea 2 .008 7.52E+06

Nitzschia sp. 1 .004 3.76E+06

Pinnularia abaujensis 1 .004 3.76E+06

Pinnularia mormonorum 1 .004 3.76E+06

Pinnularia sp. 1 .004 3.76E+06

Pseudostaurosira brevistrata + vars. 7 .028 2.63E+07

Sellaphora parapupula 1 .004 3.76E+06

Sellaphora rectangularis 4 .016 1.50E+07

Stauroneis sp. 1 .004 3.76E+06

Staurosira construens 10 .040 3.76E+07

Staurosira construens var. venter 22 .088 8.27E+07

Staurosirella pinnata 12 .048 4.51E+07

Staurosirella pinnata var. lancettula 1 .004 3.76E+06

Synedra acus 2 .008 7.52E+06

Synedra ulna 2 .008 7.52E+06

Tabellaria sp. 1 .004 3.76E+06

Unknown (raphid) 3 .012 1.13E+07

Total 251 1.000 9.43E+08

Chrysophyte scales 1 3.76E+06

Chrysophyte cysts 5 1.88E+07
Table A8 119

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 50–52 cm

Achnanthidium exiguum var. heterovalvum 13 0.052 3.87E+07

Achnanthidium minutissima + vars. 31 .123 9.23E+07

Aulacoseira ambigua 17 .067 5.06E+07

Aulacoseira italica 4 .016 1.19E+07

Cocconeis placentula var. lineata 3 .012 8.93E+06

Cyclotella bodanica var. lemanica 1 .004 2.98E+06

Cymbella angustata 2 .008 5.95E+06

Cymbella cistula 3 .012 8.93E+06

Cymbella sp. 2 .008 5.95E+06

Encyonema silesiacum 4 .016 1.19E+07

Epithemia turgida 1 .004 2.98E+06

Eunotia arcus 6 .024 1.79E+07

Eunotia incisa 8 .032 2.38E+07

Eunotia pectinalis 2 .008 5.95E+06

Eunotia sp. 2 .008 5.95E+06

Fragilaria capucina + vars. 5 .020 1.49E+07

Fragilaria crotonensis 2 .008 5.95E+06

Fragilaria vaucheriae 2 .008 5.95E+06

Gomphonema acuminatum 1 .004 2.98E+06

Gomphonema affine var. insigne 5 .020 1.49E+07

Gomphonema angustata 5 .020 1.49E+07

Gomphonema clevei 3 .012 8.93E+06

Gomphonema gracile 3 .012 8.93E+06

Gomphonema parvulum 1 .004 2.98E+06

Gomphonema tenellum 1 .004 2.98E+06

Gomphonema truncatum 1 .004 2.98E+06

Gomphonema sp. 9 .036 2.68E+07

Gomphonema (GV) 9 .036 2.68E+07

Navicula aurora 2 .008 5.95E+06

Navicula biconica 3 .012 8.93E+06

Navicula cryptotenella 1 .004 2.98E+06

Navicula glomus 1 .004 2.98E+06

Navicula graciloides 1 .004 2.98E+06

Navicula minima 13 .052 3.87E+07

Navicula pseudoventralis 4 .016 1.19E+07

Navicula radiosa 1 .004 2.98E+06

Navicula radiosafallax 1 .004 2.98E+06

Navicula sp. 7 .028 2.08E+07

Neidium iridis 1 .004 2.98E+06

Pinnularia sp. 1 .004 2.98E+06

Pseudostaurosira brevistrata + vars. 1 .004 2.98E+06

Sellaphora pupula 1 .004 2.98E+06

Sellaphora rectangularis 5 .020 1.49E+07

Stauroneis phoenicenteron f. gracilis 3 .012 8.93E+06

Staurosira construens 11 .044 3.27E+07

Staurosira construens var. venter 25 .099 7.44E+07

Staurosirella pinnata 6 .024 1.79E+07

Surirella sp. 1 .004 2.98E+06

Synedra acus 1 .004 2.98E+06

Synedra sp. 3 .012 8.93E+06

Synedra ulna 3 .012 8.93E+06

Tabellaria sp. 1 .004 2.98E+06

Unknown (raphid) 3 .012 8.93E+06

Total 252 1.000 7.50E+08

Chrysophyte cysts 6 1.79E+07
120 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 54–56 cm

Achnanthidium exiguum var. heterovalvum 8 0.032 4.80E+07

Achnanthidium minutissima + vars. 28 .112 1.68E+08

Achnanthidium sp. 3 .012 1.80E+07

Brachysira vitrea 1 .004 6.00E+06

Aulacoseira ambigua 12 .048 7.20E+07

Aulacoseira italica 8 .032 4.80E+07

Cocconeis placentula var. lineata 5 .020 3.00E+07

Cyclotella glomerata 1 .004 6.00E+06

Cyclotella michiganiana 3 .012 1.80E+07

Cyclotella stelligera 1 .004 6.00E+06

Cymbella angustata 4 .016 2.40E+07

Cymbella cistula 1 .004 6.00E+06

Cymbella sp. 3 .012 1.80E+07

Encyonema minutum 3 .012 1.80E+07

Encyonema silesiacum 5 .020 3.00E+07

Epithemia turgida 1 .004 6.00E+06

Eunotia arcus 3 .012 1.80E+07

Eunotia incisa 2 .008 1.20E+07

Eunotia sp. 1 .004 6.00E+06

Fragilaria capucina + vars. 3 .012 1.80E+07

Fragilaria crotonensis 4 .016 2.40E+07

Geissleria ignota v. palustris 1 .004 6.00E+06

Gomphonema (GV) 6 .024 3.60E+07

Gomphonema acuminatum 2 .008 1.20E+07

Gomphonema affine v. insigne 3 .012 1.80E+07

Gomphonema angustata 2 .008 1.20E+07

Gomphonema clevei 4 .016 2.40E+07

Gomphonema gracile 3 .012 1.80E+07

Gomphonema tenellum 2 .008 1.20E+07

Gomphonema truncatum 2 .008 1.20E+07

Gomphonema sp. 3 .012 1.80E+07

Navicula biconica 2 .008 1.20E+07

Navicula cryptotenella 4 .016 2.40E+07

Navicula minima 19 .076 1.14E+08

Navicula obdurata 1 .004 6.00E+06

Navicula pseudoventralis 7 .028 4.20E+07

Navicula radiosa 1 .004 6.00E+06

Navicula radiosafallax 2 .008 1.20E+07

Navicula sp. 2 .008 1.20E+07

Nitzschia amphibia 2 .008 1.20E+07

Nitzschia fonticola 1 .004 6.00E+06

Nitzschia palea 1 .004 6.00E+06

Nitzschia sp. 1 .004 6.00E+06

Pseudostaurosira brevistrata + vars. 2 .008 1.20E+07

Sellaphora rectangularis 6 .024 3.60E+07

Stauroneis acuta var. terryana 1 .004 6.00E+06

Stauroneis sp. 1 .004 6.00E+06

Staurosira construens 2 .008 1.20E+07

Staurosira construens var. venter 43 .172 2.58E+08

Staurosirella pinnata 9 .036 5.40E+07

Staurosirella pinnata v. lancettula 4 .016 2.40E+07

Synedra radians 1 .004 6.00E+06

Synedra rumpens var. familaris 5 .020 3.00E+07

Synedra ulna 1 .004 6.00E+06

Tabellaria sp. 2 .008 1.20E+07

Unknown (raphid) 1 .004 6.00E+06

Unknown 1 .004 6.00E+06

Total 250 1.000 1.50E+09

Chrysophyte cysts 2 1.20E+07
Table A8 121

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 60–62 cm

Achnanthidium exiguum var. heterovalvum 7 0.028 1.41E+07

Achnanthidium minutissima + vars. 28 .111 5.62E+07

Brachysira vitrea 1 .004 2.01E+06

Aulacoseira ambigua 19 .076 3.82E+07

Aulacoseira italica 10 .040 2.01E+07

Cocconeis placentula var. euglypta 2 .008 4.02E+06

Cocconeis placentula var. lineata 8 .032 1.61E+07

Craticola cuspidata 1 .004 2.01E+06

Cyclotella bodanica var. lemanica 1 .004 2.01E+06

Cyclotella glomerata 2 .008 4.02E+06

Cyclotella michiganiana 1 .004 2.01E+06

Cyclotella sp. 1 .004 2.01E+06

Cyclotella stelligera 1 .004 2.01E+06

Cymbella angustata 5 .020 1.00E+07

Cymbella cesatii 1 .004 2.01E+06

Cymbella cistula 2 .008 4.02E+06

Cymbella sp. 2 .008 4.02E+06

Encyonema minutum 2 .008 4.02E+06

Epithemia arcus 3 .012 6.03E+06

Epithemia turgida 2 .008 4.02E+06

Eunotia arcus 1 .004 2.01E+06

Eunotia incisa 9 .036 1.81E+07

Eunotia sp. 2 .008 4.02E+06

Fragilaria capucina + vars. 2 .008 4.02E+06

Fragilaria crotonensis 4 .016 8.03E+06

Fragilaria sp (65u L) 6 .024 1.21E+07

Fragilaria vaucheriae 4 .016 8.03E+06

Fragilaria sp. 2 .008 4.02E+06

Gomphonema acuminatum 6 .024 1.21E+07

Gomphonema affine var. insigne 4 .016 8.03E+06

Gomphonema angustata 7 .028 1.41E+07

Gomphonema clevei 4 .016 8.03E+06

Gomphonema intricatum 1 .004 2.01E+06

Gomphonema truncatum 2 .008 4.02E+06

Gomphonema truncatum v. turgidum 1 .004 2.01E+06

Gomphonema (GV) 8 .032 1.61E+07

Navicula atomus var. permitis 1 .004 2.01E+06

Navicula cryptotenella 2 .008 4.02E+06

Navicula laevissima 1 .004 2.01E+06

Navicula minima 2 .008 4.02E+06

Navicula obdurata 1 .004 2.01E+06

Navicula pseudoventralis 5 .020 1.00E+07

Navicula radiosa 2 .008 4.02E+06

Navicula radiosafallax 1 .004 2.01E+06

Navicula secura 4 .016 8.03E+06

Navicula sp. 2 .008 4.02E+06

Neidium sp. 1 .004 2.01E+06

Nitzschia amphibia 3 .012 6.03E+06

Nitzschia palea 2 .008 4.02E+06

Nitzschia sp. 4 .016 8.03E+06

Pinnularia sp. 1 .004 2.01E+06

Sellaphora pupula 2 .008 4.02E+06

Staurosira construens 5 .020 1.00E+07

Staurosira construens var. venter 28 .111 5.62E+07

Staurosirella pinnata 8 .032 1.61E+07

Surirella sp. 1 .004 2.01E+06

Synedra delicatissima 2 .008 4.02E+06

Synedra rumpens var. fragilariodes 2 .008 4.02E+06

Synedra rumpens var. familaris 1 .004 2.01E+06

Synedra ulna 2 .008 4.02E+06

Tabellaria sp. 4.5 .018 9.04E+06

Unknown (raphid) 2 .008 4.02E+06

Total 251.5 1.000 5.05E+08

Chrysophyte scales 1 2.01E+06
122 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 64–66 cm

Achnanthidium exiguum var. heterovalvum 15 0.060 6.36E+07

Achnanthidium minutissima + vars. 47 .187 1.99E+08

Achnanthidium sp. 1 .004 4.24E+06

Aulacoseira ambigua 11 .044 4.66E+07

Cocconeis placentula var. euglypta 1 .004 4.24E+06

Cocconeis placentula var. lineata 4 .016 1.70E+07

Cyclotella michiganiana 2 .008 8.48E+06

Cyclotella stelligera 3 .012 1.27E+07

Cymbella angustata 2 .008 8.48E+06

Cymbella cesatii 2 .008 8.48E+06

Cymbella cistula 3 .012 1.27E+07

Cymbella sp. 1 .004 4.24E+06

Encyonema minutum 2 .008 8.48E+06

Encyonema silesiacum 4 .016 1.70E+07

Epithemia arcus 1 .004 4.24E+06

Eunotia incisa 3 .012 1.27E+07

Eunotia pectinalis 1 .004 4.24E+06

Eunotia sp. 2 .008 8.48E+06

Fragilaria capucina + vars. 3 .012 1.27E+07

Fragilaria crotonensis 6 .024 2.54E+07

Fragilaria radians 1 .004 4.24E+06

Fragilaria vaucheriae 1 .004 4.24E+06

Geissleria ignota var. palustris 2 .008 8.48E+06

Gomphonema acuminatum 5 .020 2.12E+07

Gomphonema affine var. insigne 2 .008 8.48E+06

Gomphonema angustata 3 .012 1.27E+07

Gomphonema gracile 3 .012 1.27E+07

Gomphonema intricatum 1 .004 4.24E+06

Gomphonema subclavatum var. commutatum 1 .004 4.24E+06

Gomphonema tenellum 1 .004 4.24E+06

Gomphonema truncatum 2 .008 8.48E+06

Gomphonema (GV) 8 .032 3.39E+07

Gomphonema sp. 1 .004 4.24E+06

Navicula cryptotenella 3 .012 1.27E+07

Navicula glomus 1 .004 4.24E+06

Navicula graciloides 2 .008 8.48E+06

Navicula laterostrata 1 .004 4.24E+06

Navicula minima 17 .067 7.21E+07

Navicula pseudoventralis 9 .036 3.81E+07

Navicula radiosa 2 .008 8.48E+06

Navicula sp. 4 .016 1.70E+07

Neidium iridis 1 .004 4.24E+06

Nitzschia amphibia 4 .016 1.70E+07

Nitzschia palea 2 .008 8.48E+06

Nitzschia sp. 1 .004 4.24E+06

Pseudostaurosira brevistrata + vars. 2 .008 8.48E+06

Staurosira construens 6 .024 2.54E+07

Staurosira construens var. venter 28 .111 1.19E+08

Staurosirella leptostauron 1 .004 4.24E+06

Staurosirella pinnata 14 .056 5.93E+07

Staurosirella pinnata var. lancettula 1 .004 4.24E+06

Surirella sp. 1 .004 4.24E+06

Synedra rumpens var. familaris 1 .004 4.24E+06

Synedra rumpens var. fragilariodes 1 .004 4.24E+06

Synedra ulna 1 .004 4.24E+06

Tabellaria sp. 2 .008 8.48E+06

Unknown (raphid) 2 .008 8.48E+06

Total 252 1.000 1.07E+09

Chrysophyte scales 1 4.24E+06

Chrysophyte cysts 1 4.24E+06
Table A8 123

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in 

all counts, therefore the concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

MB-3, 70–72 cm

Achnanthidium exiguum var. heterovalvum 6 0.024 2.27E+07

Achnanthidium minutissima + vars. 27 .108 1.02E+08

Achnanthidium sp. 5 .020 1.89E+07

Asterionella formosa .5 .002 1.89E+06

Aulacoseira ambigua 4 .016 1.51E+07

Cocconeis placentula var. euglypta 1 .004 3.79E+06

Cocconeis placentula var. lineata 4 .016 1.51E+07

Craticola cuspidata 1 .004 3.79E+06

Cyclotella bodanica var. lemanica 1 .004 3.79E+06

Cyclotella sp. 1 .004 3.79E+06

Cymbella angustata 11 .044 4.17E+07

Cymbella cesatii 3 .012 1.14E+07

Cymbella cistula 4 .016 1.51E+07

Cymbella sp. 3 .012 1.14E+07

Encyonema minutum 4 .016 1.51E+07

Encyonema silesiacum 4 .016 1.51E+07

Epithemia sp. 2 .008 7.57E+06

Eunotia arcus 1 .004 3.79E+06

Eunotia incisa 3 .012 1.14E+07

Eunotia pectinalis 1 .004 3.79E+06

Fragilaria capucina + vars. 3 .012 1.14E+07

Fragilaria crotonensis 5 .020 1.89E+07

Fragilaria leptostauron 1 .004 3.79E+06

Fragilaria radians 1 .004 3.79E+06

Fragilaria vaucheriae 2 .008 7.57E+06

Geissleria ignota var. palustris 3 .012 1.14E+07

Gomphonema acuminatum 2 .008 7.57E+06

Gomphonema acuminatum var. pusilla 1 .004 3.79E+06

Gomphonema affine var. insigne 2 .008 7.57E+06

Gomphonema angustata 5 .020 1.89E+07

Gomphonema clevei 4 .016 1.51E+07

Gomphonema gracile 2 .008 7.57E+06

Gomphonema tenellum 3 .012 1.14E+07

Gomphonema (GV) 22 .088 8.33E+07

Gomphonema sp. 6 .024 2.27E+07

Navicula aurora 1 .004 3.79E+06

Navicula cryptotenella 8 .032 3.03E+07

Navicula laterostrata 2 .008 7.57E+06

Navicula minima 22 .088 8.33E+07

Navicula pseudoventralis 2 .008 7.57E+06

Navicula radiosa 3 .012 1.14E+07

Navicula sp. 2 .008 7.57E+06

Nitzschia amphibia 2 .008 7.57E+06

Nitzschia sp. 1 .004 3.79E+06

Pinnularia mesolepta 1 .004 3.79E+06

Pseudostaurosira brevistrata + vars. 2 .008 7.57E+06

Sellaphora pupula 1 .004 3.79E+06

Staurosira construens 1 .004 3.79E+06

Staurosira construens var. pumilla 3 .012 1.14E+07

Staurosira construens var. venter 21 .084 7.95E+07

Staurosirella pinnata 22 .088 8.33E+07

Staurosirella pinnata var. lancettula 3 .012 1.14E+07

Synedra rumpens var. fragilariodes 1 .004 3.79E+06

Synedra sp. 1 .004 3.79E+06

Synedra ulna 2 .008 7.57E+06

Synedra ulna var. chaseana 1 .004 3.79E+06

Unknown (raphid) 1 .004 3.79E+06

Total 250.5 1.000 9.53E+08

Chrysophyte cysts 2 0.008 7.57E+06
124 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Number 2 Proportion

Number/g 

dry 

sediment

LCO-1, 0–1 cm

Achnanthidium exiguum 3 0 0.017 1.97E+07

Achnanthidium lewisiana 1 1 .012 1.31E+07

Achnanthidium minutissima + vars. 2 1 .017 1.97E+07

Achnanthidium sp. 2 2 .023 2.63E+07

Asterionella formosa 3 0 .017 1.97E+07

Aulacoseira ambigua 5 2 .040 4.60E+07

Aulacoseira italica 0 1 .006 6.57E+06

Aulacoseira subarctica 0 3 .017 1.97E+07

Cavinula cocconeiformis 2 1 .017 1.97E+07

Cocconeis placentula var. lineata 1 0 .006 6.57E+06

Cocconeis neothumensis 2 0 .012 1.31E+07

Cyclotella sp. 1 3 0 .017 1.97E+07

Cyclotella comensis 14 8 .127 1.45E+08

Cyclotella michiganiana 3 0 .017 1.97E+07

Cyclotella planctonica 1 0 .006 6.57E+06

Cyclotella sp. 3 0 .017 1.97E+07

Cymbella cistula 2 0 .012 1.31E+07

Encyonema silesiacum 1 0 .006 6.57E+06

Epithemia turgida 1 0 .006 6.57E+06

Epithemia sp. 2 0 .012 1.31E+07

Eunotia flexuosa 0 1 .006 6.57E+06

Eunotia sp. .5 0 .003 3.28E+06

Fragilaria capucina + vars. 4 0 .023 2.63E+07

Fragilaria vaucheriae 1 0 .006 6.57E+06

Geissleria ignota var. palustris 1 0 .006 6.57E+06

Gomphonema parvulum fo. micropus 0 1 .006 6.57E+06

Gomphonema pseudotenellum 1 0 .006 6.57E+06

Gomphonema sp. 1 0 .006 6.57E+06

Navicula minima 1 1 .012 1.31E+07

Navicula pseudoventralis 2 0 .012 1.31E+07

Navicula radiofallax 2 0 .012 1.31E+07

Navicula (GV) 2 0 .012 1.31E+07

Navicula sp. 1 1 .012 1.31E+07

Nitzschia sp. 2 0 .012 1.31E+07

Pinnularia abaujensis var. linearis 1 0 .006 6.57E+06

Pinnularia sp. 1 1 .012 1.31E+07

Planothidium lanceolata 4 1 .029 3.28E+07

Pseudostaurosira brevistrata + vars. 5 1 .035 3.94E+07

Rhizosolenia erensis .5 0 .003 3.28E+06

Sellaphora rectangularis 1 0 .006 6.57E+06

Staurosira construens 0 16 .092 1.05E+08

Staurosira construens var. venter 17 3 .116 1.31E+08

Staurosira lapponica 2 2 .023 2.63E+07

Staurosirella pinnata 10 4 .081 9.20E+07

Synedra rumpens var. familaris 1 0 .006 6.57E+06

Synedra sp. 1 0 .006 6.57E+06

Tabellaria flocculosa str. IIIp 3 0 .017 1.97E+07

Tabellaria quadrasepta 0 1 .006 6.57E+06

Unknown (raphid) 2 0 .012 1.31E+07

Unknown 3 0 .017 1.97E+07

TOTAL 121 52 1.000 1.14E+09

Chrysophyte cysts 1 2

Scenedesmus coenobia 5 1

Tetraedron coenobia 1 0
Table A8 125

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

LCO-1, 10–11 cm

Achnanthidium minutissima + vars. 4 0.025 6.13E+07

Aulacoseira ambigua 1 .006 1.53E+07

Aulacoseira granulata 1 .006 1.53E+07

Aulacoseira italica 2 .012 3.06E+07

Aulacoseira subarctica 2 .012 3.06E+07

Aulacoseira VV 1 .006 1.53E+07

Cyclotella sp1 1 .006 1.53E+07

Cyclotella comensis 7 .043 1.07E+08

Diploneis elliptica 1 .006 1.53E+07

Cyclotella bodanica var. lemanica 2 .012 3.06E+07

Cyclotella glomerata 1 .006 1.53E+07

Cyclotella michiganiana 3 .019 4.60E+07

Cymbella angustata 2 .012 3.06E+07

Eucocconeis flexella 1 .006 1.53E+07

Epithemia adnata 1 .006 1.53E+07

Epithemia turgida 1 .006 1.53E+07

Eunotia incisa 1 .006 1.53E+07

Fragilaria capucina + vars. 5 .031 7.66E+07

Fragilaria crotonensis 6 .037 9.19E+07

Fragilaria vaucheriae 1 .006 1.53E+07

Fragilaria cf. nitzschioides 1 .006 1.53E+07

Geissleria ignota var. palustris 3 .019 4.60E+07

Gomphonema pseudotenellum 1 .006 1.53E+07

Navicula atomus var. permitis 2 .012 3.06E+07

Navicula lanceolata 3 .019 4.60E+07

Navicula minima 5 .031 7.66E+07

Navicula pseudoventralis 4 .025 6.13E+07

Navicula seminuloides 1 .006 1.53E+07

Navicula tripunctata 3 .019 4.60E+07

Navicula sp1 LCO 2 .012 3.06E+07

Navicula (GV) 4 .025 6.13E+07

Navicula sp. 2 .012 3.06E+07

Nitzschia sp. 1 .006 1.53E+07

Planothidium lanceolata 3 .019 4.60E+07

Pseudostaurosira brevistrata + vars. 16 .099 2.45E+08

Rhopalodia gibba 1 .006 1.53E+07

Staurosira construens 6 .037 9.19E+07

Staurosira construens var. venter 28 .174 4.29E+08

Staurosira elliptica 5 .031 7.66E+07

Staurosirella pinnata 18 .112 2.76E+08

Synedra rumpens 1 .006 1.53E+07

Synedra (GV) 1 .006 1.53E+07

Synedra sp. 1 .006 1.53E+07

Tabellaria flocculosa str. IIIp 1 .006 1.53E+07

Unknown (raphid) 3 .019 4.60E+07

Unknown 1 .006 1.53E+07

TOTAL 161 1.000 2.47E+09

Scenedesmus coenobia 2
126 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

LCO-1, 16–17 cm

Achnanthidium exiguum 1 0.006 6.14E+06

Achnanthidium stewartii 1 .006 6.14E+06

Achnanthidium suchlandtii 1 .006 6.14E+06

Achnanthidium minutissima + vars. 1 .006 6.14E+06

Amphora perpusilla 2 .012 1.23E+07

Aulacoseira ambigua 6 .037 3.68E+07

Aulacoseira subarctica 1 .006 6.14E+06

Cavinula cocconeiformis 1 .006 6.14E+06

Cyclotella bodanica var. lemanica 2 .012 1.23E+07

Cymatosira robusta 1 .006 6.14E+06

Cymbella angustata 1 .006 6.14E+06

Epithemia turgida 1 .006 6.14E+06

Fragilaria crotonensis 3 .018 1.84E+07

Fragilaria oldenburgiana 1 .006 6.14E+06

Fragilaria vaucheriae 1 .006 6.14E+06

Geissleria ignota var. palustris 1 .006 6.14E+06

Geissleria schoenfeldii 1 .006 6.14E+06

Karayevia clevei 1 .006 6.14E+06

Martyi martyi 1 .006 6.14E+06

Navicula atomus var. permitis 1 .006 6.14E+06

Navicula minima 3 .018 1.84E+07

Navicula pseudoventralis 4 .025 2.46E+07

Navicula schadei 1 .006 6.14E+06

Navicula seminuloides 4 .025 2.46E+07

Navicula ventralis 1 .006 6.14E+06

Navicula tripunctata 1 .006 6.14E+06

Navicula sp. 2 .012 1.23E+07

Nitzschia amphibia 2 .012 1.23E+07

Nitzschia sp. 2 .012 1.23E+07

Pinnularia sp. 1 .006 6.14E+06

Pseudostaurosira brevistrata + vars. 14 .086 8.60E+07

Stauroneis sp. 1 .006 6.14E+06

Staurosira construens 9 .055 5.53E+07

Staurosira construens var. binodis 5 .031 3.07E+07

Staurosira construens var. venter 22 .135 1.35E+08

Staurosira elliptica 32 .196 1.96E+08

Staurosirella pinnata 24 .147 1.47E+08

Stephanodiscus minutulus 1 .006 6.14E+06

Synedra rumpens 2 .012 1.23E+07

Synedra rumpens var. familaris 1 .006 6.14E+06

Unknown (raphid) 2 .012 1.23E+07

Unknown 0 .000 0.00E+00

TOTAL 163 1.000 1.00E+09

Chrysophyte scales 1

Chrysophyte cysts 1

Scenedesmus coenobia 6
Table A8 127

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

LCO-1, 24–25 cm

Achnanthidium exiguum 2 0.012 9.71E+06

Achnanthidium stewartii 5 .030 2.43E+07

Achnanthidium suchlandtii 5 .030 2.43E+07

Amphora perpusilla 1 .006 4.86E+06

Aulacoseira ambigua 5 .030 2.43E+07

Aulacoseira distans 1 .006 4.86E+06

Aulacoseira subarctica 1 .006 4.86E+06

Aulacoseira (VV) 3 .018 1.46E+07

Cocconeis placentula var. lineata 1 .006 4.86E+06

Cocconeis placentula (RV) 4 .024 1.94E+07

Cyclotella michiganiana 4 .024 1.94E+07

Cyclotella sp. 1 .006 4.86E+06

Cymbella cistula 1 .006 4.86E+06

Epithemia adnata 1 .006 4.86E+06

Epithemia sp. 1 .006 4.86E+06

Fragilaria oldenburgiana 1 .006 4.86E+06

Fragilaria vaucheriae 2 .012 9.71E+06

Geissleria ignota var. palustris 3 .018 1.46E+07

Geissleria schoenfeldii 1 .006 4.86E+06

Gomphonema acuminatum 1 .006 4.86E+06

Gomphonema subclavatum var. commutatum 2 .012 9.71E+06

Gomphonema pseudotenellum 1 .006 4.86E+06

Gomphonema sp. 2 .012 9.71E+06

Martyi martyi 4 .024 1.94E+07

Navicula cocconeiformis 2 .012 9.71E+06

Navicula lanceolata 1 .006 4.86E+06

Navicula pseudoventralis 4 .024 1.94E+07

Navicula seminuloides 2 .012 9.71E+06

Navicula tripunctata 4 .024 1.94E+07

Navicula sp. 4 .024 1.94E+07

Neidium sp. 1 .006 4.86E+06

Pinnularia sp. 2 .012 9.71E+06

Planothidium lanceolata var. dubia 2 .012 9.71E+06

Pseudostaurosira brevistrata + vars. 13 .078 6.31E+07

Staurosira construens 10 .060 4.86E+07

Staurosira construens var. venter 20 .120 9.71E+07

Staurosira elliptica 18 .108 8.74E+07

Staurosirella pinnata 26 .156 1.26E+08

Stephanodiscus minutulus 1 .006 4.86E+06

Stephanodiscus medius 1 .006 4.86E+06

Tabellaria flocculosa str. IIIp 1 .006 4.86E+06

Unknown (raphid) 1 .006 4.86E+06

Unknown 1 .006 4.86E+06

TOTAL 167 1.000 8.11E+08

Chrysophyte cysts 2

Scenedesmus coenobia 3
128 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A8. Results from analysis of diatom assemblages from Musky Bay MB-1 and MB-3 cores and 

Northeastern Bay LCO-1 core, Lac Courte Oreilles, October 1999—Continued

[cm, centimeter; g, gram; Concentration (Number/g dry sediment) was not determined in all counts, therefore the 

concentration value may be zero.]

Taxa Number 1 Proportion

Number/g 

dry 

sediment

LCO-1, 40–41 cm

Achnanthidium exiguum 8 0.050 3.84E+07

Achnanthidium stewartii 3 .019 1.44E+07

Achnanthidium suchlandtii 1 .006 4.81E+06

Achnanthidium (GV) 1 .006 4.81E+06

Amphora ovalis var. affinis 3 .019 1.44E+07

Amphora perpusilla 5 .031 2.40E+07

Aulacoseira ambigua 16 .100 7.69E+07

Aulacoseira distans 1 .006 4.81E+06

Aulacoseira subarctica 2 .013 9.61E+06

Cyclotella bodanica var. lemanica 2 .013 9.61E+06

Cyclotella ocellata 1 .006 4.81E+06

Cymbella cuspidata 1 .006 4.81E+06

Fragilaria oldenburgiana 2 .013 9.61E+06

Geissleria ignota var. palustris 2 .013 9.61E+06

Geissleria schoenfeldii 5 .031 2.40E+07

Gomphonema subclavatum var. commutatum 1 .006 4.81E+06

Gomphonema pseudotenellum 1 .006 4.81E+06

Gomphonema sp. 1 .006 4.81E+06

Martyi martyi 1 .006 4.81E+06

Navicula atomus var. permitis 3 .019 1.44E+07

Navicula lanceolata 1 .006 4.81E+06

Navicula minima 2 .013 9.61E+06

Navicula pseudoventralis 3 .019 1.44E+07

Navicula seminuloides 3 .019 1.44E+07

Navicula tripunctata 7 .044 3.36E+07

Navicula sp. 6 .038 2.88E+07

Nitzschia amphibia 2 .013 9.61E+06

Nitzschia sp. 2 .013 9.61E+06

Pinnularia sp. 1 .006 4.81E+06

Planothidium lanceolata 3 .019 1.44E+07

Planothidium lanceolata var. dubia 1 .006 4.81E+06

Pseudostaurosira brevistrata + vars. 14 .088 6.73E+07

Sellaphora seminulum 1 .006 4.81E+06

Staurosira construens 7 .044 3.36E+07

Staurosira construens var. venter 14 .088 6.73E+07

Staurosira elliptica 15 .094 7.21E+07

Staurosirella pinnata 12 .075 5.77E+07

Staurosirella pinnata var. intercedens 3 .019 1.44E+07

Staurosira contruens var. subsalina 2 .013 9.61E+06

Thalassiosira sp. 1 .006 4.81E+06

Unknown (raphid) 0 .000 0.00E+00

Unknown 0 .000 0.00E+00

TOTAL 160 1.000 7.69E+08

Chrysophyte cysts 4

Scenedesmus coenobia 2
Table A9 129

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999

[cm, centimeter]

Number Proportion

2–4 cm

Terrestrial Pollen

Acer 24 0.076

Celtis 3 .010

Cornus 1 .003

Corylus 3 .010

Larix 1 .003

Betula 40 .127

Alnus 9 .029

Quercus 28 .089

Populus 3 .010

Abies 5.5 .017

Pinus 124.5 .395

Ostrya 5 .016

Tilia 3 .010

Ulmus 1 .003

Thalictrum 2 .006

Ambrosia 27 .086

Carophyllaceae 3 .010

Plantago 1 .003

Grass 14 .044

Unknown 17 .054

TOTAL 315 1.000

Aquatic Pollen

Typha 16 .051

Myriophyllum 5 .016

Potamogeton, reticulated 11 .035

Potamogeton, smooth 7 .022

Heterantera dubia 3 .010

Utricularia 5 .016

Nymphaea 2 .006

Coelastrum coenobia 3 .010

Tetraedron coenobia 1 .003

Pediastrum coenobia 23 .073

Scenedesmus coenobia 39 .124

Zooplankton parts 21

Chironomid mental plate 1

10–12 cm

Terrestrial Pollen

Larix 2 0.017

Betula 19 .164

Alnus 9 .078

Quercus 18 .155

Abies 1.5 .013

Pinus 42.5 .366

Ostrya 7 .060

Tsuga 1 .009

Ambrosia 2 .017

Artemsia 2 .017

Chenopodiaceae 2 .017

Pteridium 1 .009

Grass 6 .052

Unknown 3 .026

TOTAL 116 1.000

Aquatic Pollen

Zizania palustris 1 .009

Typha 1 .009

Myriophyllum 4 .034

Potamogeton, reticulated 1 .009

Heterantera dubia 1 .009

Utricularia 1 .009

Ceratophyllum spine 1 .009

Coelastrum coenobia 1 .009

Tetraedron coenobia 1 .009

Pediastrum coenobia 5 .043

Scenedesmus coenobia 8 .063

Zooplankton parts 2

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion
130 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

20–22 cm

Terrestrial Pollen

Celtis 2 0.020

Larix 1 .010

Betula 18 .176

Alnus 1 .010

Quercus 5 .049

Abies 4 .039

Pinus 53 .520

Ostrya 6 .059

Tilia 1 .010

Tsuga 1 .010

Ambrosia 5 .049

Carophyllaceae 1 .010

Dryopteris 1 .010

Chenopodiaceae 1 .010

Unknown 2 .020

TOTAL 102 1.000

Aquatic Pollen

Zizania palustris

Typha 1 .010

Myriophyllum 2 .020

Potamogeton, reticulated 5 .049

Utricularia 3 .029

Coelastrum coenobia 1 .010

Pediastrum coenobia 4 .039

Scenedesmus coenobia 6 .059

Zooplankton parts 2

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion

30–32 cm

Terrestrial Pollen

Celtis 3 0.029

Juniperus or Thuja 2 .020

Larix 1 .010

Betula 14 .137

Alnus 7 .069

Quercus 11 .108

Abies 5 .049

Pinus 45 .441

Ostrya 5 .049

Tilia 4 .039

Ambrosia 2 .020

Artemsia 1 .010

Pteridium 1 .010

Unknown 1 .010

TOTAL 102 1.000

Aquatic Pollen

Zizania palustris 1 .010

Typha 5 .049

Myriophyllum 2 .020

Potamogeton, reticulated 2 .020

Utricularia 1 .010

Coelastrum coenobia 1 .010

Tetraedron coenobia 1 .010

Pediastrum coenobia 8 .078

Scenedesmus coenobia 6 .059

Zooplankton parts 2

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion
Table A9 131

40–42 cm

Terrestrial Pollen

Acer 1 0.010

Celtis 2 .020

Betula 12 .118

Alnus 1 .010

Quercus 8 .078

Abies 1.5 .015

Pinus 60.5 .593

Ostrya 1 .010

Salix 1 .010

Tsuga 3 .029

Ambrosia 2 .020

Artemsia 3 .029

Chenopodiaceae 2 .020

Pteridium 2 .020

Unknown 2 .020

TOTAL 102 1.000

Aquatic Pollen

Zizania palustris 1 .010

Myriophyllum 2 .020

Potamogeton, smooth 1 .010

Utricularia 1 .010

Lemna 1 .010

Sphagnum 1 .010

Coelastrum coenobia 1 .010

Tetraedron coenobia 1 .010

Pediastrum coenobia 1 .010

Scenedesmus coenobia 2 .020

Staurastrum coenobia 1 .010

Zooplankton parts 1

Chironomid mental plate 1

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion

50–52 cm

Terrestrial Pollen

Acer 24 0.080

Celtis 3 .010

Cornus 1 .003

Corylus 3 .010

Larix 1 .003

Betula 40 .133

Alnus 9 .030

Quercus 28 .093

Populus 3 .010

Abies 5.5 .018

Pinus 124.5 .414

Ostrya 5 .017

Tilia 3 .010

Ulmus 1 .003

Thalictrum 2 .007

Ambrosia 27 .090

Carophyllaceae 3 .010

Plantago 1 .003

Unknown 17 .056

TOTAL 301 1.000

Aquatic Pollen

Typha 16 .053

Myriophyllum 5 .017

Potamogeton, reticulated 11 .037

Potamogeton, smooth 7 .023

Heterantera dubia 3 .010

Utricularia 5 .017

Nymphaea 2 .007

Coelastrum coenobia 3 .010

Tetraedron coenobia 1 .003

Pediastrum coenobia 23 .076

Scenedesmus coenobia 39 .130

Zooplankton parts 21

Chironomid mental plate 1

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion
132 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

58–60 cm

Terrestrial Pollen

Juniperus or Thuja 1 0.007

Betula 18 .119

Alnus 2 .013

Quercus 7 .046

Abies 7 .046

Pinus 77 .510

Ostrya 6 .040

Tilia 2 .013

Ulmus 2 .013

Tubuliflorae 1 .007

Iva 1 .007

Ambrosia 13 .086

Osmunda 1 .007

Urtica 2 .013

Artemsia 1 .007

Chenopodiaceae 1 .007

Plantago 1 .007

Pteridium 2 .013

Grass 4 .026

Unknown 2 .013

TOTAL 151 1.000

Aquatic Pollen

Zizania palustris 27 .179

Typha 4 .026

Isoetes 1 .007

Myriophyllum 1 .007

Potamogeton, reticulated 2 .013

Heterantera dubia 4 .026

Utricularia 4 .026

Coelastrum coenobia 1 .007

Pediastrum coenobia 10 .066

Zooplankton parts 2

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion

70–72 cm

Terrestrial Pollen

Acer 1 0.006

Corylus 1 .006

Betula 29.5 .177

Alnus 5 .030

Quercus 19 .114

Abies 11 .066

Pinus 69 .414

Ostrya 7 .042

Tilia 1 .006

Ulmus 1 .006

Tubuliflorae 2 .012

Iva 7 .042

Ambrosia 4 .024

Urtica 3 .018

Artemsia 2 .012

Chenopodiaceae 1 .006

Pteridium 1 .006

Grass 1 .006

Unknown 1 .006

TOTAL 166.5 1.000

Aquatic Pollen

Zizania palustris 26 .156

Typha 4 .024

Myriophyllum 1 .006

Potamogeton, reticulated 8 .048

Utricularia 3 .018

Tetraedron coenobia 1 .006

Pediastrum coenobia 13 .078

Zooplankton parts 3

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion
Table A9 133

80–82 cm

Terrestrial Pollen

Corylus 3 0.020

Betula 24 .163

Alnus 1 .007

Quercus 15 .102

Abies 9 .061

Pinus 74 .503

Ostrya 9 .061

Ulmus 2 .014

Iva 2 .014

Ambrosia 2 .014

Chenopodiaceae 1 .007

Pteridium 1 .007

Heterantheria dubia 2 .014

Grass 2 .014

TOTAL 147 1.000

Aquatic Pollen

Zizania palustris 10 .068

Typha 4 .027

Utricularia 4 .027

Coelastrum coenobia 2 .014

Pediastrum coenobia 9 .061

Zooplankton parts 1

Table A9. Results from analysis of pollen assemblages 

from Musky Bay core MB-3, Lac Courte Oreilles, October 

1999—Continued

[cm, centimeter]

Number Proportion
134 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Table A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and

surrounding areas, October 1999 and July 2001

[cm, centimeter; %, percent; wt, weight; na, no data]

Field no. Interval 

(cm) Type of data Replicate 1 Replicate 2 Absolute difference

Percent 

error

Average

percent error

MB-1-19 18–19 Water weight (%) 97.1 97.3 0.2 0.2 4.4

MB-1-39 38–39 Water weight (%) 96.3 96.1 .2 .2

MB-1-59 66–68 Water weight (%) 96.1 96 .1 .1

MB-1-65 78–80 Water weight. (%) 94.2 94.1 .1 .1

JON-1-1 0–10 Water weight (%) 51.7 43 8.7 18.4

ZAW-1-1 0–8 Water weight (%) 21.3 19.8 1.5 7.3

MB-1-19 18–19 Organic content (%) 48.6 47.5 1.1 2.3 8.7

MB-1-39 38–39 Organic content (%) 46.4 46.7 .3 .6

MB-1-59 66–68 Organic content (%) 56.4 56.4 .0 .0

MB-1-65 78–80 Organic content (%) 60.6 60.2 .4 .7

JON-1-1 0–10 Organic content (%) 16.5 11 5.5 40.0

LCO-1-13 12–13 Aluminum 1.8 1.8 .0 .0 11.7

LCO-1-23 22–23 Aluminum 1.8 1.7 .1 5.7

MB-1-34 33–34 Aluminum 1.1 .94 .16 15.7

MB-1-41 40–41 Aluminum .96 1.0 .04 4.1

MB-1-61 70–72 Aluminum .86 1.2 .34 33.0

LCO-1-13 12–13 Antimony .67 .7 .03 4.4 22.7

LCO-1-23 22–23 Antimony .29 .22 .07 27.5

MB-1-34 33–34 Antimony .48 .52 .04 8.0

MB-1-41 40–41 Antimony .49 .36 .13 30.6

MB-1-61 70–72 Antimony .31 .48 .17 43.0

LCO-1-13 12–13 Arsenic 15 15 .0 .0 4.6

LCO-1-23 22–23 Arsenic 5.7 6.5 .8 13.1

MB-1-34 33–34 Arsenic 5.8 6 .2 3.4

MB-1-41 40–41 Arsenic 6.4 6.6 .2 3.1

MB-1-61 70–72 Arsenic 6.1 5.9 .2 3.3

LCO-1-13 12–13 Barium 260 250 10 3.9 3.2

LCO-1-23 22–23 Barium 240 240 0 0

MB-1-34 33–34 Barium 150 150 0 0

MB-1-41 40–41 Barium 160 170 10 6.1

MB-1-61 70–72 Barium 170 160 10 6.1

LCO-1-13 12–13 Beryllium .46 .76 .3 49.2 33.8

LCO-1-23 22–23 Beryllium .53 .4 .13 28.0

MB-1-34 33–34 Beryllium .45 .43 .02 4.5

MB-1-41 40–41 Beryllium .46 .26 .2 55.6

MB-1-61 70–72 Beryllium .24 .33 .09 31.6

LCO-1-13 12–13 Cadmium 1.2 1.4 .2 15.4 13.3

LCO-1-23 22–23 Cadmium .26 .31 .05 17.5

MB-1-34 33–34 Cadmium 1.3 1.3 .0 .0

MB-1-41 40–41 Cadmium 1.3 1.1 .2 16.7

MB-1-61 70–72 Cadmium 1.1 1.3 .2 16.7
Table A10 135

LCO-1-13 12–13 Calcium .74 .72 .02 2.7 9.3

LCO-1-23 22–23 Calcium .63 .66 .03 4.7

MB-1-34 33–34 Calcium .64 .59 .05 8.1

MB-1-41 40–41 Calcium .63 .78 .15 21.3

MB-1-61 70–72 Calcium .67 .74 .07 9.9

LCO-1-13 12–13 Cerium 30 29 1 3.4 3.4

LCO-1-23 22–23 Cerium 26 26 0 0

MB-1-34 33–34 Cerium 15 15 0 0

MB-1-41 40–41 Cerium 15 14 1 6.9

MB-1-61 70–72 Cerium 14 15 1 6.9

LCO-1-13 12–13 Chromium 33 34 1 3.0 6.0

LCO-1-23 22–23 Chromium 28 28 0 0

MB-1-34 33–34 Chromium 17 17 0 0

MB-1-41 40–41 Chromium 16 13 3 20.7

MB-1-61 70–72 Chromium 15 16 1 6.5

LCO-1-13 12–13 Cobalt 7.5 7.5 0.0 0.0 10.4

LCO-1-23 22–23 Cobalt 4.8 5.4 .6 11.8

MB-1-34 33–34 Cobalt 3.2 3.1 .1 3.2

MB-1-41 40–41 Cobalt 3.0 2.4 .6 22.2

MB-1-61 70–72 Cobalt 2.5 2.9 .4 14.8

LCO-1-13 12–13 Copper 29 41 12 34.3 32.5

LCO-1-23 22–23 Copper 15 16 1 6.5

MB-1-34 33–34 Copper 35 26 9 29.5

MB-1-41 40–41 Copper 20 17 3 16.2

MB-1-61 70–72 Copper 13 29 16 76.2

LCO-1-13 12–13 Gallium 5.0 4.8 .2 4.1 7.3

LCO-1-23 22–23 Gallium 4.2 4.2 0.0 0.0

MB-1-34 33–34 Gallium 3.2 3.0 .2 6.5

MB-1-41 40–41 Gallium 2.9 2.5 .4 14.8

MB-1-61 70–72 Gallium 2.5 2.8 .3 11.3

LCO-1-13 12–13 Iron 2.6 2.8 .2 7.4 5.2

LCO-1-23 22–23 Iron .94 1.0 .06 6.2

MB-1-34 33–34 Iron .82 .80 .02 2.5

MB-1-41 40–41 Iron .81 .78 .03 3.8

MB-1-61 70–72 Iron .83 .78 .05 6.2

LCO-1-13 12–13 Lanthanum 14 14 0 0 6.3

LCO-1-23 22–23 Lanthanum 12 14 2 15.4

MB-1-34 33–34 Lanthanum 7.6 8.0 .4 5.1

MB-1-41 40–41 Lanthanum 7.7 7.3 .4 5.3

MB-1-61 70–72 Lanthanum 7.1 7.5 .4 5.5

LCO-1-13 12–13 Lead 67 68 1 1.5 17.7

LCO-1-23 22–23 Lead 8.0 8.5 .5 6.1

Table A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and

surrounding areas, October 1999 and July 2001—Continued

[cm, centimeter; %, percent; wt, weight; na, no data]

Field no. Interval 

(cm) Type of data Replicate 1 Replicate 2 Absolute 

difference

Percent 

error

Average

percent error
136 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

MB-1-34 33–34 Lead 42 41 1 2.4

MB-1-41 40–41 Lead 36 23 13 44.1

MB-1-61 70–72 Lead 24 34 10 34.5

LCO-1-13 12–13 Lithium 9.1 9.4 .3 3.2 6.8

LCO-1-23 22–23 Lithium 6.2 6.5 .3 4.7

MB-1-34 33–34 Lithium 6.1 5.8 .3 5.0

MB-1-41 40–41 Lithium 5.7 5.7 0.0 0.0

MB-1-61 70–72 Lithium 5.1 6.3 1.2 21.1

LCO-1-13 12–13 Magnesium .31 .31 .00 .0 11.1

LCO-1-23 22–23 Magnesium .26 .28 .02 7.4

MB-1-34 33–34 Magnesium .18 .16 .02 11.8

MB-1-41 40–41 Magnesium .17 .21 .04 21.1

MB-1-61 70–72 Magnesium .18 .21 .03 15.4

LCO-1-13 12–13 Manganese 1,500 1,600 100 6.5 8.5

LCO-1-23 22–23 Manganese 520 570 50 9.2

MB-1-34 33–34 Manganese 340 330 10 3.0

MB-1-41 40–41 Manganese 360 390 30 8.0

MB-1-61 70–72 Manganese 410 350 60 15.8

LCO-1-13 12–13 Molybdenum 1.1 1.1 0.0 0.0 7.8

LCO-1-23 22–23 Molybdenum .63 .68 .05 7.6

MB-1-34 33–34 Molybdenum .88 .97 .09 9.7

MB-1-41 40–41 Molybdenum .87 .92 .05 5.6

MB-1-61 70–72 Molybdenum .75 .88 .13 16.0

LCO-1-13 12–13 Neodymium 14 14 0 0 2.6

LCO-1-23 22–23 Neodymium 13 13 0 0

MB-1-34 33–34 Neodymium 7.1 7.1 0.0 0.0

MB-1-41 40–41 Neodymium 7.1 6.7 .4 5.8

MB-1-61 70–72 Neodymium 6.5 7.0 .5 7.4

LCO-1-13 12–13 Nickel 16 16 0 0 5.4

LCO-1-23 22–23 Nickel 12 12 0 0

MB-1-34 33–34 Nickel 9.2 8.9 .3 3.3

MB-1-41 40–41 Nickel 8.9 7.9 1 11.9

MB-1-61 70–72 Nickel 8.1 9.1 1 11.6

LCO-1-13 12–13 Niobium 4.6 4.6 0.0 0.0 1.8

LCO-1-23 22–23 Niobium 4.6 4.2 .4 9.1

MB-1-34 33–34 Niobium <4 <4 0 0

MB-1-41 40–41 Niobium <4 <4 0 0

MB-1-61 70–72 Niobium <4 <4 0 0

LCO-1-13 12–13 Phosphorus .084 .082 .002 2.4 13.2

LCO-1-23 22–23 Phosphorus .027 .030 .003 10.5

MB-1-34 33–34 Phosphorus .083 .075 .008 10.1

MB-1-41 40–41 Phosphorus .071 .085 .014 17.9

Table A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and

surrounding areas, October 1999 and July 2001—Continued

[cm, centimeter; %, percent; wt, weight; na, no data]

Field no. Interval 

(cm) Type of data Replicate 1 Replicate 2 Absolute 

difference

Percent 

error

Average

percent error
Table A10 137

MB-1-61 70–72 Phosphorus .067 .086 .019 24.8

LCO-1-13 12–13 Potassium .57 .52 .05 9.2 8.6

LCO-1-23 22–23 Potassium .86 .82 .04 4.8

MB-1-34 33–34 Potassium .29 .26 .03 10.9

MB-1-41 40–41 Potassium .28 .28 .00 .00

MB-1-61 70–72 Potassium .25 .30 .05 18.2

LCO-1-13 12–13 Scandium 5.5 5.3 .2 3.7 12.7

LCO-1-23 22–23 Scandium 4.5 4.6 .1 2.2

MB-1-34 33–34 Scandium 2.3 2.0 .3 14.0

MB-1-41 40–41 Scandium 2.1 2.5 .4 17.4

MB-1-61 70–72 Scandium 2.0 2.6 .6 26.1

LCO-1-13 12–13 Sodium .27 .25 .02 7.7 10.6

LCO-1-23 22–23 Sodium .39 .38 .01 2.6

MB-1-34 33–34 Sodium .11 .10 .01 9.5

MB-1-41 40–41 Sodium .11 .13 .02 16.7

MB-1-61 70–72 Sodium .11 .13 .02 16.7

LCO-1-13 12–13 Strontium 45 42 3 6.7 4.3

LCO-1-23 22–23 Strontium 55 54 1 1.8

MB-1-34 33–34 Strontium 33 33 0 0

MB-1-41 40–41 Strontium 33 30 3 9.5

MB-1-61 70–72 Strontium 32 31 1 3.2

LCO-1-13 12–13 Sulfur .60 .62 .02 3.3 9.8

LCO-1-23 22–23 Sulfur .21 .28 .07 28.6

MB-1-34 33–34 Sulfur .64 .64 0 0

MB-1-41 40–41 Sulfur .62 .56 .06 10.2

MB-1-61 70–72 Sulfur .57 .61 .04 6.8

LCO-1-13 12–13 Thorium 3.0 2.8 .2 6.9 6.5

LCO-1-23 22–23 Thorium 2.4 2.4 0 0

MB-1-34 33–34 Thorium 2.0 2.2 .2 9.5

MB-1-41 40–41 Thorium 2.0 1.8 .2 10.5

MB-1-61 70–72 Thorium 1.8 1.9 .1 5.4

LCO-1-13 12–13 Tin 2.1 2.0 .1 4.9 3.6

LCO-1-23 22–23 Tin <1.0 <1.0 0 0

MB-1-34 33–34 Tin 1.4 1.6 .2 13.3

MB-1-41 40–41 Tin 1.4 <1.0 na na

MB-1-61 70–72 Tin <1.0 1.0 na na

LCO-1-13 12–13 Titanium .13 .13 0 0 9.8

LCO-1-23 22–23 Titanium .15 .13 .02 14.3

MB-1-34 33–34 Titanium .052 .052 0 0

MB-1-41 40–41 Titanium .051 .057 .006 11.1

MB-1-61 70–72 Titanium .045 .057 .012 23.5

LCO-1-13 12–13 Uranium 1.5 1.5 0 0 4.7

Table A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and

surrounding areas, October 1999 and July 2001—Continued

[cm, centimeter; %, percent; wt, weight; na, no data]

Field no. Interval 

(cm) Type of data Replicate 1 Replicate 2 Absolute 

difference

Percent 

error

Average

percent error
138 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

LCO-1-23 22–23 Uranium 1.2 1.2 0 0

MB-1-34 33–34 Uranium .72 .74 .02 2.7

MB-1-41 40–41 Uranium .73 .63 .1 14.7

MB-1-61 70–72 Uranium .65 .69 .04 6.0

LCO-1-13 12–13 Vanadium 54 54 0 0 9.1

LCO-1-23 22–23 Vanadium 37 39 2 5.3

MB-1-34 33–34 Vanadium 22 22 0 0

MB-1-41 40–41 Vanadium 22 18 4 20.0

MB-1-61 70–72 Vanadium 18 22 4 20.0

LCO-1-13 12–13 Ytterbium 1.8 1.8 0 0 1.1

LCO-1-23 22–23 Ytterbium 1.9 1.8 .1 5.4

MB-1-34 33–34 Ytterbium <1.0 <1.0 0 0

MB-1-41 40–41 Ytterbium 1.0 <1.0 na na

MB-1-61 70–72 Ytterbium <1 <1.0 0 0

LCO-1-13 12–13 Yttrium 13 14 1 7.4 6.6

LCO-1-23 22–23 Yttrium 13 12 1 8.0

MB-1-34 33–34 Yttrium 5.7 6.0 .3 5.1

MB-1-41 40–41 Yttrium 5.8 5.4 .4 7.1

MB-1-61 70–72 Yttrium 5.5 5.8 .3 5.3

LCO-1-13 12–13 Zinc 110 130 20 16.7 16.1

LCO-1-23 22–23 Zinc 28 31 3 10.2

MB-1-34 33–34 Zinc 99 94 5 5.2

MB-1-41 40–41 Zinc 90 72 18 22.2

MB-1-61 70–72 Zinc 70 91 21 26.1

MB-1-16 15–16 Organic carbon (%) 22.2 24.8 2.6 11.1 4.5

MB-1-31 30–31 Organic carbon (%) 22.1 22.2 .1 .5

MB-1-46 45–46 Organic carbon (%) 23.8 23.5 .3 1.0

LCO-1-9 8–9 Organic carbon (%) 20.5 18.8 1.7 8.9

LCO-1-19 18–19 Organic carbon (%) 17.5 17.6 .1 .8

MB-1-16 15–16 Nitrogen (%) 2.65 3.20 .55 18.8 7.1

MB-1-31 30–31 Nitrogen (%) 2.53 2.57 .04 1.6

MB-1-46 45–46 Nitrogen (%) 2.64 2.57 .07 2.7

LCO-1-9 8–9 Nitrogen (%) 2.12 2.03 .09 4.3

LCO-1-19 18–19 Nitrogen (%) 1.71 1.85 .14 7.9

MB-1-16 15–16 Biogenic silica (wt %) 25.0 23.6 1.4 5.7 9.1

MB-1-31 30–31 Biogenic silica (wt %) 22.9 22.8 .1 .4

MB-1-46 45–46 Biogenic silica (wt %) 23.1 20.4 2.7 12.3

LCO-1-10 10–11 Biogenic silica (wt %) 26.1 27.0 .9 3.4

LCO-1-21 20–21 Biogenic silica (wt %) 5.4 6.8 1.4 23.7

Table A10. Results from quality assurance analysis of replicate core samples from Lac Courte Oreilles and

surrounding areas, October 1999 and July 2001—Continued

[cm, centimeter; %, percent; wt, weight; na, no data]

Field no. Interval 

(cm) Type of data Replicate 1 Replicate 2 Absolute 

difference

Percent 

error

Average

percent error
APPENDIX B 139

 APPENDIX B

Interpretation of Nutrient History for the Main Basin of Lac Courte Oreilles from Diatom 

Assemblages

By Paul J. Garrison 

Aquatic organisms are useful indicators of lake water quality because they are in direct contact with the water 

and are strongly affected by the chemical composition of their surroundings. Most indicator-organism groups grow 

rapidly and are short lived, so the community composition responds rapidly to changing environmental conditions. 

Diatom assemblages are especially useful sets of organisms for paleolimnological analysis. Diatoms are a type of 

algae that possess siliceous cell walls, which enable them to be highly resistant to degradation; moreover diatoms 

are usually abundant, ecologically diverse, and well preserved in sediments. Diatom species have unique features 

(some of which are shown in fig. B1) that enable them to be readily identified. Certain taxa are usually found under 

nutrient-poor conditions, whereas others are more common at elevated nutrient concentrations. Some species float 

in the open-water areas, whereas others are attached to objects such as aquatic plants or the lake bottom. 

By determining changes in the diatom community, it is possible to determine certain water-quality changes that 

have occurred in the lake. The diatom community provides information about changes in nutrient and pH conditions, 

as well as alterations in the aquatic plant community. 

Diatom assemblages were examined from core LCO-2 collected from the deep area of the Lac Courte Oreilles 

in October 1999. The water depth at this site was 30 meters. The top of the core was examined, as was a section at 

40 centimeters that was assumed to represent a time period prior to the late 1800s. 

In the main part of Lac Courte Oreilles, at the present time and historically, the major component of the diatom 

community are those species that float in the open water of the lake (planktonic diatoms; fig. B2). The major species 

of the planktonic diatoms is the chain forming taxa Aulacoseira (fig. B1, left). The second most important diatom 

group is Cyclotella (fig. B1, right), which also float in open water.

The slight decrease in the percentage of Aulacoseira at the present time compared with historical times indicates 

a small increase in nutrients. Cyclotella usually are found under slightly higher nutrient levels than Aulacoseira. It 

is likely this increase has only been very slight, probably on the order of 2-4 micrograms liter-1 of phosphorus over 

the last 100 or more years. There also appears to have been an increase in aquatic plants, as indicated by an increase 

in the diatom Achnanthidium. This diatom typically is attached to submerged plants. This increase in plants is very 

common in northern Wisconsin lakes and results from increased nutrient delivery from watershed disturbance. In 

the case of Lac Courte Oreilles, the possible disturbance sources are cottage development and discharge from cranberry operations.

In summary, the diatom community indicates nutrient concentrations in the middle of Lac Courte Oreilles have 

increased only a small amount over the past 100 years. The aquatic plant community does appear to have increased 

slightly. The diatoms indicate that the overall health of the main body of the lake remains very good. Because this 

core was collected in the deep area of the main lake basin, the diatom community does not reflect changes that may 

have occurred over time in the various bays of the lake. 
140 Nutrient, Trace-Element, and Ecological History of Musky Bay, Lac Courte Oreilles, Wisconsin, as Inferred from Sediment Cores

Figure B1. Electron-micrographs of diatoms Aulacoseira (left) and Cyclotella (right). Both of these diatoms

float in the open water. The diatom on the left is indicative of lower nutrients than the one on the right.
Appendix B 141

Figure B2. Changes in abundance of important diatoms found at present (0–1 centimeters) and presettlement

times (40–41 centimeters).

LAC COURTE OREILLES

Sawyer County

Planktonic Diatoms

80 85 90

0—1 cm

40—41 cm

Cyclotella spp.

0 10 20 30 40

0—1 cm

40—41 cm

Aulacoseira spp.

Percent of total diatoms

0 10 20 30 40 50 60 70 80

0—1 cm

40—41 cm

Achnanthidium spp.

0 5 10

0—1 cm

40—41 cm