Prepared in cooperation with the U.S. Bureau of Reclamation 

Quantifying the Benthic Source of 

Nutrients to the Water Column of Upper 

Klamath Lake, Oregon 

Open File Report 2007–1276 

U.S. Department of the Interior 

U.S. Geological Survey 
Prepared in cooperation with the U.S. Bureau of Reclamation 

Quantifying the Benthic Source of Nutrients 

to the Water Column of Upper Klamath Lake, 

Oregon 

By James S. Kuwabara1, Dennis D. Lynch2, Brent R. Topping3, Fred Murphy4, James L. 

Carter5, Nancy S. Simon6, Francis Parchaso7, Tamara M. Wood8, Mary K. Lindenberg9, 

Katryn Wiese10, Ronald J. Avanzino11

Open File Report 2007–1276

U.S. Department of the Interior 

U.S. Geological Survey 

1 kuwabara@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

2 ddlynch@usgs.gov, U.S. Geological Survey, Portland, OR 

3 btopping@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

4 fmurphy@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

5 jlcarter@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

6 nssimon@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

7 parchaso@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

8 tmwood@usgs.gov, U.S. Geological Survey, Menlo Park, CA 

9 mlinden@usgs.gov, U.S. Geological Survey, Klamath Falls, OR 

10 kwiese@ccsf.edu, City College of San Francisco, San Francisco, CA 

11 avanzino@usgs.gov, U.S. Geological Survey, Menlo Park, CA 
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2007 

Revised and reprinted: 2007 

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Suggested citation: 

Kuwabara, J.S., Lynch, D.D., Topping, B.R. Murphy, Fred, Carter, J.L., Simon, N.S., 

Parchaso, Francis, Wood, T.M., Lindenberg, M.K., Wiese, Katryn, Avanzino, R.J., 2007, 

Quantifying the Benthic Source of Nutrients to the Water Column of Upper Klamath 

Lake, Oregon 

Any use of trade, product, or firm names is for descriptive purposes only and does not 

imply endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the 

individual copyright owners to reproduce any copyrighted material contained within this 

report. 

3
Contents 

Executive Summary ......................................................................................................................7

Benthic flux of nutrien .................................................................7

Dissolved nutrients in ..................................................................8

Geochemistry of lakebed sediments ..........................................................................................8

Potential Management Implications ........................................................................................8

Background.................................................................................................................................10

Objectives ...................................................................................................................................11

Results and Discussion ......12

Benthic flux of nutrients............................................................................................................12

Dissolved nutrients in the water column...................................................................................13

Dissolved organic carbon (DOC) in the water column..............................................................13

Dissolved trace metals in the water column.............................................................................14

Benthic macroinvertebrates .....................................................................................................15

Benthic chlorophyll...................................................................................................................15

Geochemistry of lakebed sediments ........................................................................................16

Study Design and Methods ..18

Biological Parameters .....................................................18

Chemical Parameters...............................................................................................................19

References Cited ........................................................................................................................21

Acknowledgments.......................................................................................................................24

Figures 

Fig. 1

ts to the water column.............

the water column...................

.........................................................................................................

.......................................................................................................

.........................................................

 Sampling Locations for this study of Upper Klamath Lake, OR.......................................25 

Fig. 2 Preparation of pore-water profilers for deployment in Upper Klamath Lake, OR.............26 

Fig. 3 Water-column sampling with Te 27

Tables 

Table 1

flon-coated Niskin bottle................................................

 Sampling locations and location acronyms used in this report....................................28 

Table 2 Summary of dissolved-nutrient benthic fluxes in Upper Klamath Lake, OR ................29 

Table 3 Dissolved-nu

Upper Klam ........................................................30 

Table 4

trient concentrations (micrograms per liter) in the water-column of 

ath Lake, OR .................................

 Dissolved organic carbon (DOC) in the water column of Upper Klamath Lake, 

OR............................................................................................................................31 

Table 5 Dissolved tra ......32 

Table 6

ce metals in the water column of Upper Klamath Lake, OR .............

 Variability of macro- and micronutrient compositions for tributary inputs to Upper 

Klamath Lake, OR....................................................................................................33 

Table 7 Diffusive flux of dissolved iron in Upper Klamath Lake, OR ........................................34 

Table 8 Macroinvertebrate taxonomy of benthic assemblages within Upper Klamath 

Lake, OR ..................................................................................................................35 

Table 9 Benthic chlorophyll and phaeophytin concentrations (in micrograms per square 

centimeter; n=3) at Upper Klamath Lake, OR ..........................................................36 

4
Table 10 Macronutrients (milligrams per gram, mg-g-1) and major elements associated 

with lakebed sediments in pre-bloom conditions (April 2005) in Upper Klamath 

Lake, OR ..................................................................................................................37 

Table 11 Macronutrients (milligrams per gram, mg-g-1) and major elements associated 

with lakebed sediments during the AFA bloom (July 2005) in Upper Klamath 

Lake, OR ..................................................................................................................38 

Table 12 Precision and recovery for sediment Standard Reference Material NIST SRM 

2710 Montana Soil (n=5 analytical replicates)...........................................................39

5
Convers

M

ion Factors 

Inch/Pound to SI 

ultiply By To obtain 

Length 

foot (ft) 0.3048 meter (m) 

Area 

square foot (ft2) 0.09290 square meter (m2) 

square mile (mi2

) 2.590 square kilometer (km2) 

Volume 

gallon (gal) 3.785 liter (L) 

cubic inch (in3

) 0.01639 liter (L) 

Mass 

ounce, avoirdupois (oz) 28.35 gram (g) 

micromolar (μM) molecular weight micrograms per liter (μg-L-1) 

micrograms per liter (μg-L-1) 0.001 milligrams per liter (mg-L-1) 

ton per year (ton/yr) 0.9072 megagram per year (Mg/yr) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32 

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

°C=(°F-32)/1.8 

Vertical coordinate information is referenced to the insert datum name (and abbreviation) here for instance, 

“North American Vertical Datum of 1988 (NAVD 88).” 

Horizontal coordinate information is referenced to the insert datum name (and abbreviation) here for 

instance, “North American Datum of 1983 (NAD 83).” 

Altitude, as used in this report, refers to distance above the vertical datum. 

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 25 °C). 

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms 

per liter (μg/L). 

Abbreviations and Acronyms 

Abbreviations and Acronyms Meaning 

AFA Aphanizomenon flos–aquae 

DOC Dissolved organic carbon 

SRP Dissolved reactive phosphate 

UKL Upper Klamath Lake 

USBR U.S. Bureau of Reclamation 

USGS U.S. Geological Survey 

6
Quantifying the Benthic Source of Dissolved 

Nutrients to the Water Column of Upper 

ke, Oregon 

es S. Kuwabara, Dennis ch, Brent R. Topping, Fred Murphy, James L. 

r, Nancy S. Simon, Francis Parchaso, Tamara M. Wood, Mary K. Lindenberg, Katryn 

Wiese, Ronald J. Avanzino

Executive Summary 

mpling trips were coordinated in April, May and August 2006, and May and July 

2007 to sample the water column and be ath Lake, OR (Fig. 1

Klamath La

By Jam D. Lyn

Carte

Five sa

nthos of Upper Klam ; Table 1), 

, during and after the annual cyanophyte bloom of Aphanizomenon flos–aquae (AFA). A 

as designed ricated to o first high-resolution (centimeterof the vertic gradie minations. Estimates 

based on m ay underestimate benthic flux because so transport across the 

an be enhanced by proces ioirrigation and 

ction. Water-col d benthic ted to help interpret 

patial and temporal trends in diffusive-flux estimates. Data from these samples complement 

005. 

going study provides information necessary for developing process-interdependent 

ate remediation or load-allocation strategies. To 

ior 

 2007, during the summer 

ein 

water column 

cessfully deployed in Howard Bay on 18 April 2006 

during pre-bloom conditions. Refinements in design from that test were incorporated into 15 

 (bloom), 2 August 2006 (post-bloom), 1 May 2007(pre-bloom), 

 July 2007 (bloom) (F

before

pore-water profiler w and fab btain the

scale) estimates al concentration nts for diffusive-flux deter

olecular diffusion m

sediment-water interface c

lute

ses including bioturbation, b

ground-water adve umn an samples were also collec

s

geochemical analyses of bottom-sediments taken from Upper Klamath Lake (UKL) in 2

This on

solute-transport models for the watershed (that is, models integrating physical, geochemical and 

biological processes), and supports efforts to evalu

augment studies funded by the U.S. Bureau of Reclamation (USBR), the Department of Inter

supported an additional full deployment of pore-water profilers in July

AFA bloom. Results from this recent field trip are not fully completed. Data not presented her

will be included in a subsequent publication, scheduled for March 2009. 

 Benthic flux of nutrients to the 

A prototype pore-water profiler was suc

profilers deployed on 31 May 2006

and 9 ig. 2). The profilers provided a high-resolution (centimeter-scale) 

al profile of pore-wa 10 centimeters) the sediment-water interface. 

 on Fick’s Law, thes ine benthic flux of solutes based on 

on. 

Benthic flux of sol red) reactive phosphorus (that is, biologically 

vailable phosphorus, primarily as orthophosphate; SRP) was consistently positive (that is, out of 

the sediment into the overlying water column) and ranged between 0.5 and 6.1 milligrams per 

square meter per day. Assuming a lake area of 200 square kilometers, this converts to a mass flux 

vertic ter chemistry near (within

Based e profiles were used to determ

diffusi

uble (0.2-micron filte

a

7
to the entire lake of 8,000 to 100,000 kilograms over a 3-month AFA bloom season; comparable in

magnitude to riverine inputs (Nutrient-flux discussion). An additional concern related to fish 

toxicity was identified. Dissolved ammonium also displayed consistently positive benthic f

4 to 100 milligrams per square meter per day; also comparable to riverine inputs. In con

dissolved nitrate exhibited a consistently negative 

ranging between -20 to -0.1 milligrams per square 

luxes of 

trast, 

flux (consumed by the sediment) with values 

meter per day. Although taxonomic analyses are 

ongoing, macroinvertebrate densities at least of the order of 105 individuals per square meter 

(Macroinvertebrate discussion), suggest that the diffusive-flux estimates mentioned above may be 

race-metal results (coordinated benthic flux, water-column and 

tributary-inlet data) suggest that the role of iron availability to primary producers in the lake should 

not be overlooked. 

in the water column 

y 

significantly enhanced by bioturbation. 

Although phosphorus is a logical choice for the limiting nutrient when nitrogen-fixing 

cyanophytes dominate, initial t

 Dissolved nutrients 

Soluble reactive phosphorus (SRP) increased in August 2006, relative to April and May, b

as much as an order of magnitude (107.8 + 31.2 up from 7.6 + 7.3 micrograms per liter (μg-L-1), 

averaged over all sampling sites; (Nutrients discussion). Though the 2007 data do not include a 

post-bloom sampling data, SRP concentrations did increase substantially between May 2007 and

July 2007. Dissolved-nitrogen species (ammonium and the sum of nitrate plus nitrite) gradually 

increased between April and May 2006 samplings, but as observed with SRP, an even greater 

increase (at least three-fold and up to order-of-magnitude) was observed between May and Augus

2006. Samples from the Williamson River plume site (WMR) displayed the highest SRP 

concentrations in both April and May 2006 relative to the other sampling sites, but exhibited the 

lowest concentration in August 2006. However, this spatial trend did not recur in 2007 for SRP

and no spatial trends were observed for dissolved nitrogen species in either year. 

t 

, 

 at another Mid-Lake site 

ent of the AFA 

loom. or gain of P between the onset 

ty 

Geochemistry of lakebed sediments 

The concentrations of total phosphorus (P) in bottom sediments of UKL were variable. 

Analyses of bottom sediments indicated that the accumulation or loss of P was patchy during the 

period between the onset and development of an AFA bloom in UKL in 2005. Data for 

concentrations of total P and geochemical species of P at one site south of Bare Island (SBI) 

indicated a loss of P from surface sediment between the onset and development of the AFA bloom. 

In contrast, data for concentrations of total P and geochemical species of P

(MDL) indicated a gain of P in surface sediment between the onset and developm

b The embayment sites (EBB and HDB) indicated no net loss

and development of an AFA bloom in 2005. 

Potential Management Implications 

Evaluation of proposed remediation efforts and load allocations in the Klamath River Basin 

may be linked to a variety of water-quality objectives in Upper Klamath Lake such as: decreasing 

concentrations of bioavailable forms of macronutrients that regulate phytoplankton communi

structure and abundance, decreasing solute loads to down-gradient systems, and reducing the 

impacts of nutrient cycling on biological resources (for example, endangered and commercial fish 

populations as well as consumers of those resources). Because phosphorus is currently considered

the limiting nutrient for the annual blooms of the nitrogen-fixing, cyanophyte Aphanizomenon flos–

8
aquae (AFA), this work provides initial measurements of benthic sources of dissolved 

macronutrients and examines the significance of this source in relation to riverine sources and 

changes in water-column chemistry associated with the summer AFA bloom. In addition to 

phosphorus, initial results presented herein indicate significant ammonia flux from the sediments 

that may have toxicological consequences for fish resources in the lake. This study also provides

initial distributions of dissolved trace-metal and dissolved organic carbon (DOC) concentrations in 

the lake. Some of these trace solutes (for example, iron) also may play a role in regulating 

phytoplankton dynamics in the lake. The information herein is provided as a contribution and will 

assist in future evaluations of proposed management or remediation strategies. Application of the 

pore-water profilers, designed and fabricated for this study, can help locate areas (“hot spots”) of 

particular concern and subsequent emphasis for restoration activities in the lake and other 

peripheral areas in the basin. 

9
Background 

Annual cyanophyte blooms in Upper Klamath Lake generate a source of organic carbon to

the lakebed and hence increase oxygen demand by the sediment. That demand can induce an 

environmental stress for endangered fish populations (Wood and others, 2006). As phosphorus (P) 

is typically the limiting nutrient for those nitrogen-fixing cyanophytes, this project provides initial 

determinations of the internal loading of dissolved macronutrients (phosphorus and nitrogen 

species) not only to help meet the adaptive-management goals of the 5-year plan for Lake 

Restoration (U.S. Fish and Wildlife Service, Hatfield Restoration Program; 

http://www.fws.gov/klamathfallsfwo/ero/2007rfp/2007rfp.pdf), but also to provide comparative 

data critical for source management as described in the Program’s plan for river restoration. These 

data will provide valuable information about the timing, spatial variability, and cause of the benthic 

flux of P to the lake. 

For the past 50 to 100 years large blooms of a near monoculture of Aphanizomenon flos–

aquae (AFA) developed each summer in Upper Klamath Lake (UKL). Because AFA has an active 

buoyancy system that allows surface “scums” to be wind-concentrated, low dissolved oxygen 

concentrations develop in large parts of UKL when these blooms senesce. The resulting hypoxia 

stresses two endangered sucker populations of the shortnose sucker (Chasmistes brevirostris) and 

Lost River sucker (Deltistes luxatus), and can lead to mass mortality of adults, suboptimal year-toyear survival, and poor recruitment. Improving sustainability for sucker populations depends on 

finding ways to improve UKL water quality by decreasing the severity of blooms and shifting the 

algal assemblage away from AFA monocultures. 

Problematic algal blooms are fueled by large external and internal loads of P. It is the 

internal loading from bottom sediments (benthic flux, including diffusion controlled flux and 

bioturbation), however, that appears to cause lake P concentrations to rise from 80 to 250 

micrograms per liter in late spring, typically in June. Developing an understanding of the 

mechanisms controlling this benthic flux, and how long it would persist if external loads could be 

reduced, is necessary for developing sound remediation strategies and for setting realistic 

expectations for water-quality improvements. This sentiment is not new. Forty years prior to this 

report, Miller and Tash (1967) concluded about UKL that, “It is imperative to know the extent to 

which nutrients in the sediments can interchange with the overlying water.” This study provides 

the first benthic-flux determinations for nutrients in UKL, and is part of an interdependent set of 

investigations that responds to the challenge posed by Miller and Tash to examine sediment-water 

interactions in the lake. 

Early hypotheses for internal P loading included: (1) wind-induced resuspension of bottom 

sediments, (2) desorption of P from surface sediments by high pH waters induced by algal 

production, and (3) release of P from ferric oxyhydroxide coatings on sediments exposed to 

reducing conditions during episodic thermal stratifications. These hypotheses have been discounted 

by subsequent studies leaving the question unanswered as to the actual process controlling benthic 

flux (Fisher and Wood, 2001). This issue can best be resolved by directly measuring gradients of 

dissolved ortho-P (and other constituents) across the sediment-water interface, determining 

diffusive benthic-flux rates, and testing additional hypotheses as to the possible biological, 

chemical, and physical interactions that influence those rates. 

Dissolved ortho-P is a particle-reactive solute, which means that it can form surface 

complexes on a variety of mineral and biotic surfaces (Sigg and Stumm, 1981; Goldberg, 1985; 

Kuwabara and others, 1986). As particulate P settles in the lake, it accumulates in the bottom 

10
sediments. Various biogeochemical processes related to changes in acid-base and redox (oxidation-

 near the sediment-water interface can recycle this P and generate a benthic 

st in-

 bed 

ernal loading 

tatively account for internal P loading based on previous mass-balance 

studies ue 

lved 

x 

 in 

er ongoing studies in the lake is synthesized to 

help id 

re the 

hemical 

verlying 

reduction) chemistry

flux of bioavailable P that may far exceed external sources (Kuwabara and others, 2003a). 

Objectives

In an effort to develop tools to facilitate science-based management decisions related to 

water and ecosystem quality in UKL and the associated watershed, this study provided the fir

situ measurements of the benthic fluxes of dissolved nutrients and trace metals between the

sediment and water column of UKL both before and during the period of int

associated with the annual AFA bloom. These benthic-flux measurements provide initial source 

information for various regions of the lake against which the goals of the 5-year Plan for Lake 

Restoration can be measured. Biological measurements also test whether diffusion-controlled 

benthic flux can quanti

, or whether benthic-community composition suggests an enhancement of diffusive flux d

to bioturbation. Because of current considerations stated in the 5-year Plan to “increase humics 

released into the lake”, the study also provides initial measurements of the benthic flux of disso

organic carbon (DOC) to the lake because many trace metals are biologically reactive and comple

strongly with dissolved organic ligands represented by DOC measurements. Furthermore, elevated

concentrations of dissolved iron in pore-waters are an indication of reducing conditions favorable 

for phosphorus remobilization. Where the magnitude of internal loading in the lake is significant

magnitude relative to other solute sources, solute-transport data from previous studies, primary and

ancillary data from this study, and results from oth

entify potentially important biogeochemical mechanisms that regulate internal loading.

This study complements another done in 2005 to examine the role of sediments in the 

internal loading of P to UKL by comparing characteristics of sediment cores collected befo

onset of an AFA bloom, including the concentrations of total P and P associated with geoc

phases, with the characteristics of sediment cores collected after the development of an AFA 

bloom. The hypothesis tested in the 2005 sediment study was that, as a source of P to the o

water column, sediments have quantifiable losses in the concentrations of P in the time period 

between the onset and development of an AFA bloom. 

11
Results and Discussion 

Benthic 

A prototyp

flux of nutrients 

e pore-water profiler was successfully deployed in Howard Bay on 18 April 2006 

(Fig. 1). That test allowed us to refine the profiler design to provide 50 – 60 milliliters of water 

from each of six pore-water depths. After refinements were made, profilers were fully deployed in

triplicate, except where indicated in Table 2, at each of five sampling sites in the lake. 

 The flux of SRP as determined from pore-water concentration gradients was consis

positive (that is, out of the sediment into the overlying water column) and ranged between 0.5 and

6.1 milligrams per square meter per day (

tently 

Table 2). Large-scale (between site) spatial variability

was observed, sometimes at order-of-magnitude levels. Meanwhile, small-scale (within site) 

variability was seen at certain sites to a lesser degree (>30% of mean values). Assuming a lake

area of 200 square kilometers, estimated diffusive flux can be areally averaged to represent a range 

of 100 to 1200 kilograms per day of phosphorus as SRP. Our diffusive-flux measurements are al

comparable in magnitude to the highest pumping load (or discharge) of dissolved and particulate 

phosphorus from the Williamson River reported by Synder and Morace (1997; 77 kilograms per 

day). 

 Extrapolated over a 3-month AFA bloom season, our observed range is 8,000 to 100,000 

kilograms phosphorus as SRP. For comparison, riverine inputs (Kann and Walker, 1999; data from 

years 1991 throught 1998) averaged 21,000 

so 

+ 5,000 kilograms phosphorus as SRP during the 3-

month AFA bloom season. Miller and Tash (1967) estimated that the Wood and Williamson 

Rivers contributed about 43 percent of the total phosphorus to the lake with a daily load, averaged 

over 14 s 

 is 

d 

played consistently positive benthic fluxes 

of 4 to 100 milligrams per square meter per day. Extrapolated over a 3-month AFA bloom season, 

this range is approximately 70,000 to 2,500,000 kilograms of nitrogen as dissolved ammonium. 

The higher fluxes for ammonium relative to SRP reflect higher concentration gradients across the 

sediment water interface despite increasing water-column concentrations for dissolved ammonium 

as the AFA bloom progressed (Table 2

 months, of 460 kilograms per day (approximately 41,000 kilograms of total phosphoru

during the 3-month algal growth season). 

Because the negative logarithm of the equilibrium constant (pK) for the ammonia (NH3) to 

ammonium (NH4

+

) reaction is 9.5 (Hogfeldt, 1982), lakes with extended periods where the pH

>9.5 like UKL (Wood and others, 2006) are locations where elevated ammonia or ammonium 

concentrations are of concern due to potential fish toxicity (Arillo and others, 1981; Randall an

Tsui, 2002). As with SRP, dissolved ammonium also dis

). Using Kann and Walker (1999) again for comparison, the 

riverine inputs for total dissolved inorganic nitrogen (that is the sum of ammonium, nitrate and 

nitrite concentrations) during the 3-month AFA bloom season are 13,000 + 3,000 kilograms. In 

contrast to both dissolved ammonium and SRP, dissolved nitrate exhibited negative fluxes 

(consumed by the sediment) with values ranging between -20 to -0.1 milligrams per square meter 

per day, with the exception of the unreplicated test of 18 April 2006, that generated a slightly 

positive nitrate flux (3 milligrams per square meter per day). 

The growth and subsequent settling of phytoplankton provide a carbon source to microbial 

and macroinvertebrate assemblages near the lakebed. It has been demonstrated that feeding and 

foraging mechanisms by certain macroinvertebrates may significantly enhance the benthic flux of 

solutes (Kuwabara and others, 1999; Boudreau and Jorgensen, 2001). In addition to collecting 

samples for chemical constituents in the lake water column and interstitial waters, replicate samples 

12
were also taken during each sampling event to provide initial information on macroinvertebrate and 

benthic-chlorophyll distributions. Our data thus far indicate benthic macroinvertebrate densities 

d spatially with densities at least of the order of 105

agnitude similar to those reported previously (Strayer, 

1994; C

n 

varied substantially both temporally an

individuals per square meter, an order of m

rane and others, 1997). The magnitude of these macroinvertebrate densities, suggest that 

the diffusive-flux estimates reported herein represent lower bounds for solute benthic fluxes that 

may be physically enhanced by bioturbation. 

 

Dissolved nutrients in the water column 

Dissolved-nitrogen species (ammonium and nitrate plus nitrite) gradually increased betwee

April and May 2006 samplings, but experienced at least three-fold and up to order-of-magnitude 

increases in August 2006 relative to previous dates (Table 3). However, these temporal trends we

not maintained at all stations for the 2007 sampling. Consistent with previous monitoring in the

lake (Wood and others, 2006), concentrations > 0.5 (but < 1.0) milligrams per liter for dissolved 

ammonium were observed at the end of the bloom period in August 2006. Although the upper 

bound of 1 milligram per liter is lower than published acute toxicity values (LC50) for fish and 

other freshwater species (Randall and Tsui, 2002), concentrations of the order of tenths of 

milligrams per liter, as reported herein, have been shown to induce sublethal effects in fish (Daou

and Fer

re 

st 

guson, 1984; LeMarie and others, 2004). Concentrations of dissolved nitrogen species at 

WMR were the lowest on average relative to all other sampling sites, particularly in May 2007. 

SRP also increased in August 2006 relative to April 2006 and May 2006 concentrations 

(overall averages for the April and May versus August 2006 samplings were 7.6 + 7.3 versus 107.8 

+ 31.2 micrograms per liter, respectively). In terms of inter-annual differences, only a minor (that 

is, statistically insignificant) increase was observed for SRP between pre-bloom (April 2006) and 

bloom (May 2006) conditions. In contrast, pre-bloom and bloom conditions in 2007 exhibited 

much greater SRP differences (overall averages of 10.1 + 3.6 and 103 + 15.4 micrograms per liter

for pre-bloom (May 2007) and bloom conditions (July 2007), respectively; Table 3). The samples 

from the Williamson River plume site (WMR) displayed the highest SRP concentrations in both 

April 2006 and May 2006 (that is, pre-bloom and bloom conditions, respectively) relative to the 

other sampling sites, but the lowest SRP among sites in August 2006 (post-bloom conditions). In 

contrast, similar SRP concentrations relative to other sites were observed in 2007 pre-bloom and 

bloom samplings. 

Dissolved silica serves as an essential macronutrient for diatoms but also a ligand that may 

compete in complexation and sorption reactions. Because annual summer blooms are not 

dominated by diatoms, silica was not examined in 2006 field work, but samples for dissolved silica 

were collected in 2007 to provide initial information that might affect our understanding of the 

speciation or partitioning of other ligands like phosphate. Only three sites were sampled for silic

due to budgetary constraints (SBI, EBB and MRM). Water-column concentrations were spatially

consistent in May 2007 (10.8 to 10.9 milligrams Si per liter with a standard error of 0.1 milligrams

Si per liter) and July 2007 (14.6 to 14.9 milligrams Si per liter with a standard error of 0.1 

milligrams Si per liter). Note that silica and organic carbon are the only solutes to be expresse

these units (all others in micrograms per liter). 

a 

d in 

Dissolved organic carbon (DOC) in the water column 

Dissolved organic matter, measured as DOC, is a ligand that can compete for trace-metal 

complexation in the water, and hence affect the remobilization and bioavailability of biologically 

13
reactive trace metals (Kuwabara and others, 1986). For example, Kuwabara and others (1989 and 

2002) noted that spatial trends for certain dissolved trace metals (copper and zinc) in South San 

Francisco Bay and Lahontan Reservoir (mercury) were coincident with DOC. Although DO

concentrations in the water column of UKL were spatially consistent on a given sampling date, 

concentrations taken before and during the AFA bloom (5.8 

C 

+ 0.1 milligrams carbon per liter or 

484 + 12 micromolar carbon; n=26 for April and May 2006 samples) were consistently lower than

observed in August 2006 (8.2 + 0.3 or 687 + 28 micromolar carbon; n= 12), at the conclusion of the 

bloom (Table 4). Similarly in 2007, DOC concentrations increased at all sites as the AFA bloom 

progres

L, 

-

sed. 

 

Dissolved trace metals in the water column 

Trace elements can represent both essential micronutrients as well as highly effective algal 

toxins. In the dissolved phase, trace elements (for example, copper, manganese and zinc) are more 

bioavailable than if particle-bound, and can compete for ligands in both dissolved and particulate 

phases, and hence affect trace-metal speciation and partitioning. During all sampling trips to UK

dissolved cadmium, zinc, and sometimes lead were below the method detection limits of our ICP

MS analyses (Table 5). In terms of spatial trends, dissolved trace-metal concentrations did

significantly between sites on any of the three dates. Dissolved-nickel concentrations were both 

spatial and temporally consistent (0.346 

 not vary 

+ 0.051 micrograms per liter for the mean concentration 

over all trips; n=61). Dissolved manganese and cobalt increased in August 2006 relative to our 

April 2006 and May 2006 samplings, and again between May 2007 and July 2007. In contrast, 

dissolved iron became depleted (less than 5 micrograms per liter) at all five sampling sites by the 

end of the algal-bloom period in August 2006. The fact that SRP increased at the end of the AFA 

bloom (Table 3) while dissolved iron was depleted, suggests that iron availability may play an 

important role in regulating primary productivity in the lake. Dissolved iron associated with 

organic ligands varied considerably (by orders of magnitude) in tributary inputs to UKL (Table 6). 

In May 2007, 83 percent of the variation in dissolved iron was explained by spatial trends in the 

DOC data (that is, the correlation coefficient, r = 0.91). However, in July 2007, the Williamson 

tributary, having the highest DOC and dissolved iron in May, was no longer flowing. With no 

Williamson tributary data in July, the coefficient of determination for dissolved iron on DOC 

decreased to 0.14. In both May and July tributary samples, the correlation between SRP, silica an

DOC remain consist

d 

ently significant (coefficients of determination between 0.73 and 1.00; Table 

6). 

Diffusive flux of iron from the lakebed averages 2.9 + 2.3 milligrams of iron per sq

meter of lakebed per day (

uare 

Table 7). Using the afore mentioned 200 square-kilometer surface area 

estimate, this mean extrapolates to 53,800 kilograms of dissolved iron diffusing into the water 

column over the 3-month AFA bloom. Alternately, using an average lake depth of 2.8 meters 

(Wood and others, 2006), iron flux would be estimated to increase the lake-wide water-column 

concentration of dissolved iron by approximately 1 microgram per liter per day, or approximately 

90 micrograms per liter over the 3-month AFA bloom. The possibility of dissolved iron as

limiting nutrient in the AFA bloom cannot be discounted, even before considering that these fluxes 

are likely to be underestimates due to the possib

 a 

ility of advective flux by bioturbation. 

 should be noted that trace-metal concentrations for the lake and proximal rivers have been 

previou tterson and Settle 

(1976) -

It

sly reported (Miller and Tash, 1967). However, seminal studies by Pa

and later by Fitzwater and others (1982) revealed that the utility of data from all prior trace

metal studies (that is, at least before the mid 1970s) was constrained by problems with sampling 

14
(i.e., the lack of ultra-clean sampling and processing techniques) and analytical methods. The 

analysis of dissolved Zn is particularly susceptible to sample contamination during collection, 

handling and processing (Bruland and others, 1978; Fitzwater and others, 1982). As noted abov

dissolved-Zn concentrations reported here were consistently below a conservative ICP-MS 

detection limit of 1 microgram per liter. In contrast, the lowest lake Zn concentration reported by

Miller and Tash (1967) was 7 micrograms per liter with the majority of measurements above 20 

microgram per liters. 

Ben

e, 

thic macroinvertebrates 

is study includes some initial characterizations of the benthic macroinvertebrate 

assemb ments thus far suggest that 

abunda

Th

lages associated with the 5 lake-sampling sites. Measure

nces of the order of tens of thousands of individuals per square meter are typical in the lake, 

so it is reasonable to assume that bioturbation by the macroinvertebrate assemblage will to some 

extent enhance the diffusive-flux measurements determined by the profiler (Table 8). Flux 

measurements presented herein do not quantify the percentage of the total benthic flux attributable 

to bioturbation. As a point of reference, benthic flux of trace elements and nutrients in Coeur 

d’Alene Lake, ID, a transitional oligotrophic-mesotrophic system impacted by a century of mining 

activities, is diffusion dominated (that is, neglible biological enhancement of benthic flux) becaus

the abundance of macroinvertebrates is sparse (98 + 125 macroinvertebrates per square meter; n= 

12; Kuwabara and others, 2003b) at sampling sites that were examined. In a hypothetical examp

if one assumes that a water column source of phosphorus around 300 micrograms per liter per 

month stimulates the annual summer AFA bloom (Fisher and Wood, 2001), one can estimate that 

bioturbation-enhancement factor of approximately 15 would account for a predominantly benthic 

source (i.e., 300/20; using the average dissolved ortho-P benthic flux from 

e 

le, 

a 

Table 2 and assumin

average water-column depth of 3 meters). The magnitude of this enhancement factor is withi

reason because; (1) in certain aquatic environments, bioturbation and bioirrigation by benthic 

macroinvertebrates can enhance the benthic flux of solutes by orders of magnitude (that is, a 

bioturbation/bioirrigation enhancement factor of tens to hundreds; Charbonneau and Hare, 1997;

Kuwabara and others, 1999), and (2) the benthic flux of dissolved ortho-P is one of many dissol

forms of phosphorus, albeit the most bioavailable form, that may be transported into the water 

column from the underlying sediment. 

g an 

n 

ved 

Benthic chlorophyll 

Benthic-chlorophyll measurements provide an indication of the settled carbon load to the

lake bed as phytoplanktonic bloom conditions wax and wane. This study includes some initial 

measurements of benthic chlorophyll for the lake associated with the 5 sampling/profiling sites 

(Table 9). As one might expect, measurements for benthic chlorophyll varied widely over the 

bloom season (0.4 to 5.0 micrograms chlorophyll per square centimeter) as did the associated 

phaeophytin (3.1 to 14.1 micrograms phaeophytin per square centimeter). In 2006, benthicchlorophyll concentrations decreased at all sites as the bloom progressed, and because 

phaeopigments represent degradative products of chlorophyll, phaeophytin concentrations 

coincidently increased. However in 2007, benthic chlorophylls were significantly lowe

beginn

r at the 

ing of the bloom (that is, during our early May 2007 sampling) and phaeophytin higher than 

in 2006 (Table 9). Hence, the average ratio of benthic chlorophyll to phaeophytin (that is, the 

concentration ratio of chlorophyll to the sum of chlorophyll and phaeophytin is significantly lower 

in 2007 than in 2006. That ratio serves as a coarse indicator of the reproductive status of the 

benthic algal assemblage. When this ratio is high (near 1), pigments are dominated by active 

15
chlorophyll a, indicating a viable algal population that is growing and developing quickly (that 

near maximum growth rates). Conversely, a low ratio (< 0.5) indicates a predominance of 

phaeopigments, associated with: (1) the termination of blooms, (2) degradation or senescence of 

cells settled on the lakebed, or (3) an active benthic fauna that consumes benthic algae and 

generates phaeopigment-rich feces. Because of cell settling and light absorption, this ratio is 

typically higher in the water-column than in the bottom sediments (Carmen and others, 1997). 

Note that all tabulated r

is, 

atios (all dates and locations) are < 0.5 with lowest values in 2007 of <0.1. 

In 2006, chlorophyll-a concentrations were monitored by the USGS Oregon Water Science Center 

at HDB and WMR (http://or.water.usgs.gov/projs_dir/klamath_ltmon/). The highest benthicchlorop erved in 

ic-

 similar 

hyll concentrations (and chlorophyll to phaeopigment ratios) at these sites were obs

April, prior to the AFA bloom in the water column. In 2007, those pre-bloom peaks in benth

chlorophyll concentrations were not observed and phaeophytin concentrations were elevated prior 

to the AFA bloom, as they were after the bloom in August 2006. If the annual and seasonal 

components to the variability of parameters that characterize the benthic environment are of

magnitudes, as suggested by this initial data set (Table 9), it maybe prudent in subsequent 

monitoring studies to quantify and isolate variability over multiple time scales. 

 

Geochemistry of lakebed sediments 

 P Concentrations

Concentrations of total P in the April 2007 sediment samples (Table 10) ranged from 0.23 

mg/g to 1.11 mg/g DW. Concentrations of total P in the July 2007 sediment samples (Table 

11) ranged from 0.24 to 1.07. 

 P Speciation 

Loosely bound P: Data for P concentrations in extractions using 1M MgCl2 (pH=8) 

indicate that approximately 10 to 15 percent of the concentration of total P in the surfac

sediment from the cores collected for this study is loosely bound phosphate. In all cores th

concentration of easily desorbed P is largest in sediment closest to the sediment-water 

interface (<5 cm depth). 

P associated with poorly crystalline Fe oxides: The largest concentrations of phosp

associated with poorly crystalline

e 

e 

hate 

 Fe oxides are in surface sediments from EBB and SBI 

(Table 10; Table 11). As with the loosely bound P, the concentrations of P sorbed to poorly 

crystalline Fe oxides were largest near the sediment-water interface (<5 cm depth). 

P associated with carbonates and low energy bonds in organic matter: One molar 

HCl extracted approximately 10 to 20 percent of total P in both the April and July cores 

(Tables 10 and 11, respectively) collected at the EBB, SBI, and HDB sites. One molar H

extracted approximately 10 to 30 percent of the total P in the April and July cores collec

at the MDL site. 

Organic P: The residual sediment material remaining after treatment with the extrac

sequence is considered free of inorganic matter and therefore is calculated to contain

organic fraction of P. Calculated average values for the percent of total P represented by

organic P was 71 

Cl 

ted 

tion 

 the 

+ 10 percent for all samples collected in April 2005, and 82 + 12 percent 

for all samples collected in July 2005. 

16
 Metals 

Concentrations of total Fe, total Al and total Ca are similar in sediments from all co

depths with the following exceptions (

res at all 

Table 10; Table 11). Concentrations of total Fe in 

sediment cores from EBB are larger than the concentrations of total Fe in cores from

other three sites in this study. Concentrations of total Al and total Ca in the top 5 cm o

sediment are larger in cores from MDL than in the cores from other study sites. 

Organic C and N 

The organic compound used as a primary standard (acetanilide) contains 71.05 percent

carbon. Replicate samples provided concentrations of 71.28 

 the 

f 

+ 0.20 percent of C (n= 5). On 

average, concentration data for percent C could be approximately 0.01 percent larger tha

the true concentration. There were no differences between the concentrations of C in 

samples analyzed by flash oxidation of the sample and separation of the gaseous prod

before and after treatment with hydrochloric acid (HCl). The similarity in the concentrations 

of C in samples before and after treatment with HCl indicates that the C concentrati

represent organic C with negligible contributions of inorganic C. 

n 

ucts 

ons 

17
Stud

the wat

each an others, 

2001; Kuwabara and others, 2003a). 

06, 

2 Augu

bentho

y Design and Methods 

The protocol described in this section focuses on method applications in this sampling of 

er column and benthos in UKL. Details (for example, quality control specifications) for 

alysis have been previously documented (Woods and others, 1999; Praskins and 

Within UKL, sampling was performed on five trips beginning 18 April 2006, 31 May 20

st 2006, 2 May 2007 and 9 July 2007, to chemically characterize the water column and 

s (Fig. 1; Table 1). A non-metallic pore-water profiler was designed and fabricated for this 

study (Fig. 2). In addition to water just above (approximately 1 centimeter) the sediment-water 

e, samplers collected interstitial water from five depths within the top 10 centimeters of the

, with fritted polypropylene probes at 1, 2, 3.3, 5.5 and 10 cm, to characterize dissolvedertical gradients (that is, six independent sampling circuits). Each sampling circuit collected 

 (0.2 micron) water into acid-washed 60-milliliter syringes. After being lowered onto th

, the device was tripped mechanically to begin sample collection a

interfac

lakebed

solute v

filtered e 

lakebed nd retrieved 

approximately 24 hours later. Dye experiments indicated that this extended sampling period 

avoided short circuiting of samples between depths and along device surfaces. After retrieval, the 

sample syringes were valved closed, placed in argon-filled bags and refrigerated in darkness for 

chemical analyses. On 18 April 2006, a prototype of the pore-water profiler was tested at the longterm monitoring site in Howard Bay (HDB), providing the first set of nutrient data to estimate 

diffusive flux from the lake sediments. Based on that initial trip, the design of the profiler was 

refined and 15 units were fabricated. During four subsequent sampling events, pore-water profilers 

were deployed in triplicate at five locations in UKL corresponding to long-term USGS monitoring 

sites in the lake (Wood, unpublished). A patent application has been submitted for this pore-water 

profiler. Flux calculations, based on Fick’s Law, assume that the process is diffusion controlled 

with solute-specific diffusion coefficients (Li and Gregrory, 1974; Applin 1987). Hence, the 

calculated benthic flux of dissolved solutes based on pore-water profiles can be enhanced by 

bioturbation, bioirrigation, wind resuspension, and potential ground-water inflows. 

At each profiler-deployment site, water-column samples for dissolved (0.2-micron filtered) 

nutrients, trace elements and dissolved (0.7-micron filtered) organic carbon were collected with a 

fluoroethylene polymer-coated Niskin bottle (General Oceanics; Fig. 3) to minimize contamination 

and crossover of analytes. Benthic samples for macroinvertebrate taxonomy and benthic 

chlorophyll were also obtained by sub-coring replicate grab samples. 

Sampling methods have been previously described (Kuwabara et al. 2003b), but details are 

provided below. At each site, the following samples were collected, unless otherwise noted: 

Biological Parameters 

1. Benthic invertebrate sampling: After water-column sampling was completed at each sampling 

site, three deployments of an Ekman grab sampler (15 x 15 centimeter cross section) were used to 

collect replicate samples for macroinvertebrate taxonomic analyses. The sieved samples (500-

micrometer mesh) were fixed with 10-percent buffered formalin, later transferred to 70-percent 

ethanol, then sorted at 10× magnification and identified to the lowest practicable taxonomic level. 

Samples were stained with Rose Bengal to facilitate sorting. No subsampling was used. 

2. Benthic chlorophyll-a: At each lake site, surficial sediment (that is, the top 0.5 centimeters of 

lakebed material) was collected from a fresh Ekman grab and stored refrigerated in a plastic Petri 

18
dish within a sealed plastic bag. Each dish was sub-sampled in triplicate for benthic chlorophyll-a. 

The surficial sediment for each replicate was collected on a glass-fiber filter and buffered with 1 

 Water was removed from the buffered samples by vacuum at less 

d cell lysis. Samples were then frozen in darkness for 

d 

d 

e-deionization 

e wet 

 Science 

d precision of the microwave 

milliliter of magnesium carbonate. 

than 5 pounds per square inch to avoi

preservation until spectrophotometrically analyzed by methods described in Thompson and others 

(1981) and Franson (1985). 

Chemical Parameters 

1. Dissolved trace elements: Water-column samples were collected in duplicate in 250-milliliter acidwashed high-density polyethylene bottles, filtered (0.2-micrometer polycarbonate membrane) an

acidified (pH 2) to provide dissolved trace-metal information for the lake by flow-injection 

inductively coupled plasma mass spectrometry (ICP-MS; Topping and Kuwabara, 1999; Topping an

Kuwabara, 2003a). 

2. Dissolved organic carbon (DOC): Dissolved organic carbon samples were also collected in 

duplicate in baked 60-milliliter glass bottles with acid-washed fluoroethylene-polymer caps, filtered 

(0.7-micron baked glass-fiber filter) for analysis by high-temperature combustion (Qian and Mopper, 

1996; Vandenbruwane and others, 2007). Potassium phthalate was used as the standard. Low-DOC

water (blanks less than 40 micrograms organic C per liter) was generated from a doubl

unit with additional ultraviolet treatment (Milli-Q Gradient, Millipore Corporation). 

3. Dissolved nutrients: Nutrient samples were filtered (0.2-micron polycarbonate membranes) and 

immediately refrigerated in darkness. Unlike trace-metal samples, nutrient samples were not 

acidified. Concentrations for dissolved (0.2-micron filtered) nitrate, ammonia, orthophosphate (SRP)

and silica were determined by automated spectrophotometry (Franson, 1985). 

4. Geochemistry of lakebed sediments: In April, before the onset of an AFA bloom, and in July, 

after development of an AFA bloom, a long (27 cm) and a short (10 cm) sediment core were 

collected at the Ball Bay (EBB), Bare Island (SBI), Howard Bay (HDB) and Mid Lake (MDL) sites 

in UKL. 

 Cores were sampled at 1-cm intervals to a depth of 5 cm from the sediment water interface. 

Two-cm intervals were collected between depths of 5 and 15 cm; 3-cm intervals were collected 

between depths of 15 and 27 cm. Individual intervals of the cores were weighed, frozen and, 

subsequently, freeze-dried. Samples were ground to a 250 μm particle size. The weights of th

and dry sediment were recorded and water content was calculated. 

 In preparation for determination of total P, major cations, and trace metals, approximately 

0.1 g of each sample was digested with concentrated nitric and hydrofluoric acids using a microwave

digestion system (CEM Corporation). Nitric and hydrofluoric acids were added in two steps. Diluted 

digests were analyzed for trace metals using inductively-coupled plasma mass spectroscopy (ICPMS). Certified reference material, NIST SRM 2710, Montana soil, (National Institutes of

and Technology, 2003) was analyzed to determine the accuracy an

technique (Table 12). This SRM was included in all sets of analyses and the results of the analyses of

the standard sediment determined the acceptability of chemical data. 

 Total P was determined using diluted microwave digestion solutions and the molybdenum

s colorimetric method for SRP (dissolved orthophosphate included) was used to 

ntrations in all samples. The method detection limit for total P is 0.14 mg g-1 DW 

lude 

organic P. 

fied 

th 

blue method. Thi

determine P conce

sediment. The microwave digestion procedure described above converts all forms of P in sediment

samples to orthophosphate. Details of the method are given in Simon et al. (2005). 

Phosphorus Speciation in sediments included determining concentrations of P in four 

geochemical phases. These forms of P are operationally defined by chemical extractions and inc

(1) loosely bound P, (2) P associated with poorly crystalline Fe oxides, (3) P associated with 

carbonates or bound in low-energy bonds to organic matter, and (4) residual P including 

The sequential extraction scheme used in this study was the method of Ruttenberg (1992) modi

for a smaller sample size than is used in the published method. Loosely bound P was extracted wi

1M MgCl2 (pH=8). A solution of bicarbonate-citrate (pH=7.7) plus dithionite was used to extract P 

19
from poorly crystalline Fe oxides. Extraction with 1M HCl was used to remove P sorbed to 

carbonates, hydrolysable organic P and P bound to metals in organic matter. 

 aluminum (Al), calcium (Ca), copper (Cu), and iron (Fe) in sediment 

samples were determined using ICP-AES. Microwave digests of sediment samples were diluted with 

 acid in preparation for ICP-AES analysis. 

ory study of methods used for analyses was run using the NIST SRM 2710 to 

Organic P was determined by subtracting the sum of the concentrations of inorganic P extracted 

from sediment samples from the concentration of total P in each sediment sample. 

Metals: Concentrations of

0.05 percent nitric

 A laborat

determine the precision and recovery of concentrations of P and metals known to be related to P in 

sediments. Table 12 details the results of this quality assurance study. 

aration of the gaseous products and infrared detection. A subset of sediment 

Organic carbon (C) and nitrogen (N) were determined by using 20 mg of freezedried and ground sediment samples. Flash oxidation of each sample was followed by 

chromatographic sep

samples was treated with HCl to ensure removal of carbonates and analyzed for C and N 

concentrations. Samples from MDL, the site where Ca concentrations in sediment were the largest 

determined in this study, were included in the subset of sediment samples. 

20
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23
A

ot

n 

co ) 

an is 

on

cknowledgments 

The authors are grateful for critical logistical support from R. Shively, S. Vanderkooi and 

her personnel from the USGS Field Office in Klamath Falls, OR, and from the Oregon Water 

Science Center. Macroinvertebrate taxonomic analyses by S.V. Fend are appreciated. Participatio

in field studies by A. Engelstad, S. Foster, V. Greene and B. Swift was critical to its successful 

mpletion. The Klamath Falls Office of the USBR (Funding Agreement Number 06AA204159

d the USGS Toxic Substances Hydrology Program are also acknowledged for support of th

going work. 

24
Fig. 1. Sampling Locations for this study of Upper Klamath Lake, OR 

W122o 0’ W121o 50’ 

EBB 

HDB 

0 5 10 km 

MRM 

SBI 

WMR 

Boat Ramp 

MDT 

MDL 
Fig. 2. Preparation of pore-water profilers for deployment in Upper Klamath Lake, 

On-site profiler assembly 

(May 31, 2006) 

Profiler deployment and r(May 31 and June 1, 2006
Fig. 3. Water-column sampling with Teflon-coated Niskin bottle 
Table 1. Sampling locations and location acronyms used in this report (See map at Fig. 1). 

Site Location Coordinates

Location Acronym North Latitude West Longitude

Howard Bay HDB 42o

 19.550' 121o 55.000'

Modoc Rim MRM 42o

 24.622' 121o 51.874'

Entrance to Ball Bay1 EBB 42o

 25.313' 122o 0.966'

Williamson River plume WMR 42o

 27.334' 121o 57.161'

South of Bare Island SBI 42o

 24.572' 121o 54.637'

Mid-Lake continuous monitoring site MDL 42o

 23.200' 121o 51.985'

Main Trench north of Howard Bay MDT 42o

 23.085' 121o 55.637'

1

 Ball Bay location sampled April 18, 2006 was approximately 1 kilometer south from EBB, 

 and was too shallow for sampling at multiple depths.
Table 2. Summary of dissolved-nutrient fluxes for Upper Klamath Lake, OR. 

18-Apr-06 Ortho-P Nitrate Ammonium

Water-column temperature = 7.0 oC

Prototype test - only one sampler

Site: Howard Bay Code: HDB 0.40 mg-m-2-day-1 79 kg-d-1 0.01 mg-m-2-day-1 3 kg-d-1 23.06 mg-m-2-day-1 

31-May-06 Ortho-P Nitrate Ammonium

Water-column temperature = 14.0 to 15.8 oC Site Site Site Site Site Site Site Site Site Site 

Average StDev Average StDev Average StDev Average StDev Average StDev 

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) 

1 Howard Bay HDB 0.99 0.38 198 76 -0.11 0.07 -23 15 4.46 0.65 

2 Williamson River Plume WMR 2.50 1.57 500 315 -0.63 0.30 -127 60 3.55 0.47 

3 Entrance to Ball Bay EBB 2.17 2.33 651 388 -0.22 0.20 -65 21 12.17 0.67 

4 Modoc Rim MRM 0.46 0.18 92 36 -0.06 0.01 -12 2 4.62 4.52 

5 South of Bare Island SBI 1.69 1.10 338 219 -0.15 0.02 -31 3 4.30 4.36 

2-Aug-06 Ortho-P Nitrate Ammonium

Water-column temperature = 19.2 to 20.3 oC Site Site Site Site Site Site Site Site Site Site 

Average StDev Average StDev Average StDev Average StDev Average StDev 

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) 

1 Howard Bay HDB 6.09 4.25 1218 851 -2.87 1.71 -575 341 133.86 59.34 

2 Williamson River Plume WMR 0.95 0.70 189 140 -5.84 2.33 -1168 466 40.89 40.52 

3 Entrance to Ball Bay EBB 5.23 2.02 1045 403 -22.72 14.76 -3030 3353 106.58 33.93 

4 Modoc Rim MRM 0.43 0.06 85 11 -1.27 0.47 -254 94 25.46 29.50 

5 South of Bare Island SBI 1.28 0.86 256 171 -1.53 0.03 -305 5 11.03 5.55 

2-May-07 Ortho-P Nitrate Ammonium 

Water-column temperature = 12.4 to 12.8 oC Site Site Site Site Site Site Site Site Site Site 

Average StDev Average StDev Average StDev Average StDev Average StDev 

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) 

1 Howard Bay HDB 1.06 0.01 211 3 -1.10 0.96 -331 37 6.30 5.47 

2 Williamson River Plume WMR 0.49 0.11 98 22 -0.87 0.86 -260 118 7.01 6.15 

3 Entrance to Ball Bay EBB 3.54 4.39 708 877 -3.16 0.46 -588 101 5.93 5.46 

4 Modoc Rim MRM 0.76 0.15 153 30 -1.95 0.22 -389 44 6.85 2.00 

5 South of Bare Island SBI 1.83 0.65 365 130 -2.34 0.41 -467 81 9.20 4.63 

10-Jul-07 Ortho-P Nitrate Ammonium 

Water-column temperature = 21.4 to 23.2 oC Site Site Site Site Site Site Site Site Site Site 

Average StDev Average StDev Average StDev Average StDev Average StDev 

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1) (mg-m-2-day-1) (mg-m-2-day-1) 

1 Howard Bay HDB 1.78 0.35 355 71 -0.04 0.02 -5 5 28.08 13.52 

2 Williamson River Plume WMR 6.96 2.90 1393 581 -0.12 0.02 -25 4 19.49 5.10 

3 Entrance to Ball Bay EBB 5.03 0.80 1006 159 -0.01 0.01 -2 2 58.73 37.98 

4 Modoc Rim MRM 0.78 0.50 156 101 -0.11 0.00 -23 0 12.72 5.60 

5 South of Bare Island SBI 1.17 0.80 235 161 -0.05 0.06 -9 12 9.64 1.17 

By comparison, the highest pumping-station flux from the Williamson River ~ 77 kg-d-1 By comparison, the highest pumping-station flux from the William

 (for total P, from Table 11, Synder and Morace, 1997) 28205 kg-yr-1 (for total N, from Table 11, Synder and Morace

Riverine flux for total P (from Table 2, Miller and Tash, 1967) ~ 461 kg-d-1 Riverine flux for total N (from Table 2, Miller and T

168246 kg-yr-1 

Hypothetical Example: If one assumes: (1) an average dissolved ortho-P benthic flux of 

2 mg-m-2-day-1 from the tabulated values above, and (2) an average water-column 

depth of 3 meters a bioturbation-enhancement factor of approximately 15 (or 300/20) would be required to provide 300 micrograms per liter of dissolved ortho-P to the water column in a month to stimulate an AFA bloom. 
Table 3. Dissolved-nutrient concentrations (in ppb or micrograms per liter with standard deviations, stdev; n=2) -

in the water-column of Upper Klamath Lake, OR. 

Ortho-P N+N NH4 Si

(ug-P)-L-1 stdev (ug-N)-L-1 stdev (ug-N)-L-1 stdev (ug-Si)-L-1 stdev

HDB 18-Apr-06 1.8 0.2 3.0 0.4 8.2 1.1 NA1

31-May-06 2.2 0.9 8.8 0.6 26.6 6.8 NA

2-Aug-06 94.6 0.3 75.5 0.6 285.4 14.1 NA

2-May-07 17.4 1.2 156.3 1.1 169.2 10.3 NA

10-Jul-07 122.3 8.2 10.2 0.3 428.4 28.0 NA

WMR 18-Apr-06 30.0 0.0 6.2 0.2 11.3 0.4 NA

31-May-06 25.3 3.8 9.4 0.9 24.7 9.5 NA

2-Aug-06 83.5 6.2 95.8 0.4 82.8 48.8 NA

2-May-07 8.7 1.0 108.3 2.1 62.7 2.6 NA

10-Jul-07 96.9 10.6 16.4 1.0 55.9 46.4 NA

EBB 18-Apr-062 4.6 0.7 2.8 0.3 7.5 0.1 NA

31-May-06 3.9 0.9 15.4 0.7 37.8 13.5 NA

Shallow 2-Aug-06 130.0 1.2 60.5 3.3 789.9 37.5 NA

2-May-07 9.0 2.2 162.7 1.5 176.5 8.8 10900 100

10-Jul-07 84.0 11.8 6.6 0.6 175.0 56.6 14600 100

Deep 31-May-06 11.0 0.8 17.2 0.4 66.0 1.2 NA

2-Aug-06 103.1 1.2 51.8 0.7 556.2 4.5 NA

2-May-07 8.0 1.4 161.8 3.7 193.6 23.5 NA

10-Jul-07 121.3 12.5 13.5 1.1 479.1 53.6 NA

MRM 31-May-06 9.0 0.7 5.3 0.3 21.5 3.7 NA

2-Aug-06 101.7 1.5 93.1 2.6 72.5 2.7 NA

2-May-07 8.2 0.0 176.2 0.4 184.0 9.2 10800 100

10-Jul-07 97.7 8.6 14.3 1.0 10.1 0.0 14800 150

SBI 31-May-06 3.1 0.8 14.4 1.5 29.6 5.3 NA

2-Aug-06 133.8 4.8 112.7 1.0 748.7 12.0 NA

2-May-07 9.2 2.4 169.3 0.0 198.2 13.9 10800 100

10-Jul-07 95.7 4.9 9.3 1.5 438.5 86.3 14865 100

MDL 18-Apr-06 1.0 0.3 2.0 0.0 1.4 0.0 NA

MDT

Shallow 18-Apr-06 2.4 0.2 4.5 1.3 11.9 4.2 NA

Mid-depth 18-Apr-06 2.2 0.1 4.7 1.4 8.5 0.7 NA

Deep 18-Apr-06 2.7 0.3 3.7 1.1 10.0 1.7 NA

1

 "NA" indicates that samples were not analyzed for this constituent. 

2

 Ball Bay location sampled April 18, 2006 was approximately 1 km south from EBB, 

and was too shallow for sampling at multiple depths
B 400 19 4.8 0.2

A 632 8 7.6 0.1

B 644 14 7.7 0.2

A 483 2 5.8 0.0

B 498 19 6.0 0.2

A 652 12 7.8 0.1

B 691 9 8.3 0.1

A 399 5 4.8 0.1

B 402 9 4.8 0.1

A 612 19 7.3 0.2

B 615 4 7.4 0.0

A 497 9 6.0 0.1

B 516 5 6.2 0.1

A 641 4 7.7 0.0

B 615 11 7.4 0.1

A 401 8 4.8 0.1

B 402 12 4.8 0.1

A 628 5 7.5 0.1

B 603 25 7.2 0.3

MDL A 436 10 5.2 0.1

B 442 6 5.3 0.1

MDT

Shallow A 487 2 5.8 0.0

B 480 5 5.8 0.1

Mid-depth A 483 9 5.8 0.1

B 443 5 5.3 0.1

Deep A 453 9 5.4 0.1

B 446 4 5.4 0.1

1

 "95% ci" stands for 95% confidence interval

2

 Ball Bay location sampled April 18, 2006 was approximately 1 km south from EBB, and was too shallow for sampling at multiple depths

MRM

SBI 1-Jun-06

2-Aug-06

2-Aug-06

10-Jul-07

2-May-07

1-Jun-06

10-Jul-07

18-Apr-06

18-Apr-06

18-Apr-06

10-Jul-07

18-Apr-06

2-May-07
B 0.591 0.003 <DL <DL 0.327 0.003 27 5 0.012 0.000 6.7 0.11 0.108 0.002

A 0.613 0.003 <DL <DL 0.345 0.002 38 5 <DL 13.4 0.03 0.067 0.000

B 0.657 0.009 <DL <DL 0.445 0.002 37 5 <DL 14.0 0.09 0.068 0.000

A 0.477 0.002 <DL <DL 0.345 0.004 <DL <DL 10.3 0.04 0.103 0.002

Deep B 0.486 0.002 <DL <DL 0.364 0.003 <DL <DL 14.7 0.07 0.105 0.001

A 0.555 0.004 <DL <DL 0.282 0.015 23 5 0.012 0.000 3.4 0.05 0.065 0.000

B 0.547 0.001 <DL <DL 0.261 0.007 22 5 0.024 0.000 3.3 0.04 0.062 0.001

A

B 0.486 0.009 <DL <DL 0.259 0.008 16 5 <DL 4.9 0.24 0.088 0.000

A 0.619 0.007 <DL <DL 0.361 0.002 40 5 <DL 12.0 0.09 0.068 0.001

B 0.621 0.007 <DL <DL 0.361 0.003 39 5 <DL 11.3 0.05 0.069 0.001

A 0.533 0.007 <DL <DL 0.355 0.001 <DL <DL 5.5 0.02 0.106 0.002

B 0.571 0.002 <DL <DL 0.386 0.004 <DL <DL 5.4 0.05 0.149 0.001

A 0.532 0.004 <DL <DL 0.258 0.009 17 5 0.043 0.001 2.6 0.03 0.061 0.000

B 0.520 0.006 <DL <DL 0.265 0.002 21 5 0.014 0.000 2.7 0.02 0.059 0.001

A 0.624 0.004 <DL <DL 0.329 0.004 71 5 0.012 0.001 7.5 0.08 0.117 0.001

B 0.620 0.008 <DL <DL 0.315 0.002 32 5 0.004 0.000 4.6 0.02 0.117 0.001

A 0.649 0.005 <DL <DL 0.370 0.010 55 5 <DL 6.2 0.02 0.071 0.001

B 0.627 0.007 <DL <DL 0.384 0.008 40 5 <DL 5.9 0.04 0.066 0.001

A 0.496 0.003 <DL <DL 0.362 0.010 <DL <DL 25.7 0.12 0.098 0.001

B 0.510 0.006 <DL <DL 0.353 0.007 <DL <DL 23.6 0.05 0.098 0.001

A 0.564 0.008 <DL <DL 0.279 0.005 24 5 0.019 0.004 1.7 0.04 0.075 0.002

B 0.532 0.006 <DL <DL 0.274 0.014 26 5 0.013 0.001 1.8 0.02 0.062 0.001

A 0.659 0.006 <DL <DL 0.381 0.009 79 5 0.025 0.001 11.3 0.03 0.123 0.002

B 0.736 0.009 <DL <DL 0.460 0.003 191 5 0.063 0.000 20.6 0.08 0.139 0.002

MDL A 0.525 0.008 <DL <DL 0.343 0.002 41 5 0.003 0.001 0.8 0.01 0.048 0.002

B 0.517 0.004 <DL <DL 0.353 0.009 40 5 0.003 0.001 0.7 0.00 0.047 0.000

MDT A 0.555 0.002 <DL <DL 0.386 0.006 45 5 0.004 0.001 1.9 0.01 0.056 0.001

Shallow B 0.537 0.002 <DL <DL 0.378 0.006 45 5 0.004 0.001 1.8 0.01 0.055 0.000

A 0.558 0.003 <DL <DL 0.374 0.006 41 5 0.003 0.000 1.9 0.02 0.055 0.001

Mid-depth B 0.536 0.005 <DL <DL 0.372 0.005 40 5 0.002 0.000 2.0 0.02 0.054 0.000

A 0.542 0.005 <DL <DL 0.387 0.004 42 5 0.005 0.001 2.4 0.01 0.054 0.001

Deep B 0.576 0.002 <DL <DL 0.395 0.004 43 5 0.003 0.000 2.0 0.01 0.054 0.001

Cu error Cd error Zn error Ni error Fe error Pb error Mn error Co error

Detection limits: ~0.002 ppb ~1 ppb ~5 ppb ~0.002 ppb

1

 "95% ci" stands for 95% confidence interval

2

 Ball Bay location sampled April 18, 2006 was approximately 1 km south from EBB, and was too shallow for sampling at multiple depths

Rep A appeared to be contaminated

2-May-07

31-May-06

2-Aug-06

EBB

MRM

SBI

31-May-06

2-Aug-06

31-May-06

2-Aug-06

2-May-07

10-Jul-07

18-Apr-06

18-Apr-06

18-Apr-06

18-Apr-06

10-Jul-07

10-Jul-07

10-Jul-07

2-May-07
Table 6. Variability of macro- and micronutrient compositions for tributary inputs to Upper 

May 1, 2007 

DOC Iron1 To

Replicate (mg-L-1) 95%ci DOC (uM) 95%ci (μg-L-1) 95%ci (

Spring Creek A 0.41 0.01 34 1 < 5 

B 0.39 0.00 33 0 < 5 

Sprague River A 3.03 0.01 252 1 31 1 

B 3.10 0.08 258 7 16 1 

Wood River A 1.38 0.02 115 2 77 1 

B 1.32 0.01 110 1 78 1 

Williamson River A 17.69 0.42 1474 35 177 3 

B 19.73 0.62 1644 52 179 2 

1 If the dissolved iron data is regressed against DOC, the coefficient of determination (r 2) = 

or the correlation coefficient (r) between dissolved iron and DOC = With the exception of the Sprague River, this correlation between dissolvBy comparison, the correlation coefficients for dissolved iron with Total Psilica are -0.54, -0.61, and -0.65, respectively. 

2 Phosphorus and silica stream data from USGS NWIS database [http://nwis.waterdata.usgs.gov/usa/nwis/qw

Jul 9, 2007 

DOC Iron T

Replicate (mg-L-1) 95%ci DOC (uM) 95%ci (μg-L-1) 95%ci (

Spring Creek A 0.82 0.03 68 3 < 5 

B 1.32 0.06 110 5 < 5 

Sprague River A 2.84 0.04 237 4 72 0 

B 2.69 0.12 225 10 32 0 

Wood River A 1.65 0.02 138 2 104 1 

B 1.71 0.10 142 9 97 2 

Williamson River No discharge 
Average StDev Average StDev

Site # Site Location Site Code (mg-m-2

-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1)

1 Howard Bay HDB 0.56 0.46 112 91

2 Williamson River Plume WMR 2.03 0.33 405 66

3 Entrance to Ball Bay EBB 4.60 2.32 920 463

4 Modoc Rim MRM 0.27 0.25 55 50 Only 2 replicates

5 South of Bare Island SBI 0.86 0.38 172 77

2-May-07 Dissolved Iron

Water-column temperature = 12.4 to 12.8 o

C Site Site Site Site

Average StDev Average StDev

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1)

1 Howard Bay HDB 2.62 1.16 524 231 Only 2 replicates

2 Williamson River Plume WMR 3.92 0.66 784 133 Only 2 replicates

3 Entrance to Ball Bay EBB 3.41 1.83 682 365

4 Modoc Rim MRM 4.95 6.16 989 1231

5 South of Bare Island SBI 4.42 0.78 885 157

10-Jul-07 Dissolved Iron

Water-column temperature = 12.4 to 12.8 o

C Site Site Site Site

Average StDev Average StDev

Site # Site Location Site Code (mg-m-2-day-1) (mg-m-2-day-1) (kg-d-1) (kg-d-1)

1 Howard Bay HDB 0.50 0.31 101 63

2 Williamson River Plume WMR 3.71 1.93 742 385

3 Entrance to Ball Bay EBB 3.70 2.89 740 577

4 Modoc Rim MRM 0.85 0.41 171 81

5 South of Bare Island SBI 0.34 0.14 69 28

average Fe flux in mg/m2/day: 2.9

ug/L of Fe per day distributed to entire water column: 1.0
Table 8. Macroinvertebrate taxonomy of benthic assemblages within Upper Klamath Lake, OR1 

HDB MDL EBB2 WMR MD

Insecta Plecoptera Malenka 

Coleoptera Dubiraphia larva Diptera cf. Chironomus 33863 89 1Diptera Chironomini (Harnischia complex) 89 533 51Diptera Chironomini sp. A Diptera Chironomini (e.i.) 6844 44 7421 27908 66Diptera Tanytarsini 1378 400 39774 Diptera Tanypodinae 3200 89 1333 444 19

Crustacea Ostracoda Ostracoda 2311 2000 1200 

Copepoda Cyclopoida 222 178 267 3200 2Copepoda Calanoida Copepoda Harpacticoida 89 1067 311

Cladocera Daphniidae 533 Cladocera Chydoridae 

Amphipoda Hyalella 44 

Acari Acari cf. HygrobatesAnnelida Oligochaeta cf. Sparganophilus 

Oligochaeta Lumbriculus Oligochaeta Kincaidiana freidris 

Oligochaeta Tubificidae 75992 2889 2044 5688 23Hirudinea Helobdella 89 444 44 11

Hirudinea leech (imm.) Polychaeta Manayunkia 4000 28619 

Mollusca Pelecypoda cf. Pisidium 178 

Pelecypoda Sphaeriidae or Corbicula (imm.) 44 800 Gastropoda Hydrobiidae 89 89 

Gastropoda Planorbidae 44

Nematoda Nematoda 4577 3111 800 2622 20

Nematoda Mermithidae Platyhelmeths microturbellarians 178 400 133 311 

1 Definition of acronyms: 

e.i. = early instarimm. = immaturecf. = similar to (compares)

2 In April 2006, Ball Bay was more centrally sampled approximately 1 km south of its entrace (EBB)

18-Apr-06 
Table 9. Benthic chlorophyll and phaeophytin concentrations (in micrograms per square centimeter; n=3)

at Upper Klamath Lake, OR. 

Chl-a/

Phaeo- Phaeo+Chl-a Water-column

Chl-a stdev phytin stdev ratio stdev Chl-a1

 (μg-L-1)

18-Apr-06 5.0 1.5 5.3 2.2 0.49 0.18

31-May-06 2.5 0.5 6.4 0.6 0.28 0.04 2 9,305 Maxiumum 24 July 2006

2-Aug-06 0.8 0.2 5.1 0.1 0.14 0.03 198

2-May-07 0.6 0.3 13.6 3.1 0.04 0.01

10-Jul-07 1.0 0.2 7.0 0.9 0.12 0.02

18-Apr-06 3.9 0.7 4.0 0.7 0.50 0.07

31-May-06 5.9 1.5 8.1 1.1 0.42 0.07 7 178 Maxiumum 10 July 2006

2-Aug-06 3.2 0.8 9.0 1.1 0.26 0.03 23

2-May-07 0.5 0.3 13.8 1.5 0.03 0.02

10-Jul-07 0.6 0.2 7.3 2.3 0.07 0.00

18-Apr-06

2 5.5 0.6 5.6 0.3 0.49 0.02 *

31-May-06 3.7 0.4 4.1 1.1 0.48 0.07

2-Aug-06 1.0 0.2 14.1 2.2 0.07 0.02

2-May-07 1.0 0.2 12.6 5.3 0.08 0.04

10-Jul-07 1.7 0.5 12.7 3.6 0.12 0.01

31-May-06 3.0 0.6 3.1 0.5 0.49 0.08

2-Aug-06 0.8 0.3 4.4 0.5 0.15 0.04

2-May-07 0.4 0.1 4.9 0.4 0.08 0.02

10-Jul-07 0.6 0.1 3.7 1.1 0.16 0.07

31-May-06 1.0 0.2 3.9 0.4 0.20 0.06

2-Aug-06 1.5 0.2 5.2 1.4 0.23 0.03

2-May-07 0.5 0.1 6.3 1.2 0.07 0.03

10-Jul-07 0.7 0.4 5.3 1.2 0.12 0.06

MDL 18-Apr-06 2.1 0.8 2.8 1.7 0.46 0.23

MDT 18-Apr-06 9.6 3.0 8.8 2.9 0.52 0.06

1 Water-column chlorophyll data from USGS Oregon Water Science Center study led by T. Wood 

 (Internet access at: http://or.water.usgs.gov/projs_dir/klamath_ltmon/#Anchor-DAT-35519)

2

 Ball Bay location sampled April 18, 2006 was approximately 1 km south from EBB

EBB

MRM

SBI

HDB

WMR
20 EBB -6.0 0.90 0.75 0.018 0.11 0.08 0.55 NA NA 19 0.7 28 7.3

21 EBB -8.0 0.90 0.72 0.015 0.10 0.07 0.52 NA NA 18 0.6 27 7.1

22 EBB -10.0 0.89 0.74 0.017 0.12 0.07 0.53 NA NA 16 0.6 24 4.9

23 SBI -0.5 0.92 0.89 0.083 0.497 0.08 0.23 6.5 0.9 19 1.6 24 3.8

24 SBI -1.5 0.91 0.98 0.026 0.291 0.07 0.60 6.2 0.8 17 1.6 23 4.8

25 SBI -2.5 0.91 0.65 0.013 0.065 0.07 0.50 6.0 0.8 16 1.1 27 4.9

26 SBI -3.5 0.91 0.58 0.014 0.010 0.06 0.50 6.0 0.8 20 0.9 26 4.9

27 SBI -4.5 0.90 0.57 0.014 0.010 0.06 0.48 5.8 0.8 14 0.8 25 4.6

28 SBI -6.0 0.90 0.56 0.010 0.138 0.07 0.34 5.9 0.8 15 0.8 28 4.7

29 SBI -8.0 0.89 0.54 0.007 0.115 0.07 0.35 6.0 0.8 14 0.8 25 4.8

30 SBI -10.0 0.89 0.55 0.007 0.033 0.06 0.45 5.8 0.8 16 0.8 26 4.4

31 SBI -12.0 0.89 0.53 0.008 0.003 0.07 0.45 5.9 0.8 18 0.7 24 2.4

32 SBI -14.0 0.88 0.54 0.009 0.074 0.06 0.40 5.8 0.8 14 0.8 25 2.4

33 SBI -16.5 0.87 0.60 0.008 0.017 0.03 0.54 6.0 0.8 16 0.9 26 4.6

34 SBI -19.5 0.87 0.59 0.010 0.079 0.06 0.44 5.7 0.8 15 0.9 25 2.4

35 SBI -22.5 0.87 0.52 0.013 0.009 0.07 0.43 5.5 0.8 17 0.6 26 4.4

36 SBI -25.5 0.88 0.41 0.016 0.033 0.06 0.30 4.6 0.7 15 0.4 22 4.5

37 SBI -0.5 0.93 0.98 0.069 0.344 0.08 0.49 NA NA 16 1.5 21 2.4

38 SBI -1.5 0.92 0.72 0.022 0.139 0.07 0.49 NA NA 16 1.2 23 4.7

39 SBI -2.5 0.92 0.67 0.023 0.014 0.07 0.57 NA NA 15 1.0 26 4.5

40 SBI -3.5 0.91 0.68 0.013 0.083 0.07 0.51 NA NA 17 0.8 26 4.7

41 SBI -4.5 0.91 0.58 0.011 0.068 0.07 0.43 NA NA 14 0.8 26 4.1

42 SBI -6.0 0.90 0.56 0.011 0.029 0.06 0.45 NA NA 14 0.8 25 2.4

43 SBI -8.0 0.90 0.55 0.010 0.004 0.08 0.46 NA NA 15 0.6 24 4.6

44 SBI -10.0 0.90 0.53 0.012 0.009 0.07 0.44 NA NA 16 0.6 26 4.9

45 HDB -0.5 0.94 0.75 0.054 0.11 0.09 0.50 7.5 0.9 16 0.8 19 5.1

46 HDB -1.5 0.93 0.68 0.038 0.12 0.08 0.44 7.2 0.9 14 0.8 20 4.7

47 HDB -2.5 0.92 0.74 0.035 0.04 0.07 0.59 7.2 0.9 16 0.7 21 2.3

48 HDB -3.5 0.91 0.69 0.031 0.07 0.08 0.50 7.2 0.9 15 0.6 21 5.7

49 HDB -4.5 0.91 0.64 0.032 0.08 0.08 0.45 7.2 0.9 17 0.6 21 2.3

50 HDB -6.0 0.91 0.64 0.028 0.08 0.07 0.46 7.2 0.9 15 0.6 21 6.6

51 HDB -8.0 0.90 0.53 0.027 0.03 0.08 0.40 6.9 0.8 14 0.4 20 4.0

52 HDB -10.0 0.89 0.49 0.023 0.02 0.08 0.36 6.9 0.9 15 0.4 20 6.4

53 HDB -12.0 0.88 0.45 0.021 0.03 0.08 0.32 6.4 0.8 12 0.3 16 3.5

54 HDB -14.0 0.88 0.45 0.018 0.03 0.08 0.32 6.3 0.6 15 0.3 21 8.3

55 HDB -16.5 0.87 0.34 0.017 0.03 0.08 0.21 6.0 0.8 13 0.2 19 8.6

56 HDB -19.5 0.89 0.40 0.016 0.03 0.07 0.28 6.1 0.8 12 0.3 16 7.3

57 HDB -22.5 0.91 0.34 0.013 0.03 0.07 0.23 5.2 0.6 12 0.2 17 4.7

58 HDB -25.5 0.91 0.28 0.012 0.03 0.05 0.18 4.7 0.5 11 0.2 18 7.3

59 HDB -0.5 0.94 0.82 0.079 0.09 0.08 0.57 NA NA 13 0.8 19 5.4

60 HDB -1.5 0.92 0.68 0.035 0.03 0.07 0.54 NA NA 14 0.7 20 7.1

61 HDB -2.5 0.92 0.66 0.033 0.03 0.07 0.53 NA NA 15 0.4 22 7.6

62 HDB -3.5 0.91 0.65 0.033 0.08 0.08 0.46 NA NA 17 0.5 24 2.2

63 HDB -4.5 0.91 0.63 0.032 0.01 0.08 0.51 NA NA 14 0.5 20 4.2

64 HDB -6.0 0.91 0.54 0.028 0.00 0.08 0.43 NA NA 12 0.4 17 4.3

65 HDB -8.0 0.90 0.49 0.021 0.00 0.07 0.39 NA NA 14 0.3 18 6.6

66 HDB -10.0 0.89 0.46 0.020 0.03 0.07 0.34 NA NA 15 0.3 20 4.4

67 MDL -0.5 0.90 0.63 0.053 0.00 0.08 0.50 4.8 0.6 18 0.1 49 20.6

68 MDL -1.5 0.88 0.48 0.021 0.00 0.07 0.40 4.4 0.5 18 0.5 50 18.8

69 MDL -2.5 0.89 0.37 0.012 0.00 0.07 0.29 4.2 0.5 15 0.5 34 17.1

70 MDL -3.5 0.88 0.41 0.011 0.00 0.07 0.33 4.0 0.5 15 0.4 33 14.4

71 MDL -4.5 0.88 0.35 0.013 0.00 0.06 0.28 4.3 0.6 13 0.1 29 9.4

72 MDL -6.0 0.89 0.29 0.008 0.00 0.07 0.21 3.6 0.5 12 0.3 28 7.8

73 MDL -8.0 0.87 0.23 0.005 0.00 0.07 0.15 3.7 0.5 21 0.3 24 5.3

74 MDL -10.0 0.91 0.23 0.006 0.00 0.06 0.17 3.7 0.5 10 0.2 23 5.2

75 MDL -12.0 0.91 0.28 0.009 0.00 0.07 0.21 3.9 0.5 14 0.2 25 6.6

76 MDL -14.0 0.89 0.28 0.009 0.00 0.07 0.20 3.4 0.5 11 0.2 22 5.5

77 MDL -16.5 0.86 0.27 0.008 0.00 0.06 0.20 3.6 0.5 11 0.3 26 8.5

78 MDL -19.5 0.88 0.25 0.010 0.00 0.06 0.18 3.8 0.5 8 0.3 16 2.7

79 MDL -22.5 0.86 0.23 0.010 0.00 0.07 0.15 3.5 0.5 14 0.3 29 7.9

80 MDL -25.5 0.86 0.39 0.011 0.00 0.06 0.32 3.4 0.4 13 0.3 27 7.7

81 MDL -0.5 0.91 0.43 0.048 0.00 0.08 0.30 NA NA 14 0.7 37 12.2

82 MDL -1.5 0.90 0.49 0.028 0.00 0.07 0.40 NA NA 14 0.6 39 14.3

83 MDL -2.5 0.89 0.33 0.015 0.00 0.07 0.25 NA NA 13 0.5 32 11.2

84 MDL -3.5 0.89 0.37 0.010 0.00 0.07 0.29 NA NA 13 0.4 31 9.8

85 MDL -4.5 0.89 0.30 0.009 0.00 0.07 0.22 NA NA 12 0.3 32 8.5

86 MDL -6.0 0.89 0.31 0.009 0.00 0.06 0.24 NA NA 12 0.3 29 8.0

87 MDL -8.0 0.90 0.43 0.011 0.00 0.08 0.34 NA NA 12 0.3 29 6.9

88 MDL -10.0 na 0.30 0.010 0.00 0.07 0.22 NA NA 11 0.3 24 6.4

1

 "NA" indicates that samples were not analyzed for this constituent. 
93 EBB 

4.5 0.91 0.98 0.029 0.00 0.05 0.90 8.1 0.9 16 0.6 28 6.8

94 EBB -6.0 0.90 0.89 0.030 0.00 0.06 0.80 8.0 0.9 17 0.5 28 5.9

95 EBB -8.0 0.90 0.93 0.029 0.00 0.05 0.85 8.1 0.8 16 0.5 23 6.3

96 EBB -10.0 0.89 0.98 0.031 0.00 0.05 0.90 7.8 0.9 16 0.5 27 6.4

97 EBB -12.0 0.89 0.86 0.026 0.00 0.05 0.79 7.4 0.7 14 0.4 38 13.9

98 EBB -14.0 0.88 0.76 0.027 0.00 0.05 0.68 7.6 0.8 15 0.4 25 5.8

99 EBB -16.5 0.87 0.63 0.025 0.00 0.05 0.55 7.7 0.8 21 0.4 28 6.8

100 EBB -19.5 0.87 0.69 0.024 0.00 0.05 0.61 7.1 0.7 23 0.4 28 6.9

101 EBB -22.5 0.88 0.68 0.015 0.00 0.05 0.62 7.0 0.8 13 0.2 22 5.9

102 EBB -25.5 0.90 1.07 0.014 0.00 0.05 1.00 6.9 0.8 67 0.1 28 9.1

103 EBB -0.5 0.93 0.76 0.075 0.15 0.06 0.48 NA1 NA 16 0.7 26 7.6

104 EBB -1.5 0.91 0.83 0.041 0.08 0.05 0.66 NA NA 17 0.6 29 8.0

105 EBB -2.5 0.91 0.77 0.028 0.07 0.05 0.62 NA NA 17 0.7 30 8.1

106 EBB -3.5 0.91 0.77 0.030 0.03 0.05 0.65 NA NA 15 0.5 2 0.5

107 EBB -4.5 0.91 0.78 0.028 0.04 0.05 0.66 NA NA 31 0.4 53 13.2

108 EBB -6.0 0.91 0.78 0.029 0.05 0.05 0.65 NA NA 16 0.5 27 7.7

109 EBB -8.0 0.90 0.90 0.029 0.04 0.05 0.78 NA NA 15 0.4 21 5.9

110 EBB -10.0 0.90 0.76 0.032 0.05 0.05 0.62 NA NA 59 0.4 25 6.8

111 SBI -0.5 0.93 0.62 0.092 0.24 0.05 0.25 6.0 0.6 15 1.2 22 7.0

112 SBI -1.5 0.92 0.61 0.035 0.08 0.04 0.46 6.3 0.7 13 1.2 20 5.5

113 SBI -2.5 0.90 0.55 0.023 0.02 0.04 0.47 5.9 0.6 17 1.1 21 5.8

114 SBI -3.5 0.90 0.61 0.019 0.04 0.04 0.52 5.9 0.6 13 1.0 20 8.4

115 SBI -4.5 0.90 0.58 0.018 0.00 0.05 0.51 5.6 0.6 14 1.2 24 7.2

116 SBI -6.0 0.89 0.53 0.021 0.07 0.05 0.40 6.0 0.6 13 0.6 25 7.6

117 SBI -8.0 0.89 0.54 0.018 0.00 0.05 0.48 5.8 0.6 13 0.5 25 7.3

118 SBI -10.0 0.88 0.50 0.014 0.00 0.05 0.44 5.8 0.6 13 0.5 20 6.2

119 SBI -12.0 0.89 0.45 0.023 0.00 0.05 0.38 5.6 0.6 14 0.4 21 0.0

120 SBI -14.0 0.88 0.49 0.019 0.00 0.05 0.43 5.0 0.5 13 0.4 20 5.4

121 SBI -16.5 0.88 0.58 0.012 0.00 0.05 0.52 5.6 0.6 13 1.0 23 5.7

122 SBI -19.5 0.87 0.49 0.018 0.00 0.05 0.42 5.0 0.5 13 0.4 23 5.8

123 SBI -22.5 0.87 0.62 0.019 0.00 0.05 0.54 5.1 0.5 14 0.4 25 6.9

124 SBI -25.5 0.88 0.55 0.016 0.00 0.04 0.49 5.1 0.5 12 0.2 22 6.0

125 SBI -0.5 0.93 0.67 0.088 0.33 0.05 0.20 NA NA 15 1.7 22 7.8

126 SBI -1.5 0.91 0.65 0.028 0.05 0.04 0.54 NA NA 14 0.8 25 9.6

127 SBI -2.5 0.91 0.64 0.025 0.01 0.05 0.56 NA NA 13 0.7 22 6.9

128 SBI -3.5 0.91 0.59 0.029 0.02 0.05 0.49 NA NA 13 0.5 21 7.5

129 SBI -4.5 0.91 0.64 0.030 0.03 na 0.58 NA NA 15 0.6 24 5.9

130 SBI -6.0 0.90 0.77 0.024 0.01 na 0.74 NA NA 13 0.4 24 7.4

131 SBI -8.0 0.90 0.72 0.031 na 0.00 0.69 NA NA 15 0.5 25 6.9

132 SBI -10.0 0.89 0.70 0.000 0.01 0.00 0.69 NA NA 14 0.5 24 8.2

133 HDB -0.5 0.94 0.72 0.102 0.14 0.04 0.44 7.2 0.9 14 0.7 24 8.7

134 HDB -1.5 0.93 0.66 0.056 0.03 0.05 0.53 7.2 0.9 14 0.4 21 15.5

135 HDB -2.5 0.93 0.76 0.060 0.00 0.04 0.66 7.1 0.9 14 0.4 24 9.2

136 HDB -3.5 0.92 0.58 0.051 0.05 0.04 0.44 7.7 0.9 14 0.3 26 11.3

137 HDB -4.5 0.92 0.51 0.049 0.09 0.04 0.32 7.6 0.9 14 0.4 24 13.3

138 HDB -6.0 0.91 0.57 0.050 0.05 0.05 0.43 6.9 0.9 0 0.3 0 0.0

139 HDB -8.0 0.90 0.45 0.039 0.03 0.07 0.31 7.2 0.9 14 0.4 22 11.3

140 HDB -10.0 0.89 0.42 0.031 0.00 0.04 0.34 6.5 0.8 13 0.3 21 8.4

141 HDB -12.0 0.89 0.44 0.025 0.00 0.04 0.38 6.7 0.8 13 0.3 21 8.5

142 HDB -14.0 0.88 0.84 0.026 0.00 0.04 0.77 6.0 0.7 14 0.2 24 9.7

143 HDB -16.5 0.88 0.59 0.021 0.00 0.06 0.51 7.3 0.9 18 0.2 24 8.4

144 HDB -19.5 0.88 0.70 0.023 0.00 0.04 0.63 5.8 0.7 15 0.1 23 7.9

145 HDB -22.5 0.90 0.75 0.013 0.00 0.04 0.70 5.4 0.7 12 0.7 19 7.3

146 HDB -25.5 0.90 0.76 0.01 0.0 0.07 0.68 4.4 0.5 12 NA 20 7.5

147 HDB -0.5 0.94 0.76 0.053 0.18 0.05 0.47 NA NA 9 0.4 18 6.8

148 HDB -1.5 0.93 0.65 0.034 0.12 0.04 0.47 NA NA 14 0.4 22 8.2

149 HDB -2.5 0.92 0.60 0.031 0.00 0.04 0.53 NA NA 13 0.3 21 7.8

150 HDB -3.5 0.92 0.68 0.029 0.02 0.04 0.59 NA NA 13 0.4 24 8.4

151 HDB -4.5 0.92 0.66 0.031 0.03 0.04 0.56 NA NA 13 0.3 21 7.6

152 HDB -6.0 0.91 0.75 0.037 0.00 0.04 0.67 NA NA 24 0.4 19 3.7

153 HDB -8.0 0.90 0.70 0.041 0.00 0.04 0.61 NA NA 14 0.3 19 5.2

154 HDB -10.0 0.90 0.44 0.030 0.00 0.05 0.36 NA NA 25 0.3 23 6.0

155 MDL -0.5 0.91 0.76 0.052 0.03 0.09 0.59 4.9 0.6 15 0.2 40 14.3

156 MDL -1.5 0.88 0.45 0.016 0.00 0.00 0.43 4.2 0.5 15 0.4 37 13.8

157 MDL -2.5 0.88 0.51 0.012 0.00 0.07 0.42 3.9 0.5 12 0.1 34 17.4

158 MDL -3.5 0.91 0.30 0.015 0.00 0.00 0.29 3.6 0.4 46 0.3 50 23.5

159 MDL -4.5 0.88 0.34 0.014 0.00 0.08 0.25 4.1 0.5 14 0.3 38 13.3

160 MDL -6.0 0.88 0.38 0.015 0.00 0.00 0.37 4.1 0.5 13 0.2 33 12.3

161 MDL -8.0 0.88 0.35 0.016 0.00 0.07 0.26 3.9 0.5 13 0.3 34 12.0

162 MDL -10.0 0.88 0.29 0.007 0.00 0.06 0.22 3.6 0.4 14 0.3 37 12.9

163 MDL -12.0 0.87 0.24 0.009 0.00 0.06 0.17 3.7 0.4 13 0.2 35 12.5

164 MDL -14.0 0.86 0.29 0.009 0.00 0.05 0.23 3.8 0.5 12 0.2 29 9.6

165 MDL -16.5 0.85 0.33 0.010 0.00 0.05 0.27 3.6 0.5 34 0.1 28 8.7

166 MDL -19.5 0.86 0.31 0.011 0.00 0.06 0.24 4.1 0.5 12 0.1 26 7.3

167 MDL -22.5 0.88 0.24 0.011 0.00 0.07 0.16 4.2 0.5 14 0.2 31 9.5

168 MDL -25.5 0.87 0.30 0.011 0.00 0.07 0.22 4.2 0.5 16 0.2 38 12.1

169 MDL -0.5 0.92 0.74 0.074 0.00 0.07 0.60 NA NA 15 0.1 30 10.0

170 MDL -1.5 0.88 0.56 0.035 0.00 0.04 0.49 NA NA 13 0.1 23 6.2

171 MDL -2.5 0.87 0.50 0.020 0.00 0.04 0.44 NA NA 12 0.1 20 5.0

172 MDL -3.5 0.88 0.49 0.017 0.06 0.07 0.34 NA NA 15 0.9 35 12.7

173 MDL -4.5 0.88 0.41 0.016 0.00 0.08 0.31 NA NA 14 0.4 39 16.4

174 MDL -6.0 0.88 0.45 0.015 0.00 0.09 0.35 NA NA 15 0.4 43 16.1

175 MDL -8.0 0.88 0.35 0.014 0.00 0.07 0.27 NA NA 15 0.2 38 13.7

176 MDL -10.0 0.88 0.30 0.011 0.00 0.07 0.22 NA NA 13 0.2 34 11.4

1

 "NA" indicates that samples were not analyzed for this constituent. 
Table 12. Precision and recovery for sediment Standard Reference Material NIST SRM 2710 Montana Soil 

NIST SRM 2710

Element

Reported 

(mg g-1)

Reported 

Stdev

Measured 

(mg g-1)

Stdev 

(n=5)

Percent 

recovery

P 1.06 0.15 1.09 0.07 103

Fe 33.8 1 32.8 2.7 97

Al 64.4 0.8 64.5 2.6 100

Ca 12.5 0.3 12.4 0.5 99