EPA 822-B-00-023

AMBIENT WATER QUALITY CRITERIA RECOMMENDATIONS

INFORMATION SUPPORTING THE DEVELOPMENT OF STATE AND TRIBAL NUTRIENT CRITERIA

FOR

WETLANDS IN NUTRIENT ECOREGION XIII

Southern Florida Coastal Plain

including all or parts of the State of:

Florida

and the authorized Tribes within the Ecoregion

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF WATER OFFICE OF SCIENCE AND TECHNOLOGY HEALTH AND ECOLOGICAL CRITERIA DIVISION

WASHINGTON, D.C.

DECEMBER 2000ii FOREWORD

This document presents EPA’s nutrient criteria for Wetlands in Nutrient Ecoregion XIII. These criteria provide EPA’s recommendations to States and authorized Tribes for use in establishing their water quality standards consistent with section 303(c) of CWA. Under section 303(c) of the CWA, States and authorized Tribes have the primary responsibility for adopting water quality standards as State or Tribal law or regulation. The standards must contain scientifically defensible water quality criteria that are protective of designated uses. EPA’s recommended section 304(a) criteria are not laws or regulations – they are guidance that States and Tribes may use as a starting point for the criteria for their water quality standards.

The term “water quality criteria” is used in two sections of the Clean Water Act, Section 304(a)(1) and Section 303(c)(2). The term has a different impact in each section. In Section 304, the term represents a scientific assessment of ecological and human health effects that EPA recommends to States and authorized Tribes for establishing water quality standards that ultimately provide a basis for controlling discharges or releases of pollutants or related parameters. Ambient water quality criteria associated with specific waterbody uses when adopted as State or Tribal water quality standards under Section 303 define the level of a pollutant (or, in the case of nutrients, a condition) necessary to protect designated uses in ambient waters. Quantified water quality criteria contained within State or Tribal water quality standards are essential to a water quality-based approach to pollution control. Whether expressed as numeric criteria or quantified translations of narrative criteria within State or Tribal water quality standards, quantified criteria serve as a critical basis for assessing attainment of designated uses and measuring progress toward meeting the water quality goals of the Clean Water Act.

EPA is developing section 304(a) water quality criteria for nutrients because States and Tribes consistently identify excessive levels of nutrients are a major reason why as much as half of the surface waters surveyed in this country do not meet water quality objectives, such as full support of aquatic life. EPA expects to develop nutrient criteria that cover four major types of waterbodies – lakes and reservoirs, rivers and streams, estuarine and coastal areas, and wetlands – across fourteen major ecoregions of the United States. EPA’s section 304(a) criteria are intended to provide for the protection and propagation of aquatic life and recreation. To support the development of nutrient criteria, EPA is publishing Technical Guidance Manuals that describe a process for assessing nutrient conditions in the four waterbody types.

EPA’s section 304(a) water quality criteria for nutrients provide numeric water quality criteria, as well as procedures by which to translate narrative criteria within State or Tribal water quality standards. In the case of nutrients, EPA section 304(a) criteria establish values for causal variables (e.g., total nitrogen and total phosphorus) and response variables (e.g., turbidity and chlorophyll a ). EPA believes that State and Tribal water quality standards need to include quantified endpoints for causal and response variables to provide sufficient protection of uses and to maintain downstream uses. These quantified endpoints will most often be expressed as numeric water quality criteria or as procedures to translate a State or Tribal narrative criterion into a quantified endpoint.

EPA will work with States and authorized Tribes as they adopt water quality criteria for nutrients into their water quality standards. EPA recognizes that States and authorized Tribes require flexibility in adopting numeric nutrient criteria into State and Tribal water quality standards. States and authorized Tribes have several options available to them. EPA recommends the following approaches, in order of preference:iii

(1) Wherever possible, develop nutrient criteria that fully reflect localized conditions and protect specific designated uses using the process described in EPA’s Technical Guidance Manuals for nutrient criteria development. Such criteria may be expressed either as numeric criteria or as procedures to translate a State or Tribal narrative criterion into a quantified endpoint in State or Tribal water quality standards.

(2) Adopt EPA’s section 304(a) water quality criteria for nutrients, either as numeric criteria or as procedures to translate a State or Tribal narrative nutrient criterion into a quantified endpoint.

(3) Develop nutrient criteria protective of designated uses using other scientifically defensible methods and appropriate water quality data.

Geoffrey H. Grubbs, Director Office of Science and Technologyiv DISCLAIMER

This document provides technical guidance and recommendations to States, authorized Tribes, and other authorized jurisdictions to develop water quality criteria and water quality standards under the Clean Water Act (CWA) to protect against the adverse effects of nutrient overenrichment. Under the CWA, States and authorized Tribes are to establish water quality criteria to protect designated uses. State and Tribal decision-makers retain the discretion to adopt approaches on a case-by-case basis that differ from this guidance when appropriate and scientifically defensible. While this document contains EPA’s scientific recommendations regarding ambient concentrations of nutrients that protect aquatic resource quality, it does not substitute for the CWA or EPA regulations; nor is it a regulation itself. Thus it cannot impose legally binding requirements on EPA, States, authorized Tribes, or the regulated community, and it might not apply to a particular situation or circumstance. EPA may change this guidance in the future.v EXECUTIVE SUMMARY

Nutrient Program Goals

EPA developed the National Strategy for the Development of Regional Nutrient Criteria (National Strategy) in June 1998. The strategy presents EPA = s intentions to develop technical guidance manuals for four types of waters (lakes and reservoirs, rivers and streams, estuaries and coastal waters, and wetlands) and produce section 304(a) criteria for specific nutrient ecoregions by the end of 2000. In addition, the Agency formed Regional Technical Assistance Groups (RTAGs) which include State and Tribal representatives working to develop more refined and more localized nutrient criteria based on approaches described in the waterbody guidance manuals. This document presents EPA = s current recommended criteria for total phosphorus for wetlands in Nutrient Ecoregion XIII - Southern Florida Coastal Plain which were derived using peer-reviewed publications of research conducted in the Everglades and the findings and information associated with the EPA approval of the Miccosukee Tribe of Indians of Florida standard for phosphorus for the Federal Reservation within the Everglades.

EPA’s ecoregional nutrient criteria are intended to address cultural eutrophication – the adverse effects of excess inputs of nutrients. The criteria are empirically derived to represent conditions of surface waters that are minimally impacted by human activities and are protective of aquatic life and recreational uses. The information contained in this document represent starting points for States and Tribes to develop (with assistance from EPA) more refined nutrient criteria.

In developing these criteria recommendations, EPA followed a process which included, to the extent they were readily available, the following elements critical to criterion derivation:

! Historical and recent nutrient data in Nutrient Ecoregion XIII. Historical and recent data used in the development of the nutrient criteria for this ecoregion include information from more than 300 scientific publications and reports were reviewed and summarized; the Everglades Interim Report (1999) published by the South Florida Water Management District; Phosphorus Biogeochemistry in Subtropical Ecosystems (1999) a compilation of papers from a symposium, and a comparison of soil phosphorus concentrations in 1990 and 1998 by DeBusk et al . (1994) and DeBusk et al

. (in press).



### ! Reference sites/reference conditions in Nutrient Ecoregion XIII. Reference conditions presented in this document were summarized from peer-reviewed literature and the primary source documents listed above. The water column phosphorus number for reference condition and criteria recommendations is based on long-term (at least three months) average values. Hydrologic variability can result in variable concentrations of water column total phosphorus, therefore, a long-term or rolling average, or geometric mean (as required by the Everglades Forever Act; Section 373.4592 Florida Statutes) is most appropriate to identify reference conditions and evaluate excursions from numeric criteria in this system. In developing reference conditions, the natural, seasonal/annual hydrologic variability should be considered. Periphyton reference condition and criterion recommendations are based on relative species abundance, which has been found to be an integrative measure of nutrient condition. for the previous three months. The oligotrophic Everglades marsh system contains a mosaic of wetland community types, such as sloughs, wet prairies and sawgrass marshes, all of which are adapted to low nutrient conditions. The mosaic character of the South Florida Coastal Plain Nutrient Ecoregion, which provides a diverse array of habitats for animals, is an important defining characteristic of the Everglades and was recognized in developing reference conditions for the ecoregion. States and Tribes are urged to determine their own reference sites for wetlands within the ecoregion at different geographic scales and tovi

compare them to EPA’s reference conditions.



### ! Models employed for prediction or validation. Several models have been developed for the Everglades. Summaries and detailed descriptions of models developed for the Everglades can be found in McCormick et al

. (1999) and Phosphorus Biogeochemistry in Subtropical Ecosystems (1999), respectively. States and Tribes are encouraged to identify and apply appropriate models to support nutrient criteria development.



### ! RTAG expert review and consensus. EPA recommends that when States and Tribes prepare their nutrient criteria, they obtain the expert review and consent of the RTAG.



### ! Downstream effects of criteria. EPA encourages the RTAG to assess the potential effects of the proposed criteria on downstream water quality and uses.

A summary of reference conditions for the Aggregate nutrient ecoregion for water column TP and vegetation are presented below. These were chosen because they constitute early warning indicators of eutrophication within the Everglades systems.

BASED ON LITERATURE VALUES

Aggregate Ecoregion XIIISouthern Florida Coastal Plain Reference Conditions

Total Water Column Phosphorus (μg/L) 10

Periphyton No significant change in relative species abundance

EPA also recommends that States and Tribes develop reference conditions and criteria for soil phosphorus levels since it is considered a necessary indicator of eutrophication and phosphorus condition within the Everglades. Studies have indicated that 300-600 mg P/kg soil is the preferred range for organic soils. However, these same levels may not be appropriate for mineral soils in some regions of the Everglades.vii NOTICE OF DOCUMENT AVAILABILITY

This document is available electronically to the public through the INTERNET at: ( http://www.epa.gov/OST/standards/nutrient.html ). Requests for hard copies of the document should be made to EPA’s National Service Center for Environmental Publications (NSCEP), 11029 Kenwood Road, Cincinnati, OH 45242 or (513) 489-8190, or toll free (800) 490-9198. Please refer to EPA document number EPA-822-B-00-023

.viii ACKNOWLEDGMENTS

The authors thankfully acknowledge the contributions of the following State and Federal reviewers: Amanda Parker (Warnell School of Forest Resources, University of Georgia); EPA Region 4; the State of Florida; the Tribes within the Ecoregion; EPA Headquarters personnel from the Office of Wetlands, Oceans and Watersheds, Office of Wastewater Management, Office of General Counsel, Office of Research and Development, and the Office of Science and Technology. EPA also acknowledges the external peer review efforts of Paul McCormick (The Nature Conservancy), Ramesh Reddy (University of Florida), and Jan Stevenson (Michigan State University).ix LISTS OF FIGURES AND TABLES

Figures

Figure 1 Aggregate Ecoregion XIII

.............................. 6

Figure 2 Aggregate ecoregion XIII with level III ecoregions shown

..... 7

Tables

Table 1 Reference conditions for Aggregate Ecoregion XIII– Southern Florida Coastal Plain

................................. 11x TABLE OF CONTENTS

Foreword

................................................................. ii

Disclaimer

............................................................... iv

Executive Summary

.......................................................... v

Notice of Document Availability

............................................... vii

Acknowledgments

........................................................ viii

List of Tables and Figures

.................................................... ix

Table of Contents

........................................................... x

1.0 Introduction

............................................................ 1

2.0 Best Use of this Information

............................................... 3

3.0 Area Covered by This Document (waterbody type and ecoregion)

.................. 5 3.1 Description of Aggregate Ecoregion XIII --Southern Florida Coastal Plain

.... 5 3.2 Geographical Boundaries of Aggregate Ecoregion XIII

................... 6 3.3 Level III Ecoregions within Aggregate Ecoregion XIII

................... 6

4.0 Data Review for Wetlands in Aggregate Ecoregion XIII

.......................... 7 4.1 Data Sources

................................................... 7 4.2 Historical Data from Aggregate Ecoregion XIII (TP, Soil P, and Vegetation)

. . 8 4.3 Data for all Wetlands within Aggregate Ecoregion XIII ..

.................. 9 4.4 Classification of Wetland Type

...................................... 9

5.0 Reference Sites and Conditions for Wetlands in Aggregate Ecoregion XIII

............ 9

6.0 Models Used to Predict or Verify Response Parameters

.......................... 11

7.0 Framework for Refining Recommended Nutrient Criteria for Wetlands in Aggregate Ecoregion XIII

................................................. 11 7.1 Example Worksheet for Developing Aggregate Ecoregion and Subecoregion Nutrient Criteria

............................................... 12 7.2 Setting Seasonal Criteria

......................................... 13 7.3 Site-specific Criteria Development

.................................. 13

8.0 Literature Cited

........................................................ 13

9.0 Appendices

........................................................... 141

1.0 INTRODUCTION

Background

Nutrients are essential to the health and diversity of our surface waters. However, in excessive amounts, nutrients cause hypereutrophication, which results in overgrowth of plant life and decline of the biological community. Excessive nutrients can also result in potential human health risks, such as the growth of harmful algal blooms

- most recently manifested in the Pfiesteria outbreaks of the Gulf and East Coasts. Chronic nutrient overenrichment of a waterbody can lead to the following consequences: low dissolved oxygen, fish kills, algal blooms, overabundance of macrophytes, likely increased sediment accumulation rates, and species shifts of both flora and fauna.

Historically, National Water Quality Inventories have repeatedly shown that nutrients are a major cause of ambient water quality use impairments. EPA’s 1996 National Water Quality Inventory report identifies excessive nutrients as the leading cause of impairment in lakes and the second leading cause of impairment in rivers (behind siltation). In addition, nutrients were the second leading cause of impairments reported by the States in their 1998 lists of impaired waters. Where use impairment is documented, nutrients contribute roughly 25-50% of the impairment nationally. The Clean Water Act establishes a national goal to achieve, wherever attainable, water quality which provides for the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water. In adopting water quality standards, States and Tribes designate uses for their waters in consideration of the Clean Water Act goals, and establish water quality criteria that contain sufficient parameters to protect those uses. To date, EPA has not published information and recommendations under section 304(a) for nutrients to assist States and Tribes in establishing numeric nutrient criteria to protect uses when adopting water quality standards.

In 1995, EPA gathered a set of national experts and asked the experts how to best deal with the national nutrient problem. The experts recommended that the Agency not develop single criteria values for phosphorus or nitrogen applicable to all water bodies and regions of the country. Rather, the experts recommended that EPA put a premium on regionalization, develop guidance (assessment tools and control measures) for specific waterbodies and ecological regions across the country, and use reference conditions (conditions that reflect pristine or minimally impacted waters) as a basis for developing nutrient criteria.

With these suggestions as starting points, EPA developed the National Strategy for the Development of Regional Nutrient Criteria (National Strategy), published in June 1998. This strategy presented EPA’s intentions to develop technical guidance manuals for four types of waters (lakes and reservoirs, rivers and streams, estuaries and coastal waters, and wetlands) and, thereafter, to publish section 304(a) criteria recommendations for specific nutrient ecoregions. Technical guidance manuals for lakes/reservoirs and rivers/streams were published in April 2000 and July 2000, respectively. The technical guidance manual for estuaries/coastal waters will be published in spring 2000 and the draft wetlands technical guidance manual will be published by December 2001. Each manual presents EPA’s recommended approach for developing nutrient criteria values for a specific waterbody type. In addition, EPA is committed to working with States and Tribes to develop more refined and more localized nutrient criteria based on approaches described in the waterbody guidance manuals and this document.

Overview of the Nutrient Criteria Development Process

For each Nutrient Ecoregion, EPA developed a set of recommendations for two causal variables (total nitrogen and total phosphorus) and two early indicator response variables (chlorophyll a and some measure of turbidity). Other indicators such as dissolved oxygen and macrophyte growth or speciation, and other fauna and flora changes are also deemed useful. However, the first four are considered to be the best suited for protecting designated uses. This2

basic set of indicators clearly must be modified for wetlands to accommodate the complexity of these aquatic environments. The parameters of concern for the Southern Florida Coastal Plain are water column total phosphorus (TP) concentration; soil phosphorus concentration, and change in vegetation communities. Parameters of concern for the Everglades will also be used in other wetland systems, if appropriate.

The technical guidance manuals describe a process for developing nutrient criteria that involves consideration of five factors. The first of these is the Regional Technical Assistance Group (RTAG), which is a body of qualified regional specialists able to objectively evaluate all of the available evidence and select the value(s) appropriate to nutrient control in the water bodies of

concern. These specialists may come from such disciplines as limnology, biology, natural resources management-- especially water resource management, chemistry, and ecology. The RTAG evaluates and recommends appropriate classification techniques for criteria determ ination, usually physical within an ecoregional construct.

The second factor is the historical information available to establish a perspective of the

resource base. This is usually data and anecdotal information available within the past ten to twentyfive years. This information gives evidence about the background and enrichment trend of the

resource.

The third factor is the present reference condition. A selection of reference sites chosen to represent the least culturally impacted waters of the class existing at the present time. The data from these sites are combined a nd a value from the distribution of these observations is selected to represent the reference condition, or best attainable, most natural condition of the resource base at this time.

A fourth factor often employed is theoretical or empirical models of the historical and reference condition data to better understand the condition of the resource. It is recognized that, distinct from ambient monitoring or empirical efforts, field and laboratory experiments can elucidate specific processes and establish cause and effect. These studies (such as field nutrient dosing studies,

mesocosm studies, or lab o ratory mesocosm or microcosm experiments) can facilitate causal interpretation of data. (Lean, et al ., 1992; Hopkinson, et la. , 1998).

The RTAG comprehensively evaluates the other three elements to propose a candidate criterion (initially one each for TP, TN, chl a , and some measure of turbidity).

The last and final element of the criteria development process is the assessment by the RTAG of the likely downstream effects of the criterion. Will there be a negative, positive, or neutral effect

on the downstream waterbody? If the RTAG judges that a negative effect is likely, then the proposed State/Tribal water quality criteria should be revised to amelior ate the potential for any adverse downstream effects.

While States and authorized Tribes would not necessarily need to incorporate all five elements into their water quality criteria setting process (e.g., modeling may be significant in only some i nstances), the best assurance of a representative and effective criterion for nutrient mana gement decision making is the balanced incorporation of all five elements, or at least all elements except modeling.

Because some parts of the country have naturally higher soil and parent material enrichment, and different pre cipitation regimes, the application of the criterion development process has to be

a djusted by region. Therefore, an ecoregional approach was chosen to develop nutrient criteria appropriate to each of the different geographical and climatological areas of the country. Initially, the continental U.S. was divided into 14 separate ecoregions of similar geographical characteristics. Ecoregions are defined as regions of relative homogeneity in ecological systems; they depict areas within which the mosaic of ecosystem component s (biotic and abiotic as well as terrestrial and3

aquatic) is different than adjacent areas in a holistic sense. Geographic phenomena such as soils, vegetation, climate, geology, land cover, and physiology that are associated with spatial differences in the quantity and quality of ecosystem components are relatively similar within each ecoregion.

The Nutrient ecoregions are aggregates of U.S. EPA = s hierarchal level III ecoregions (Omernik, 1995, 1998). As such, they are more generalized and less defined than level III ecoregions. EPA determined that setting ecoregional criter ia for the large scale aggregates is not without its drawbacks

- variability is high due to the lumping of many waterbody classes, seasons, and

years worth of mu ltipurpose data over a large geographic area. For these reasons, the Agency recommends that States and Tribes develop nutrient criteria at the level III ecoregional scale and at the waterbody class scale where those data are readily available. Data analyses and recommendations on both the large aggregate ecoregion scale as well as more refined scales (level III ecoregions and waterbody classes), where data were available to make such assessments, are present ed for comparison purposes and completeness of analysis.

Relationship of Nutrient Criteria to Biological Criteria

Biological criteria are quantitative expressions of the desired condition of the aquatic community. Such criteria can be based on an aggregation of data from sites that represent the leastimpacted and attainable condition for a particular waterbody type in an ecoregion, subecoregion, or watershed. EPA’s nutrient criteria recommendations and biological criteria recommendations have

many similaritie s in the basic approach to their development and data requirements. Both are empirically derived from statistical analysis of field collected data and expert evaluation of current reference conditions and historical inform ation. Both utilize direct measurements from the environment to integrate the effects of complex processes that vary according to type and location of waterbody. The resulting criteria recommendations, in both cases, are efficient and holistic indicators of water quality necessary to protect uses.

States and authorized Tribes can develop and apply nutrient criteria and biological criteria in tandem, with each providing important and useful information to interpret both the nutrient enrichment levels and the biological condition of sampled waterbodies. For example, using the same reference sites for both types of criteria can lead to efficiencies in both sample design and data analysis. In one effort, environmental managers can obtain information to support assessment of biological and nutrient condition, either through evaluating existing data sets or through designing and conducting a common sampling program. The traditional biological criteria variables of benthic invertebrate and fish sampling can be readily incorporated to supplement a nutrient assessment. To demonstrate the effectiveness of this tandem approach, EPA has in itiated pilot projects in both freshwater and marine environments to investigate the relationship between nutrient overenrichment and apparent declines in diversity indices of benthic invertebrates and fish.

2.0 BEST USE OF THIS INFORMATION

EPA recommendations published under section 304(a) of the CWA serve several purposes, including providing guidance to States and Tribes in adopting water quality standards for nutrients that ultimately provide a basis for controlling di scharges or releases of pollutants. The recommendations also provide guidance to EPA when promulgating Federal water quality standards und er section 303(c) when such action is necessary. Other uses include identification of overenrichment problems, management planning, project evaluation, and determination of status and trends of water resources.

State water quality inventories and listings of impaired waters consistently ran k nutrient overenrichment as a top contributor to use impairments. EPA’s water quality standards regulations at 40 CFR §131.11(a) require States and Tribes to adopt criteria that contain sufficient parameters and constituents to protect the designated uses of their waters. In addition, States and Tribes need quantifiable targets for nutrients in their standards to assess attainment of uses, develop water quality-4

based permit limits and source control plans, and esta blish targets for total maximum daily loads (TMDLs).

EPA expects States and Tribes to address nutrient overenrichment in their water quality standards, and to build on existing State and Tribal initiated efforts where possible. States and Tribes

can address n u trient overenrichment through establishment of numerical criteria or through use of

new or existing narrative criteria statements (e.g., free from excess nutrients that cause or contribute

to undesirable or nuisance aquatic life or produce adverse physiological response in humans, animals,

or plants). In the case of narrative criteria, EPA expects that States and Tribes establish procedures to quantitatively translate these statements for both assessment and source control purposes.

The intent of developing ecoregional nutrient criteria is to represent conditions of surface waters that are minimally impacted by human activities and thus protect against the adverse effects of nutrient overenrichment from cultural eutrophication. EPA’s recommended process for developing such criteria includes physical classification of waterbodies, determinatio n of current reference conditions, evaluation of historical data and other information (such as published literature), use of models to s imulate physical and ecological processes or determine empirical relationships among causal and response variables (if necessary), expert judgement, and evaluation of downstream effects.
To the extent allowed by the information available, EPA has used elements of this process to produce the information contained in this document. The values for both causal (total nitrogen, total phosphorus) and biological and physical response (chlorophyll a , turbidity) variables represent a set of starting points for States and Tribes to use in establishing their own criteria in standards to protect

uses.

In its water quality standards regulations, EPA recommends that States and Tribes establish numerical criteria based on section 304(a) guidance, section 304(a) guidance modified to reflect sitespecific conditions, or other scient ifically defensible methods. For many pollutants, such as toxic chemicals, EPA expects that section 304(a) guidance will provide an appropriate level of protection without further modification in most cases. EPA has also published methods for modifying 304(a) criteria on a site-specific basis, such as the water effect ratio, where site-specific conditions warrant modification to achieve the intended level of protection. For nutrients, however, EPA expects that, in most cases, it will be necessary for States and authorized Tribes to identify with greater precision the nutrient levels that protect aquatic life and recreational uses. This can be achieved through development of criteria modified to reflect conditions at a smaller geographic scale than an ecoregion such as a subecoregion, the State or Tribe level, or specific class of waterbodies. Criteria refinement

can occur by grouping data or performing data analyses at these smaller geographic scales. Refinement can also occur through further consideration of other elements of criteria development, such as published literature or models.

The values presented in this document generally represent nutrient levels that protect against the adverse effects of nutrient overenrichment and are based on information available to the Agency

at the time of this publication. However, States and Tribes should critically evaluate this information in light of the specific designated uses that need to be protected. For example, more sensitive uses

ma y require more stringent values as criteria to ensure adequate protection. On the other hand, overly stringent levels of protection against the adverse effects of cultural eutrophication may actually fall below levels that represent the natural load of nutrients for certain waterbodies. In cases such as these, the level of nutrients specified may not be sufficient to support a produ ctive fishery. In the criteria derivation process, it is important to distinguish between the natural load associated with a specific waterbody and current reference conditions, using h istorical data and expert judgement. These elements of the nutrient criteria derivation process are best addressed by States and Tribes with

access to information and local expertise. Therefore, EPA strongly encourages States and Tribes to

use the information contained in this document and to develop more refined criteria according to the methods described in EPA’s technical guidance manuals for specific waterbody types.

To assist in the process of further refinement of nutrient criteria, EPA has established ten5

Regional Technical Advisory Groups (experts from EPA Regional Offices and States/Tribes). In the

process of refining criteria, States and authorized Tribes need to provide documentation of data and analyses, along with a defensible rationale, for any new or revised nutrient criteria they submit to EPA for review and approval. As part of EPA’s review of State and Tribal standards, EPA intends to seek assurance from the RTAG that proposed criteria are sufficient to protect uses.

In the process of using the information and recommendations contained in this document, as well a s additional information, to develop numerical criteria or procedures to translate narrative criteria, EPA encourages States and Tribes to:

C Address both chemi cal causal variables and early indicator response variables. Causal variables are necessary to provide sufficient protection of uses before impairment occurs and

to maintain downstream uses. Early response variables are necessary to provide warning signs of possible impairment and to integrate the effects of variable and po tentially unmeasured nutrient loads.

C Include variables that can be measured to determine if standards are met, and variables that can be related to the ultimate sources of excess nutrients.

C Identify appro priate periods of duration (i.e., how long) and frequency (i.e., how often) of

occurrence in addition to magnitude (i.e., how much). EPA does not recommend identifying nutrient concentrations that must be met at all times, rather a seasonal or annual averaging

p eriod (e.g.,based on weekly measurements) is considered appropriate. However, these seasonal or annual central tendency measures (i.e., geometric mean or median) should apply each season or each year, except under the most extraordinary of conditions (e.g., a 100 year flood).

3.0 AREA COVERED BY THIS DOCUMENT

The following sections provide a general description of the aggregate ec oregion and its geographical boundaries. A descriptions of the level III ecoregion contained within the aggregate ecoregion is also provided.

3.1 Description of Aggregate Ecoregion XIII

– Southern Florida Coastal Plain

The Southern Florida Coastal Plain is nearly level and subtropical to tropical (U.S. EPA, 2000). It is characterized by wildlife-rich fresh water marshes, wet prairies, sloughs, swamps, and coastal wetlands; only about 10% is used as cropland. Canals, ditches, and broad, poorly-defined stream channels are common. Lakes are generally rare but one large, shallow, regulated lake is found in the region, Lake Okeechobee; it links the waters of the Kissimmee Basin to the Everglades. Elevations are low and range from sea level to less than 50 feet; only hummocks, limestone ridges, beach ridges, and dunes relieve the flatness of the region. Poorly- and very poorly-drained, organic soils (peat and muck) are common and overlie carbonate-rich bedrock. Much of the Southern Florida Coastal Plain (XIII) has been set aside as parks, game refuges, water conservation areas, and Indian reservations. However, extensive areas have also been urbanized or drained for agriculture, resulting in the widespread alteration of hydrological and biological systems, depletion of peat deposits, and reduction of regional water quality. Canals draining developed areas generally have higher nutrient concentrations than those flowing through undeveloped areas. Lake Okeechobee is one of the largest lakes in the United States and has been significantly impacted by agricultural runoff. Cattle and dairy farms have contributed a large amount of phosphorus to the lake and the Everglades Agricultural Area has pumped nitrogen-rich water into the lake to control flooding. During the 1970s, lake concentrations of phosphorus and nitrogen more than doubled and bottom sediments accumulated a massive quantity of phosphorus. By the mid-1980s, large algal blooms had occurred.6

3.2 Geographic Boundaries of Aggregate Ecoregion XIII

Ecoregion XIII is small compared to the other ecoregions; encompassing only the southern quarter of Florida (Figure 1).

3.3 Level III Ecoregion Within Aggregate Ecoregion XIII

76. Southern Florida Coastal Plain

The frost-free cli mate of the Southern Florida Coastal Plain makes it distinct from other ecoregions in the conterminous United States (Figure 2). This region is characterized by flat plains with wet soils, marshland and swamp land cover with Evergl ades and palmetto prairie vegetation types. Although portions of this region are in parks, game refuges, and Indian reservations, a large part of the region has undergone extensive hydrological and biological alteration.

Figure 1. Aggregate Ecoregion XIII7

Figure 2. Aggregate Ecoregion XIII with level III ecoregion shown

4.0 DATA REVIEW FOR WETLANDS IN AGGREGATE ECOREGION XIII

The following section describes the nutrient dat a information that EPA reviewed for this Ecoregion. They include data for the causal parameters-- total water column phosphorus and soil phosphorus and the primary response variable-- periphyton- relative species abundance. These are the parameters which EPA considers essential to nutrient assessment in wetlands because the first two

are the measurements of the main causative agents of phosphorus enrichment and the response variable is the early indicator of system enrichment for the Everglades ecosystem (Ecoregion XIII).

4.1 Data Sources

Relevant scientific information used in determining the phosphorus criterion range in this document has been summarized from the EPA find ing in support of the criterion proposed for Miccosukee tribal lands in Nutrient Ecoregion XIII (EPA 1999), from the Everglades Interim Report (SFWMD 1999), from Phosphorus Bi ogeochemistry in Subtropical Ecosystems (1999), and from DeBusk et al ., 1994, and DeBusk et al ., in press.8

4.2 Historical Data from Aggregate Ecoregion XII I (water column TP, soil P and vegetation):

EPA recommends that States/Tribes assess long-term trends observed over the past 50 years. This information may be obtained from scientific literature or documentation of historical trends. To gain additional perspective on more recent trends, it is recommended that States and Tribes assess nutrient trends over the last 10 years (e.g., what do seasonal trends indicate?)

- long term trends over past 50 years.

Historical descriptions of the Everglades ecosystem are relatively scarce, and those that are available are largely descriptive and qualitative, rather than q uantitative in nature. Information on historical large-scale vegetation patterns is available, but water quality information is sparse prior to the 1970s (McCormick et al

., 1999). Phosphorus inputs to the Everglades historically came largely from atmospheric deposition. Current estimates indicate that the total phosphorus concentration in rainfall is typically less than 10 μ g/L and that total atmospheric inputs average between 22 and 36 mg TP/m 2 /yr; it is assumed that historical inputs were not greater than current estimates (McCormick et al

, 1999). Historically, the Everglades also received periodic inflows from Lake Okeechobee, but these inputs were likely small relative to atmospheric inputs. The more remote interior areas of the Everglades still exhibit the low P concentrations that once prevai led throughout the Everglades system. Measurements of soluble reactive phosphorus (SRP) and orthophosphate in some interior marsh sites in the 1970s and 1980s indicate that background concentrations of 2 to 5 ppb were not

uncommon (Scheidt 1999). More recent studies in the Everglades National Park (ENP) note the low concentrations of phosphorus in the interior sites. Scheidt, et al . (1989) summarized water quality characteristics of the ENP from 1984-1986, and found typical orthophosphate concentrations of 4 ppb in the interior marsh sites, with P concentration values from 10 to 35 times higher from sites in and around the Everglades Agricultural Area (EAA) and Lake Okeechobee.

The majority of soils data collected from the Everglades in the early 1900s were descriptive. The few soil data from the 1900s that are quantitative are summarized in McCormick et al

. (1999), and indicate that soil P concentrations near Okeechobee were much higher than those in more interior Everglades sites. Early studies found that soil P concentrations in the top 30 cm of organic soil at sites adjacent to Lake Okeechobee (in what is now the EAA) averaged (1,800 to 2,000 mg P/kg), and soil P concentrations at interior Everglades sites nea r Tamiami trail averaged (~400 mg P/kg) (McCormick et al. 1999). More recent studies of soil P have indicated an increase in surficial soil phosphorus concentrations of up to three-fold since the 1970s (Davis 1989; Reddy et al

. 1991; DeBusk et al

. 1994; Reddy et al

. 1998; DeBusk et al

., in press) in those areas receiving inflows from canals draining the EAA.

Periphyton is the most widely dist ributed plant community in the Everglades. Periphyton exhibits three growth forms in the Everglades: benthic (growing on the soil surface), epiphytic (growing attached to roote d vegetation) and floating (growing on the water surface sometimes in association with other floating vegetation such as Utricularia purpurea ) (McCormick e t al

., 1999). Periphyton mat communities are found throughout the unimpacted Everglades marsh, especially in

open water areas, sloughs and wet prairies, and are particularly well adapted to the low P conditions historically found in the Everglades ecosystem. The first visible changes caused by P enrichment are seen in the periphyton mat communities. As the P-limited areas of the Everglades are enriched, the calcareous blue-green algae and diatoms are replaced by soft-bodied green and blue-green algae, and the soft-water periphyton communities show increased relativ e abundance of pollution-tolerant species. Swift (1984) found that marsh water TP was the controlling factor regulating periphyton growth. Elevated water TP increased periphyton biomass, increased periphyton phosphorus content, and altered community species composition toward pollution-tolerant species. The continued flow of nut rient enriched waters into the Everglades from the EAA has also resulted in more profound changes in the vegetation community. Increased macrophyte growth has decreased periphyton productivit y due to reduced light availability, and has caused a change in macrophyte community9

composition. The historically dominant marsh macrophyte, C ladium jamaicense

, is being displaced with the high P-adapted species, Typha domingensi s , in those areas enriched by EAA outflows (McCormick et al . 1999; Bechtel et al . 1999; DeBusk, et al ., in press). This also includes the loss of open water wet prairies plant communities.

-trends over the last 10 years

Recent trends in the Everglades reflect the continued enrichment of the Everglades. Phosphorus concentrations in those areas closest to the Everglades Agricultural Area (EAA) outflows show the greatest levels of enrichment in both the water column and soil phosphorus concentrations. The increasing loss of native periphyton, and continued spread of Typha latifolia into the more interior areas of the Everglades further support the conclusion that nutrient enrichment is affecting the Everglades ecosystem.

Water column total phosphorus concentrations in remote interior sites currently a verage b etween 4 and 10 μg/L (McCormick et al

. 1999); contemporary measurements of soil porew ater concentrations are consistently below 50 μg/L soluble reactive phosphorus (SRP), and are often at

or below 4 μg/L, and total phosphorus concentrations in surface soils range betw een 200 and 500mg/kg (McCormick et al

. 1999). Chronic inputs of P from the EAA has lead to increased P in the water and soil in areas receiving inflows from canals draining the EAA, and a forward moving front of P-enriched surficial soil (McCormick et al . 1999; DeBusk et al , in press).

Water column phosphorus concentrations within the Everglades fluctuate naturally with water conditions. Marsh phosphorus concentrations have been shown to vary with water depth, with higher concentration excursions occurring during periods of low water or marsh drying (McCormick, et al . 1999). McCormick et al . (1999) summarized the impact of increased P loading to the Everglades on microbial and biogeochemical processes. P loading has been shown to affect the quality and quantity of organic matter, rates of nutrient accumulation, microbial biomass and community composition, and biogeochemical cycling. Moreover, P enrichment has been shown to initiate a series of effects on the cycling of carbon and nitrogen, as well as a shift in the system from an aerobic environment where oxygen is readily available to an anaerobic environment where oxygen is lacking.

4.3 Data for all Wetlands Within Aggregate Ecoregion XIII

The Everglades predominate in Ecoregion XIII. The information presented in this document is from studies performed in the Everglades.

4.4. Classification of Wetland Type:

The Everglades ecosystem is a large, unique wetland mosaic in the tropical and sub-tropical southern peninsula of Florida. Classification of the Everglades system into sub-types based on chemical, phys ical and biological differences can help decrease variability in monitoring data. In addition, nutrient gradients are evident in the Everglades system, and comparisons of data along the spatial gradient may be of use in further refining nutrient criteria for this system.

5.0 REFERENCE SITES AND CONDITIONS IN AGGREGATE ECOREGION XIII

The Everglades is a nutrient poor (oligotrophic) wetland, with natural populations of plants and animals adapted to extremely low nutrient conditions. Scheidt (1999) summarized and reviewed approximately 300 scientific journal articles, state, and federal reports relevant to nutrients in the Everglades. The literature summarized indicate long-term average water column phosphorus concentrations of less than 10 μg/L. Data supporting this number span three decades and were analyzed by independent laboratories (see Appendix A). For the purposes of reducing10

these data to a single value which represents an appropriate characterization of reference condition, EPA recommends a central tendency value such as the long-term geometric mean or median because of the large amount of data available, the relatively long length of time represented by the data, and the effects of hydrologic variability on water column concentration of phosphorus in this system.

Unenriched portions of the Everglades are reported to have some of the lowest rates of phosphorus accumulation in peatlands in North America. Increased surface water phosphorus from EAA canal inflows has caused elevated soil phosphorus concentrations. Studies conducted in the last decade by DeBusk et al . (1994; in press) indicate that chronic dosing has lead to increased soil P in Water Conservation Area 2A (WCA2A), the primary recipient of EAA inflows, and the front of P-enriched soils is moving south and encompassing increasingly larger areas.

Periphyton mat communities are found throughout the unimpacted Everglades marsh, especially in open water areas, sloughs and wet prairies. These mats, often referred to as calcareous mats, are known to be extremely sensitive to P enrichment. The calcareous algal mats in the hardwater calcium rich portions of the Everglades exhibit the first visible changes as a result of increased phosphorus when the dominant periphyton, calcareous blue-green algae, is replaced by soft-bodied green and blue-green algae (McCormick et al . 1999). The soft-water habitats of the Everglades also have periphyton adapted to low-nutrient conditions. These periphyton communities are comprised primarily of a type of green algae (desmids) and diatoms. Shifts in relative species abundance and an increase in pollution-tolerant species also occur as a response to nutrient enrichment in the soft-water periphyton community (McCormick et al 1999).

Reference conditions in the Everglades are defined by the native periphyton and macrophyte communities. Everglades periphyton provides multiple functions in the ecosystem. These functions include: accounts for much of the primary productivity in wet prairies and sloughs; provides habitat for aquatic animals such as invertebrates; along with macrophyte detritus, forms forming the base of the Everglades aquatic food web; is the major source of oxygenating the water for fish and other animal life in sloughs and wet prairies; maintaining low water TP concentrations; plays a role in cycling of nitrogen, phosphorus, carbon and oxygen; and contributes to the formation of marl soils.

The oligotrophic Everglades marsh system contains a mosaic of macrophyte communities, such as sloughs, wet prairies and sawgrass marshes, all of which are adapted to low nutrient conditions. This mosaic, which provides a diverse array of habitats for animals, is an important defining characteristic of the Everglades. Wet prairies encompass a group of plant communities generally described by soil type and dominant plant species. Wet prairies on peat soil are generally characterized by spikerush ( Eleocharis cellulosa ), beak rush ( Rhynchospora tracyi ), or maidencane ( Panicum hemitomon ), although dozens of plant species exist. Sloughs generally refer to deeper water areas, often dominated by white water lily ( Nymphaea odorata ), floating hearts ( Nymphoides aquatica ), and spatterdock. Bladderwort s ( Utricularia purpurea or Utricularia foliosa ) are common submerged aquatic plants that provide a substrate for dense periphyton mats. Wet prairies and sloughs in particular provide critical habitat for animals and provide cover, nesting, and feeding sites for all animal groups. The wet prairie/slough habitat is also the major feeding area in the Everglades for both wintering and nesting wading birds, especially during the dry season when fish concentrations provide food for their nestlings (Scheidt 1999).

An important characteristic of unimpacted wet prairies and sloughs is their diversity and the large number of native plant species (Scheidt 1999). Multiple factors are responsible for the alteration and maintenance of plant community structure in the Everglades, including nutrients, fire, disturbance, and hydroperiod. Elevated water phosphorus concentrations or elevated soil phosphorus concentrations in the Everglades are associated with elimination of submerged vegetation species including the Utricularia- periphyton complex and expansion of nutrient-11

tolerant macrophytes such as cattail or Sagittaria lancifolia (Arrowhead) into areas previously dominated by sawgrass, sloughs or wet prairies. Historically, cattail was a minor component of the Everglades landscape.

The table below (Table 1) shows the reference condition recommendations for the Aggregate nutrient ecoregion for water column TP and vegetation. The recommendations are based on literature values.

Table 1: Reference Conditions for Aggregate Ecoregion XIII.

Aggregate Ecoregion XIIISouthern Florida Coastal Plain Reference Conditions

Total Water Column Phosphorus (μg/L) 10

Periphyton No significant change in relative species abundance

These recommendations were derived based on data from the over 300 peer-reviewed publications from

Everglades research. They may not be appropriate for all the wetlands within the Everglades because the mosaic character of the system may result in site-specific conditions that do not reflect the characteristics were used to derive these reference values. EPA encourages the State and Tribes of Florida to apply this approach in other wetlands within the ecoregion.

EPA also recommends that States and Tribes develop reference conditions and criteria for soil phosphorus levels since it is considered a necessary indicator of eutrophication and phosphorus condition within the Everglades. Studies have indicated that 300-600 mg P/kg soil is the preferred range for organic soils. However, these same levels may not be appropriate for mineral soils in other parts of the Everglades.

6.0 MODELS USED

No models were directly used in the preparation of this document. However, many models have been produced to model nutrient effects in the Everglades. An overview of the models used in the Everglades is provided in the Everglades Interim Report (1999). Summaries and detailed descriptions of models developed for the Everglades can be found in McCormick et al . (1999) and Phosphorus Biogeochemistry in Subtropical Ecosystems (1999), respectively.

It is recognized that, distinct from ambient monitoring or empirical efforts, field and laboratory experiments can elucidate specific processes and establish cause and effect. These studies (such as field nutrient dosing studies, mesocosm studies, or laboratory mesocosm or microcosm experiments) can facilitate causal interpretation of data. (Lean, et al ., 1992; Hopkinson, et la. , 1998).

7.0 FRAMEWORK FOR REFINING RECOMMENDED NUTRIENT CRITERIA FOR AGGREGATE ECOREGION XIII

Information on each of the following six weight of evidence factors is important to refine the criteria presented in this document. All elements should be addressed in developing criteria. It is our expectation that EPA Regions and States (as RTAGs) will consider these information elements as States/Tribes develop their criteria. This section should be viewed as a work sheet to assist in the completion of the nutrient criteria assessment. For example, States and Tribes should address factors that have the potential to impact downstream receiving waters, particularly12

Florida Bay and the Keys. If these elements are ultimately unaddressed, EPA may rely on the proposed reference conditions and criteria recommendations presented in this document, and other literature and information readily available to the HQ nutrient team to develop nutrient water quality recommendations for this ecoregion.

7.1 Example Worksheet for Developing Aggregate Ecoregion and Subecoregion Nutrient Criteria

C Literature sources

C Historical data and trends

C Reference condition

C Models

C RTAG expert review and consensus

C Downstream effects13

7.2 Setting Seasonal Criteria

States/Tribes may choose to develop criteria which reflect each particular season or a given year when there is significant variability between seasons/years or designated uses that are specifically tied to one or more seasons of the year (e.g., recreation, fishing). Obviously, this option is season-specific and would also require increased monitoring within each season to assess compliance.

7.3 Site-specific Criteria Development

Criteria may be refined in a number of ways. The best way to refine criteria is to follow the critical elements of criteria development as well as to refer to the Wetlands technical guidance manual (due out for publication in 2001).

The Technical Guidance Manual presents sections on each of the following factors to consider in setting criteria

Ç refinements to ecoregions Ç classification of waterbodies Ç setting seasonal criteria to reflect major seasonal climate differences Ç accounting for significant or cyclical rainfall events - high flow/low flow conditions Ç Wetland types

8.0 LITERATURE CITED

Bechtel, Timothy, Steven Hill, Nenad Iricanin, Kimberly Jacobs, Cheol Mo, Victor Mullen, Richard Pfeuffer, David Rudnick and Stuart Van Horn. 1999. Status of Compliance with Water Quality Criteria in the Everglades Protection Area and tributary waters. Chapter 4 in Everglades Interim Report . South Florida Water Management District. West Palm Beach, Florida.

Davis, Steven M. 1989. Sawgrass and Cattail Production in Relation to Nutrient Supply in the Everglades. pp. 325-341 in "Freshwater Wetlands and Wildlife", CONF-860301, DOE Symposium Series No. 61, R. R. Scharitz and J. W. Gibbons (eds.), USDOE Office of Scientific and Technical Information, Oak Ridge, Tennessee.

DeBusk, W. F., K. R. Reddy, M. S. Koch, and Y. Wang. 1994. Spatial distribution of soil nutrients in a northern Everglades marsh: Water Conservation Area 2A. Soil Sci. Soc. Am. J. 58:543-552

.
DeBusk, W. F., S. Newman, and K. R. Reddy. (in press). Spatio-temporal patterns of soil phosphorus enrichment in Everglades WCA-2A. Journal of Environmental Quality.

Everglades Interim Report . 1999. South Florida Water Management District.

Hopkinson, Charles Jr., Patrick Mulholland, Lawrence Pomeroy, Robert Twilley and Dennis Whigham. 1998. External panel report to the Florida Department of Environmental Protection. Overview and evaluation of Everglades nutrient threshold research for the period October 1996 to October 1997. 47 p.

Lean, David, Kenneth Reckhow, William Walker and Robert Wetzel. 1992. Everglades nutrient threshold research plan. July 3, 1992. 12 p.14

McCormick, Paul, Susan Newman, Shili Miao, Ramesh Reddy, Dale Gawlick, Carl Fitz, Tom Fontaine and Darlene Marley. 1999. Ecological needs of the Everglades. Chapter 3 in Everglades Interim Report . South Florida Water Management District. West Palm Beach, Florida.

Omernik, J. A. 1995. Ecoregions: A Spatial Framework for Environmental Management . In: Biological Assessment and Criteria: Tools for Water Resource Planning and Decision Making, Wayne S. Davis and Thomas P. Simon (editors), pp. 49-66. Lewis Publishers an imprint of CRC Press, Boca Raton, FL.

Omernik, J. A. 1998. Draft Aggregations of Level III Ecoregions for the National Nutrient Strategy

. [http://www.epa.gov/ost/standards/ecomap.html].

Reddy, K. R., G. A. O’Connor, and C. L. Schelske, 1999. Phosphorus Biogeochemistry in Subtropical Ecosystems . eds. Lewis Publishers, Boca Raton, FL.

Reddy, K. R., Y. Wang, W. F. DeBusk, M. M. Fisher and S. Newman. 1998. Forms of Soil Phosphorus in selected hydrologic units of the Florida Everglades. Soil Sci. Soc. Am J. 62:1134-1147.

Scheidt, D. J., M.D. Flora, and D. R. Walker. 1989. Water Quality Management for Everglades National Park. P. 377-390. In: “Wetlands: Concerns and Success”. American Water Resources Association, Bethesda, MD. USA.

Scheidt, D. J. 1999. EPA Memorandum. Numeric phosphorus water quality criterion for the Everglades as adopted by the Miccosukee Tribe of Indians of Florida for Class III-A Waters. May 20, 1999.

Swift, D. R.1984. Periphyton and water quality relationships in the Everglades Water Conservation Areas. Pp. 97-117 in "Environments of South Florida: Present and Past II" Miami Geological Society, Coral Gables, Florida. 551 pp.

U.S. EPA. April 2000, Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, EPA-822-B00-001.

9.0 APPENDICES

Appendix A: Scheidt, D. J. 1999. EPA Memorandum. Numeric phosphorus water quality

criterion for the Everglades as adopted by the Miccosukee Tribe of Indians of Florida for Class III-A Waters. May 20, 1999.

Appendix B: EVERGLADES NUTRIENT-RELEVANT REFERENCES. Compiled by D.

Scheidt, USEPA, May 1999

.APPENDIX AMemorandum

To: Robert F. McGhee

Director, Water Management Division

Through: Richard Harvey

Director, South Florida Office

From: Dan Scheidt

Senior Scientist

South Florida Initiative

Subject: Numeric phosphorus water quality criterion for the Everglades as adopted by the

Miccosukee Tribe of Indians of Florida for Class III-A Waters

Date: May 20, 1999

The Miccosukee Tribe of Indians of Florida (the Tribe) has submitted to the United States Environmental Protection Agency (USEPA) a numeric criterion for total phosphorus of 10 partsper billion (ppb, or micrograms per liter). The Tribe adopted this numeric criterion for Class IIIA waters of the Miccosukee Tribe’s Federal Reservation in the Everglades on December 19,

1997. The Tribe has defined Class III-A waters within the Federal Reservation as: "Those Tribal water bodies which are used for fishing, frogging, recreation (including airboating), and the propagation and maintenance of a healthy, well-balanced population of fish and other aquatic life and wildlife. These waters have been primarily designated for preservation of native plants and animals of the natural Everglades ecosystem." (page 23 of the Final Miccosukee Environmental Protection Code, Subtitle B, dated December 19,1997). The Tribal water quality standard for

nutrients includes the narrative statement: “In no case shall nutrient concentrations of Tribal Class I or Class III-A surface waters be altered so as to cause an imbalance in natural populations of aquatic flora or fauna.” (page 11). The areas which the Tribe has designated as Class III-A waters include the north grass, south grass and gap areas (Everglades habitat within western Water Conservation Area 3A) (Figures 1 and 2).

PROBLEM STATEMENT

The determination that USEPA must make in approving or disapproving the Miccosukee 10 ppb phosphorus criterion is whether it is protective of the Class III-A designated use.

The Everglades marsh is extremely oligotrophic (nutrient poor). The mosaic of native plant communities and associated animals developed under, and are adapted to, very lowphosphorus conditions. Phosphorus enrichment in the Everglades has caused a series of welldocumented impacts (see below) such as loss of water column dissolved oxygen, loss of native plant life (periphyton (micro-algae) and macrophytes), and loss of preferred foraging habitat for wading birds.2

As summarized by the external peer-review panel to the Florida Department of Environmental Protection (Hopkinson et al. 1998), in phosphorus-limited aquatic systems such as the Everglades, concentrations of total phosphorus in the water column are very low, and a small pool of dissolved phosphorus cycles or turns over very rapidly.

Added phosphorus is assimilated rapidly into biomass or adsorbed by particulate matter. Phosphorus concentrations in the water will begin to increase only when a number of other living and non-living pools begin to saturate with excess P. For this reason, measurements of the standing stocks of total P in Everglades water are a relatively insensitive measure of significant changes of the system. By the time the concentration of total P in water has increased significantly, the system has already begun to approach P saturation in other components of the system (periphyton, macrophytes, sediments) and species succession may well be underway. In terms of time, the microbial components will be the first to change, followed much later by changes in macro-organisms, such as sawgrass to cattails. The stages in this succession can be seen in the present-day Everglades.

(Hopkinson et al.1998, page 11).

Phosphorus condition in the “Natural Everglades Ecosystem” is depicted in Figure 3. In contrast, Figure 4 depicts the phosphorus-impacted Everglades system. Figure 5, “Cultural Eutrophication”, depicts the succession of changes caused by phosphorus enrichment in the Everglades, proceeding from those that are not visible to the naked eye (such as decreased alkaline phosphatase activity or increased soil phosphorus content) to those that are visible (such as changes in periphyton communities and macrophyte species composition).

Ultimately, determining whether a numeric TP criterion will protect Class III-A Everglades plant and animal communities appears to revolve around three issues: 1) selecting appropriate indicators of some change in the marsh ecosystem (sensitive indicators such as alkaline phosphatase activity or periphyton species versus less sensitive indicators such as macrophyte species); 2) determining what constitutes an imbalance in natural populations of aquatic flora or fauna: 3) determining what spatial extent of phosphorus impact, if any, is acceptable. These issues are not solely scientific ones.

The numeric phosphorus water quality criterion adopted by the Tribe must be sufficiently stringent to protect the Class III-A designated use, including preservation of native plants (periphyton and macrophytes) and animals of the natural oligotrophic Everglades ecosystem for decades or centuries. “This issue, obviously, is what amount of input of phosphorus to the Everglades will result in system change after several decades or a century...” (Hopkinson et al.1998, page 14). Phosphorus impacts in the Everglades are well-documented. This documentation includes observational studies as well as controlled experimental manipulations. Some of the observed phosphorus impacts have been based on short-term phosphorus addition or dosing experiments, with the nutrient addition taking place for a duration of a few weeks up to a few (less than five) years. With this type of study although it is possible to observe the phosphorus impacts that occur within the short-term duration of dosing, it is not possible to observe or infer what other indirect effects may occur later as the added phosphorus continues to3

cycle. Nor is it possible to infer what effects may have occurred later had dosing at the same concentration continued for a much longer period of time, such as decades or even centuries. It is not possible to identify all final long-term direct and indirect ecological impacts from short-term nutrient addition studies. Thus, there is a risk that a numeric criterion based solely on short-term (less than 5 years) dosing without also considering long-term observational studies would not be protective of the Class III-A designated use.

SUMMARY

Extent of the Review

A very extensive body of peer-reviewed scientific literature and data has been assembled during the last three decades concerning Everglades water quality, periphyton communities, macrophyte communities, and the impacts of phosphorus enrichment on Everglades plants and animals. USEPA received 110 documents from the Tribe in support of their adoption of the numeric phosphorus criterion. These documents have been reviewed by USEPA. In addition, an effort was made to identify and review other equally relevant scientific literature specific to the Everglades. A listing (attached) of the published reports identified numbers about 300 scientific documents. All of this literature is specific to the Everglades and is relevant to eutrophication. No other wetland system and few, if any, other bodies of water in the world have been the subject of so much scientific information concerning phosphorus conditions and the ecological impacts of phosphorus enrichment.

A brief review is presented of the scientific documentation about Everglades natural background phosphorus conditions and the impacts of phosphorus enrichment. This review relied on published scientific literature (peer-reviewed publications in scientific journals as well as technical publications by agencies such as the South Florida Water Management District, United States Geological Survey or USEPA). The reviewed literature included publications about Everglades:

C phosphorus conditions including the Everglades Agricultural Area,

C periphyton communities,

C macrophyte communities,

C cycling of oxygen, carbon, sulfur, and nitrogen, and

C wading bird foraging habitat.

The literature review excluded hundreds of additional scientific publications that primarily concern Everglades:

C hydrology,

C Phase II phosphorus treatment technology,

C water management,

C mercury contamination,

• pesticides,

• botany, and

C soils.4

An extensive additional body of scientific information and opinion exists that was not included: published abstracts, memoranda, depositions, various legal documents, court exhibits, and public meetings and conferences.

Summary of conclusions

Based on the best available scientific information and the review that follows, the Tribe’s 10 ppb criterion for phosphorus meets the requirements of 40 CFR §131.11 as it is protective of the Class III-A designated use, and review of published available information and data shows that the value is scientifically defensible.

This review has identified the following major points, which are expanded upon in the text that

follows:

C The Everglades marsh system is naturally extremely oligotrophic. Un-impacted interior portions of the Everglades marsh have long-term average water column phosphorus concentrations of approximately 10 ppb or even less.

C The native plant and animal communities in the Everglades marsh developed under and are adapted to these very low phosphorus conditions.

C Phosphorus is the primary limiting nutrient in the oligotrophic Everglades marsh
system.

C Microbial processes are important in controlling nutrient cycling in wetlands and they play an important role in determining water quality and maintaining an ecosystem’s normal productivity. Elevated water column or soil phosphorus concentrations in the Everglades have been implicated as cause for disruption of various microbial processes.

C Periphyton communities are an important defining characteristic of the Everglades marsh ecosystem. According to the scientific literature, Everglades periphyton accounts for much of marsh primary productivity in wet prairies and sloughs; provides habitat for aquatic animals such as invertebrates; along with macrophyte detritus, forms the base of the Everglades aquatic food web; is the major source of oxygen for fish and other animal life in sloughs and wet prairies; maintains low water TP concentrations; plays a role in cycling of nitrogen, phosphorus, carbon and oxygen; and affects formation of marl soils. Periphyton communities are extremely sensitive to phosphorus enrichment. Phosphorus enrichment at levels above 10 ppb TP has been shown to cause a loss of Everglades native periphyton communities.5

C Surface water dissolved oxygen in pristine Everglades wet prairie and slough communities often exhibits a strong diel cycle, with concentration at a particular location ranging from 0 mg/l in early morning to over 12 mg/l in late afternoon. Everglades fish are adapted to these conditions. In contrast, oxygen levels in

nutrient-rich locations within WCA2A have been shown to often be undetectable and rarely exceed 2 mg/l, with protracted periods of oxygen depletion.

C Unenriched portions of the Everglades are reported to have some of the lowest rates of phosphorus accumulation in peatlands in North America. Increased surface water phosphorus has caused elevated soil phosphorus concentrations. Over 51% of WCA2A has been reported as having increased soil phosphorus.

C The oligotrophic Everglades marsh system contains a mosaic of macrophyte communities, such as sloughs, wet prairies and sawgrass marshes, all of which are adapted to low nutrient conditions. This mosaic is an important defining characteristic of the Everglades. Wet prairies and sloughs in particular provide critical habitat for animals and provide cover, nesting, and feeding sites for all animal groups. Elevated water phosphorus concentrations or elevated soil phosphorus concentrations in the Everglades are associated with elimination of submerged vegetation species including the important Utricularia- periphyton complex and expansion of nutrient-tolerant macrophytes such as cattail or Sagittaria into areas previously dominated by sawgrass, sloughs or wet prairies.

C Shallow, open water areas with scattered to moderately dense emergent macrophytes are the preferred foraging habitat for Everglades wading birds. Conversion of these areas to dense emergent macrophytes due to phosphorus enrichment constitutes a loss of wading bird foraging habitat.

C Phosphorus enrichment initiates a succession of changes within the marsh system. Initial changes, such as those that occur at the microbial level, are not visible. Visible impacts eventually occur, such as loss of native flora or fauna.

C The oligotrophic Everglades marsh system has very low assimilative capacity, or tolerance, for phosphorus before changes in ecosystem structure and function occur.

C The well-documented phosphorus impacts in WCA2A have taken place since the discharge of phosphorus-rich water through the S-10 structures beginning about

1960 (a period of about four decades). There is no information available concerning low-level additions of excess phosphorus for a century or more.

• The nutrient dosing studies and observational studies described below indicate that total phosphorus concentrations above 10 ppb have been shown to cause impacts to native Everglades periphyton and macrophytes such as Utricularia purpurea that are adapted to low phosphorus conditions. The best available scientific information indicates that average TP concentrations greater than 10 ppb, in general, can be6 expected to be inadequate for long-term protection of the Class III-A designated use. Therefore the Tribe’s adopted numeric phosphorus criterion of 10 ppb is not overly protective.

• Currently available scientific information reviewed also indicates that the Tribe’s proposed numeric criterion of 10 ppb is protective of the Class III-A use and the native Everglades periphyton and macrophytes. Although some data have identified long-term phosphorus concentrations within the Everglades as low as 5.0 ppb, EPA’s review identified no currently available published scientific information documenting changes in the natural flora or fauna resulting from total phosphorus concentrations in the 5 ppb to 10 ppb range. If new data or information are presented in the future that demonstrate that 10 ppb is not protective of the Class III-A use, the Tribe should revise the criterion accordingly.

Therefore, USEPA has determined that the 10 ppb total phosphorus criterion is protective of the Class III-A designated use, is reasonable, and is scientifically defensible.

REVIEW OF RELEVANT SCIENTIFIC INFORMATION

Phosphorus is a nutrient that is essential to the growth of organisms and is often the nutrient that limits primary productivity in a water body. Phosphorus can exist in a water body as organic and inorganic forms. Phosphorus cycles in aquatic environments from the organic and inorganic state, and vice versa, with microorganisms playing a key role (Jones, 1996). Phosphorus data from water bodies is typically reported as total phosphorus and inorganic soluble phosphate (orthophosphate). The citations that follow include mention of these two forms. Phosphate is the form that is considered to be readily available for biological uptake.

In the summary that follows, the term “Everglades” is used to refer to the freshwater marsh habitats, such as sawgrass marsh, wet prairies and sloughs, in the greater Everglades system. The geographic area includes Loxahatchee National Wildlife Refuge (the Refuge), Everglades National Park (the Park), the Holeyland, the Rotenberger Tract, and all of the Water Conservation Areas (2A, 2B, 3A and 3B). The water quality and ecology of the Tribe’s Class III-A waters are generally consistent with the water quality and ecology found in the greater Everglades system.

1- Reference conditions in the Everglades marsh ecosystem.

The Everglades is a nutrient poor (oligotrophic) wetland, with natural populations of plantsand animals adapted to extremely low nutrient conditions. A reasonable approximation of longterm average surface water total phosphorus concentration is 10 ppb. The smallest but most widely distributed plant community in the Everglades is an assemblage of micro-algae referred to collectively as periphyton. Everglades periphyton generally is comprised of three major divisions or groups: diatoms, blue-green algae and green algae (Browder et al., 1994). Periphyton exhibits three growth forms in the Everglades: benthic (growing on the soil surface), epiphytic (growing attached to rooted vegetation) and floating (growing on the water surface sometimes in association with other floating vegetation such as Utricularia purpurea ) (McCormick et al. 1999). These7

periphyton mat communities are found throughout the unimpacted Everglades marsh, especially in open water areas, sloughs and wet prairies. These mats, often referred to as calcareous mats, are known to be extremely sensitive to phosphorus enrichment. The widespread distribution of floating periphyton mats throughout the Everglades as observed during 1995-1996 is presented by Stober et al. (1998).

Periphyton provides multiple functions in the marsh ecosystem. These have been summarized by Browder et al. (1994), McCormick et al. (1998) and McCormick et al. (1999). Everglades periphyton: accounts for much of marsh primary productivity in wet prairies and sloughs; provides habitat for aquatic animals such as invertebrates; along with macrophyte detritus, forms the base of the Everglades aquatic food web; is the major source of oxygen for fish and other animal life in sloughs and wet prairies; maintains low water TP concentrations; plays a role in cycling of nitrogen, phosphorus, carbon and oxygen; and affects formation of marl soils.

Everglades plant communities, along with the factors contributing to plant community distribution and change, have been studied extensively. Recent vegetation classification maps have been published for Loxahatchee National Wildlife Refuge, WCA2A, and the Shark River Slough portion of Everglades National Park. The oligotrophic Everglades marsh system contains a mosaic of macrophyte communities, such as sloughs, wet prairies and sawgrass marshes, all of which are adapted to low nutrient conditions. This mosaic, which provides a diverse array of habitats for animals, is an important defining characteristic of the Everglades. Wet prairies encompass a group of plant communities generally described by soil type and dominant plant species. Wet prairies on peat soil are generally characterized by spikerush ( Eleocharis cellulosa ), beak rush ( Rhynchospora tracyi ), or maidencane ( Panicum hemitomon ), although dozens of plant species exist. Sloughs generally refer to deeper water areas, often dominated by white water lilly ( Nymphaea odorata ), floating hearts ( Nymphoides aquatica ), and spatterdock. Bladderwort ( Utricularia purpurea or Utricularia foliosa ) are common submerged aquatic plants that provide a substrate for dense periphyton mats. Wet prairies and sloughs in particular provide critical habitat for animals and provide cover, nesting, and feeding sites for all animal groups. The wet prairie/slough habitat is also the major feeding area in the Everglades for both wintering and nesting wading birds, especially during the dry season when fish concentrations provide food for their nestlings (Gunderson and Loftus, 1993). An important characteristic of unimpacted wet prairies and sloughs is their diversity and the large number of native plant species (Olmstead et al, 1980; Olmstead and Loope, 1984; Goodrick, 1974; Gunderson and Loftus, 1993). Multiple factors are responsible for the alteration and maintenance of plant community structure in the Everglades, including nutrients, fire, disturbance, and hydroperiod. Elevated water phosphorus concentrations or elevated soil phosphorus concentrations in the Everglades are associated with elimination of submerged vegetation species including the Utricularia- periphyton complex and expansion of nutrient-tolerant macrophytes such as cattail or Sagittaria lancifolia (Arrowhead) into areas previously dominated by sawgrass, sloughs or wet prairies. Historically, cattail was a minor component of the Everglades landscape.

The following discussion of Everglades animals is taken largely from McCormick et al. (1999). Aquatic invertebrates such as insects, snails and crayfish play an important role in the Everglades food web. Most invertebrates feed directly on periphyton and/or plant detritus and are then consumed by other animals. Invertebrates tend to be concentrated in periphyton-rich habitats8

such as sloughs or wet prairies where dissolved oxygen is plentiful and food is more readily available. Fish are a key link between invertebrates and predators, such the wading birds for which the Everglades is widely renown. Fish biomass in the natural (oligotrophic) Everglades is low relative to other wetlands. Turner et al. (in press) report that the natural condition in the oligotrophic Everglades is one of a high periphyton standing stock, but low invertebrate and fish standing stock.

The conditions described above are representative of unimpaired Miccosukee Tribal Waters. SFWMD has produced a classified vegetation map of northern WCA3A dated 1 July 1997. This map was based on September 1994 and June 1995 color infrared aerial photographs, and involved extensive ground-truthing (see Doren et al., 1999 for methods). The vegetation communities within the Tribal Waters indicative of unimpaired conditions include a mosaic of sawgrass marsh and wet prairies dominated by maidencane or spikerush. In addition, USEPA made visual observations of the Tribal Waters by airboat on July 30, 1998 and by helicopter on November 13,

1998.

2- The Everglades marsh system is extremely oligotrophic. Un-impacted interior portions of the Everglades marsh have long-term average water column phosphorus concentrations of approximately 10 ppb or less.

Relevant scientific literature: Gleason et al., 1974b; Gleason et al., 1975a; Millar, 1981; Swift and Nicholas, 1987; Flora et al., 1988; Scheidt et al., 1989; Davis, 1991; Walker, 1991; SFWMD, 1992; Reddy et al., 1993; Richardson et al., 1994; Walker, 1995; McCormick et al., 1996; Walker, 1997a; Richardson et al., 1997; Vaithiyanathan et al., 1997; Stober et al., 1998; McCormick et al., 1999.

Long-term average concentrations of 10 ppb or less have been documented repeatedly throughout the Everglades system, including Loxahatchee National Wildlife Refuge, Water Conservation Area 2 (WCA2), Water Conservation Area 3 (WCA3), and Everglades National Park. These complementary and corroborative data come from several independent studies conducted by different investigators spanning a time-frame of three decades. These data come from several independent analytical laboratories, including South Florida Water Management District (SFWMD), Florida Department of Environmental Protection (FDEP), Duke University, the National Park Service, and the Florida International University Southeast Environmental Research Program (FIU SERP).

Surface water phosphorus concentrations within the Everglades fluctuate naturally with water conditions. Marsh phosphorus concentrations have been shown to vary with water depth, with higher concentration excursions occurring during periods of low water or marsh drying (Walker, 1997a; McCormick et al., 1999). McCormick et al. (1999) reported that occasional high P concentrations at Everglades reference stations can be attributed to difficulty in collecting water samples that are not contaminated by flocculent sediment when water depths are low (a few inches), P released as a result of oxidation of exposed soils, or mobilization of P with fires. This represents recycling within the marsh internal phosphorus pool, as opposed to marsh exposure to additional phosphorus from external sources. In spite of this internal cycling, 10 ppb is a reasonable approximation of long-term average or median phosphorus concentrations at Everglades reference

stations.9

Some water samples from the Everglades marsh that are analyzed for phosphorus are below the limits of analytical detection. For example, the phosphorus analytical limit is 4 ppb for the SFWMD laboratory and varies across laboratories. In these cases, the low end of the distribution of phosphorus concentration at a sampling location is artificially truncated, and the actual median or average phosphorus concentration at a location would in reality be even lower than the reported median or average.

In a study of nutrient uptake and rates of nutrient deposition in WCA2A from 1973-1974, Gleason et al. (1974b) documented phosphorus gradients downstream of the S-10 structures, with background orthophosphate concentrations of 2 ppb.

During 1974 Gleason et al. (1975a) studied the effect of agricultural runoff on algal communities at 5 wet prairie marsh stations within the Loxahatchee National Wildlife Refuge. The orthophosphate phosphorus concentration reported for all of the 57 water samples collected was less than 2 ppb.

Swift and Nicholas (1987) summarized 1977-1983 water quality throughout LNWR, WCA2A and WCA3A interior marsh sites. They reported mean total phosphate concentrations of 14 ppb for LNWR, 11 ppb for WCA2A and 9 ppb for WCA3A, with a grand mean of 11 ppb.

Swift (1981) summarized average total dissolved phosphate concentration at these same interior marsh sites from 1978-1979. The average total dissolved phosphate concentration at interior marsh sites within LNWR, WCA2A and WCA3A was 2 to 5 ppb.

Walker (1995, figure 1) presented surface water mean TP concentration at water control structures and marsh locations throughout the Everglades system. Mean TP concentration at remote marsh stations away from alligator ponds within Everglades National Park ranged from 5.2 ppb at P-37 to 10.8 ppb at P-35 (statistical summary used for preparation of Figure 1 received from the author). The grand mean of the eight station means was 8.3 ppb.

Grimshaw et al. (1997) reported 8 ppb as the 1994-1995 mean surface water TP concentration at an unenriched slough site within WCA2A.

In a 1991-1996 study of WCA2A sloughs, Vaithiyanathan et al. (1997) found an average water column dissolved phosphate concentration of 5 ppb (n=2557) and total phosphorus (TP) concentration of 9 ppb (n=1659), with individual TP concentration measurements ranging from 2 to 20 ppb.

In a summary of a 1992-1996 nutrient dosing study in WCA2A, Richardson et al. (1997, pages 15-32 and 15-44) reported mean 1993-1996 surface water TP concentrations at 16 locations in the control area ranging from 8.8 ppb to 12.1 ppb, with a grand median of 9.1 ppb and a grand mean of 10.9 ppb.

Walker (website:“http://www2.shore.net/~wwwalker/clearwtr/maps/sld010.htm, 04/04/98) depicted TP in marsh surface water sites and water control structures throughout the Everglades10

from 1992-1996. Geometric mean TP concentration for 1992-1996 was 10 ppb or less at all 14 marsh stations within LNWR, all 9 marsh stations within ENP, and all 12 marsh stations within WCA2A or WCA3A that are away from sources of phosphorus enrichment.

McCormick et al. (1999) summarized surface water TP at interior marsh locations throughout LNWR, WCA2A, WCA3A, and ENP. The median for each of the eight stations ranged from about 4 to 10 ppb. The lowest median of about 5 ppb (n=100) was for WCA3A station CA3-

15.

In 1991 the best available surface water TP data (data source: SFWMD) were used to

determine the surface water TP condition that existed from 1979-1988 at water structures discharging into Everglades National Park and at interior marsh stations within Loxahatchee National Wildlife Refuge. These data became the basis for phosphorus limits or levels intended to maintain the water quality condition that existed from 1979-1988 in order to protect the oligotrophic marsh system including the associated plants and animals within the Refuge and the Park. The development of and scientific basis for these water column phosphorus limits or levels is described in SFWMD (1992) and Walker (1997), and is summarized in the next two paragraphs.

Phosphorus limits for inflows to Everglades National Park were derived in 1991. Attaining these concentrations would continue to provide the Park with the quality of water that existed from 1979-1988. These apply to the annual flow-weighted mean TP concentration of inflows composited across the five water delivery structures to Shark River Slough (the S-12 structures and S-333). Although the required phosphorus limits vary from a flow-weighted mean of about 13 ppb during dry years to about 8 ppb during wet years, if attained these limits would provide Shark River Slough a long-term average flow-weighted mean inflow TP concentration of approximately 8 ppb. Phosphorus limits were also established for water delivered to the Taylor Slough and Coastal Basin portion of the Park. Attaining these limits is expected to provide these portions of the Park with a long-term average flow-weighted mean inflow TP concentration of 6 ppb.

In addition, separate marsh water column phosphorus levels were derived in 1991 for Loxahatchee National Wildlife Refuge based on historic data from SFWMD at 14 interior marsh stations. To account for the observed correlation between marsh total phosphorus concentration and water depth (as determined by stage) the phosphorus concentration levels (determined monthly) vary with the average interior water level on the date of sample collection. Although the required phosphorus levels vary from 17 ppb at low water depth to 7 ppb at high water depth, attaining these concentrations would be expected to provide the Refuge with a long-term geometric mean concentration of approximately 7 ppb TP at the 14 interior marsh stations.

3- Phosphorus is the primary limiting nutrient in the oligotrophic Everglades marsh
system

.

Relevant scientific literature: Stewart and Ornes, 1975; Stewart and Ornes, 1983; Swift, 1984; Swift and Nicholas, 1987; Flora et al., 1988; Hall and Rice, 1990; Davis, 1991; Koch and Reddy, 1992; Grimshaw et al., 1993; Vymazal et al., 1994; Craft et al., 1995; Craft and Richardson, 1997; Vymazal and Richardson, 1995; McCormick and O’Dell, 1996; Vaithiyanathan et al., 1997a; Daoust and Childers, 1999.11

Investigators have used two approaches to conclude that phosphorus is the limiting nutrient in unenriched portions of the marsh system. The first approach is identifying nutrient ratios within water, periphyton tissue and macrophyte tissue (Swift, 1984; Swift and Nicholas, 1987; Davis, 1991; Koch and Reddy, 1992; Grimshaw et al., 1993; Daoust and Childers, 1999). For example, in a 1991-1996 study of WCA2A sloughs, Vaithiyanathan et al. (1997a) concluded that nutrient ratios in surface water and in the periphyton and macrophyte tissues suggest strong P-limitation in the Everglades sloughs. (Page 5-21).

Daoust and Childers (1999) studied the relationships between tissue nutrient content, species productivity, and species abundance for seven plant species in sawgrass marsh or wet prairies. They found that the dominant plants in both communities ( Cladium jamaicense in the sawgrass community, and Eleocharis spp. and Sagittaria lancifolia in the wet prairie) are strongly limited by phosphorus availability. They concluded that although no single environmental factor is responsible for controlling all species that occur, a majority of the plant species within this system are limited by phosphorus availability.

The second approach is nutrient dosing experiments (Stewart and Ornes, 1975; Stewart and Ornes, 1983; Flora et al., 1988; Hall and Rice, 1990; McCormick and O’Dell, 1996). In a 1983- 1984 nutrient dosing study in an Everglades National Park wet prairie dominated by Eleocharis spp. and Utricularia spp. (Flora et al., 1988; Hall and Rice, 1990), one flow-through channel was dosed with phosphate only for one year at an average concentration of 27 ppb while a second channel was dosed with nitrate only at an average of 85 ppb. The background concentrations in the adjacent reference sites averaged 6 ppb phosphate and 11 ppb nitrate. In the phosphate only channel, plant tissue phosphorus was increased, Utricularia was eliminated, Panicum and Sagittaria became the dominant macrophytes, plant biomass was increased, periphyton phosphorus content changed and the native periphyton community was lost. These changes were not observed in the channel dosed with nitrate only or the reference sites. All treatments and the reference site were exposed to the same hydroperiod and water depth.

4- Impacts of phosphorus enrichment: microbial processes.

Relevant scientific literature: Maltby, 1985; Amador et al., 1992; Lean et al., 1992; Amador and Jones, 1993; Koch-Rose et al., 1994; Stober et al., 1996; Stober et al., 1998; McCormick et al., 1999; Newman et al., in press.

McCormick et al. (1999 page 3-13) summarized the importance of microbes in wetland systems as follows: “Wetlands host complex microbial communities including bacteria, fungi, protozoa and viruses. The size and diversity of microbial communities are related directly to the quality and quantity of the resources (i.e., nutrients, energy sources) available in the system. Microbial biomass and activity is highest in habitats where these resources are concentrated, including periphyton mats, plant litter, and surface soils. Microbial processes regulate major nutrient cycles in wetlands and, therefore, play an important role in determining water quality and ecosystem productivity.” Microbial populations regulate the decomposition of organic matter and the cycling of nutrients, including carbon, nitrogen, and phosphorus. Increasing water column phosphorus or soil phosphorus has been implicated as cause for the disruption of various microbial12

processes within the Everglades system. Lean et al. (1992) in an Everglades nutrient threshold research plan, stated that “Sufficient data from the Everglades and other wetland ecosystems exist to indicate that microorganisms (algae, bacteria) and their metabolic influences on organic detrital and soil components are critical to the retention, cycling, and biological impacts of phosphorus. Organisms with the fastest turnover rates respond most rapidly to P enrichments. Their growth rates and composition provide initial indicators of imbalance.” (page 7).

In a nutrient dosing study performed in a wet prairie within Everglades National Park during 1983 and 1984, Maltby (1985) deployed cellulose strips to observe the effects of nutrient loadings on decomposition profiles in the water column and peat. He observed that cellulose decomposition within the water column was accelerated by nitrate and phosphate dosed together and by phosphate alone but not by nitrate alone, and that the decomposition profile increased sharply in the peat within areas where P had been added. He stated that nutrient addition “may elicit marked acceleration of decomposition not only of litter but also of organic matter stored in the sedimentary peat system. It is impossible to be certain that this will not result in further release of nutrients previously fixed by the peat and a progressive instability developed in the ecosystem” (page 457).

In studies of phosphate and phosphorus removal by peat soils from Everglades National Park, Amador et al. (1992), Jones and Amador (1992), and Amador and Jones (1992) found that microbial processes play a role in determining how much phosphorus Everglades peat can store, continued exposure to water containing high P concentrations significantly decreased the available P storage capacity of Everglades soils, these soils have a finite ability to remove and store phosphorus, and P pollution may have a marked, long-term effect on microbial respiration in organic soils with low P content.

Phosphatase enzymes, such as alkaline phosphatase, have been used as a sensitive indicator of phosphorus enrichment in aquatic systems (Jones, 1996; Newman et al., in press). Stober et al. (1998) used alkaline phosphatase activity in surface water as a sensitive indicator of phosphorus condition. During 1995 and 1996 marked gradients were observed throughout the Everglades marsh, with the interior of LNWR and ENP having the highest alkaline phosphatase activity (indicative of a condition void of readily available phosphorus). The area that consistently had the lowest alkaline phosphatase activity (indicating that phosphorus within the water column was in a readily available form) was the northern portion of WCA3A and WCA2A adjacent to canals delivering water of high phosphorus content.

McCormick et al. (1999) summarized the impact of increased P loading to the Everglades on microbial and biogeochemical processes. P loading has been shown to affect the quality and quantity of organic matter, rates of nutrient accumulation, microbial biomass and community composition, and biogeochemical cycling. Moreover, P enrichment has been shown to initiate a series of effects on the cycling of carbon and nitrogen, as well as a shift in the system from an aerobic environment where oxygen is readily available to an anaerobic environment where oxygen is lacking.

5- Impacts of phosphorus enrichment: periphyton community impacts.

Scientific literature describing Everglades periphyton communities, their function and the impacts of13

phosphorus include the following: Hunt, 1961; Brock, 1970; Gleason and Spackman, 1974; Wilson, 1974; Wood and Maynard, 1974; Gleason et al., 1975b; Swift and Nicholas, 1987; Flora et al., 1988; Hall and Rice, 1989; Belanger et al., 1989; Grimshaw et al., 1993; Raschke, 1993; Browder et al., 1994; Craft and Richardson, 1994; Craft et al., 1995; McCormick et al., 1996; McCormick and O'Dell, 1996; McCormick et al., 1997; Vaithiyanathan et al., 1997; Vaithiyanithan and Richardson, 1998; McCormick et al., 1999.

Periphyton is an important defining characteristic of the Everglades ecosystem.

The smallest but most widely distributed plant community in the Everglades is an assemblage of micro-algae referred to collectively as periphyton. Everglades periphyton generally is comprised of three major divisions or groups: diatoms, blue-green algae and green algae (Browder et al., 1994). Periphyton exhibits three growth forms in the Everglades: benthic (growing on the soil surface), epiphytic (growing attached to rooted vegetation) and floating (growing on the water surface sometimes in association with other floating vegetation such as Utricularia purpurea ) (McCormick et al., 1999). These periphyton mat communities are found throughout the unimpacted Everglades marsh, especially in open water areas, sloughs and wet prairies. The widespread distribution of floating periphyton mats throughout the Everglades as observed during 1995-1996 is presented by Stober et al. (1998).

The designated use for Class III-A Waters of the Tribe is “preservation of native plants and animals of the natural Everglades ecosystem”. This clearly includes preservation of natural periphyton communities, in so far as periphyton are native plants.

Periphyton provides multiple functions in the marsh ecosystem. These have been summarized by Browder et al. (1994), McCormick et al. (1998) and McCormick et al. (1999). Everglades periphyton: accounts for much of marsh primary productivity in wet prairies and sloughs; provides habitat for aquatic animals such as invertebrates; along with macrophyte detritus, forms the base of the Everglades aquatic food web; is the major source of oxygen for fish and other animal life in sloughs and wet prairies; maintains low water TP concentrations; plays a role in cycling of nitrogen, phosphorus, carbon and oxygen; and affects formation of marl soils.

Periphyton photosynthesis and respiration play an important role in controlling surface water dissolved oxygen concentrations. (Hunt, 1961; Gleason and Spackman, 1974, Wilson, 1974, Belanger et al., 1989; McCormick et al., 1997; Vaithiyanathan et al., 1997).

Vymazal et al. (1994) stated that “Highly calcified periphyton, dominated by blue-green algae, is the primary source of oxygen in open water habitats and for most of the Everglades ecosystem” (page 76).

Vaithiyanathan et al. (1997a) in a 1991-1996 study of WCA2A sloughs found that the dissolved oxygen concentration on the surface of the periphyton mat was substantially higher than the water column concentration, reflecting the intense photosynthetic activity of the Utricularia

periphyton complex. They concluded that: periphyton photosynthesis is a major source of oxygen production in Everglades sloughs, periphyton regulate water column TP concentrations, nutrient14

ratios in surface water and in the periphyton and macrophyte tissues suggest strong P-limitation, and “preservation of the Everglades sloughs is strongly related to the integrity of the periphyton mat” (page 5-22).

Belanger et al. (1989) described a 1985 oxygen budget study in enriched and unenriched marsh habitats with WCA2A. They found strong surface water diurnal oxygen variations in slough and sawgrass areas, with extremely low surface water dissolved oxygen and frequent anoxia in the enriched cattail area. The periphyton mat was the major source of oxygen at the slough site. They stated that pristine slough areas are essential for oxygen production, and loss of these areas due to phosphorus enrichment could have serious ecological consequences, such as lost feeding areas for

fishes and birds.

Numerous scientists have stated that periphyton is an integral component of the oligotrophic marsh system. In their external panel peer-review report to FDEP, Hopkinson et al. (1998, page 20) stated that “The periphyton community is a particularly important component of sloughs in the Everglades, and is often associated closely with floating macrophytes (e. g., Utricularia spp.) which serve as physical substrata for growth. Periphyton contributes a substantial portion of the primary production in the Everglades and appears to be the primary food resource for many macroinvertebrates. Periphyton may be of higher importance in Everglades food webs than macrophytes because of its high rate of production and turnover. While organic matter derived from sawgrass and other macrophytes is consumed primarily after it dies and becomes the basis of a relatively inefficient detritus-based food web, periphyton is consumed while living, providing a richer, more direct, and probably more efficient, transfer of organic matter and energy to invertebrate and vertebrate consumers. Loss of periphyton or shifts in species composition toward forms that are less palatable to consumers are likely to create a significant change in Everglades

food webs”.

Vaithiyanathan et al. (1997, page 5-1) summarized the multiple functions of periphyton and concluded that “The integrity of the periphyton mat is crucial to the protection of the Everglades slough community”.

Richardson et al. (1997, page 17-28) stated that “Any changes in Eleocharis spp. may be the most significant ecological change in the slough community since it is the dominant plant and an important substrate for periphyton.”

Grimshaw et al. (1997, page 19) stated that “Periphyton communities are critical structural and functional components of the Florida Everglade wetland ecosystem.”

McCormick and Stevenson (1998, page 730) stated that “...the loss of the oligotrophic periphyton assemblage represents a significant ecological change because periphyton represents a habitat and food source for other species as well as an important part of major biogeochemical cycles.”

The South Florida Ecosystem Restoration Task Force adopted a series of success indices in order to define ecosystem restoration goals, track ecosystem health, and measure the effectiveness of restoration efforts. The Science Sub-Group of the Task Force (1997) established 14 ecologic or15

precursor success criteria for ecosystem protection and restoration. These specific success criteria were selected based on several years of collaborative scientific effort, representing the distillation of the best professional judgement of dozens of scientists. One of the adopted ecologic success criteria is “restored natural taxonomic composition of periphyton communities”.

McCormick and O’Dell (1996, page 465) concluded: “Periphyton is an important biological component of the Everglades ecosystem and may represent one of the most sensitive indicators of eutrophication in the marsh. The periphyton assemblage that dominates oligotrophic areas of the Everglades was replaced by a taxonomically distinct assemblage in response to relatively small increases in water column phosphorus concentration above background levels, which ranged between 5 and 10 ug/L in WCA2A during this and previous work (McCormick et al., 1996). Because of its ubiquity and significance to fundamental ecosystem processes (i.e., energy fixation, nutrient cycling, and soils formation) in the Everglades, the native periphyton assemblage represents an important indicator of ecosystem condition, and its loss has several implications for the success of ecosystem restoration and management efforts in this wetland. Most importantly, our findings indicate that restoration measures must reduce and maintain phosphorus concentrations in the marsh close to background levels to preserve the oligotrophic characteristic of the Everglades.”

McCormick et al. (1998) studied periphyton biomass and productivity in WCA2A during 1994-1995. They noted many functions that periphyton communities provide, and that periphyton appears to play a critical role in sequestering phosphorus from the water column and maintaining the oligotrophic status of this wetland. They noted that eutrophication has caused a decline in Everglades periphyton biomass, productivity, and nutrient retention, and a shift in species composition. They hypothesized that functional changes resulting from this decline may affect other biotic and abiotic components of the marsh including changes in the food web, reduced suitability of eutrophic habitats for some native species, and a reduction in the capacity of the marsh to assimilate added phosphorus without causing further biological changes. They stated that (page 206) “...it is increasingly clear that the maintenance of the native periphyton assemblage is essential to the normal functioning of the Everglades and, thus, is critical to the success of efforts to restore and manage this wetland in a sustainable manner.”

Vaithiyanithan and Richardson (1998) studied the biogeochemical characteristics of two WCA-2A sloughs. They noted that the decline in periphyton mat cover reported in parts of the Everglades subjected to eutrophication will result in a decrease in the water column dissolved oxygen concentration and may also lead to other ecosystem changes by enhancing light availability to the slough bottom. They stated that increased light availability may also lead to the establishment of other macrophyte species uncharacteristic of the oligotrophic sloughs. They concluded (page 1449): “Preservation of the Everglades sloughs is thus strongly related to the integrity of the periphyton mat”.16

Phosphorus enrichment changes or eliminates the native Everglades periphyton communities

.

Increasing water column phosphorus has been repeatedly shown to cause numerous changes to the periphyton community, including changed phosphorus content, changed biomass, loss of native species such as diatoms that are indicators of oligotrophic conditions, or establishment of a different community with changed spatial extent and species composition.

Gleason et al. (1975a) investigated the effect of agricultural runoff on the periphyton communities observed at five Refuge wet prairie marsh sites during the spring of 1974. The two marsh stations in contact with agricultural runoff were distinct from the other stations with respect to diatoms, green algae, blue-green algae, and periphyton biomass and phosphorus content. They stated that the “correlation between high biomass, high phosphorus and close proximity to the peripheral canal suggests that the high biomass and high phosphorus concentrations are probably, in part, a response to higher nutrient concentrations near the rim canal.” (page 63).

Swift (1984) reported on water quality and periphyton relationships observed during 1978- 1979 throughout Loxahatchee National Wildlife Refuge and WCAs 2A and 3A. He found that periphyton growth on glass slides was significantly affected by site differences in marsh water major ion content, pH, alkalinity and phosphorus concentration. Marsh water TP was the controlling factor regulating periphyton growth. Elevated water TP increased periphyton biomass, increasedperiphyton phosphorus content, and altered community species composition toward pollutiontolerant species.

In an analysis of periphyton data collected by Swift from 1978-1983 in WCA2A, WCA3A, and WCA3B, Grimshaw et al. (1993) found strong statistically significant correlations between mean dissolved phosphorus concentrations in the marsh water column and the mean phosphorus content and mean relative abundance of eutrophic algae in periphyton communities within WCA2A. They also found statistically strong significant correlations between total, dissolved and inorganic phosphorus in the water column with the mean phosphorus content of periphyton communities

when WCA3A and WCA3B were included.

A 1983-1984 nutrient dosing study in an Everglades National Park wet prairie (Flora et al., 1988; Hall and Rice, 1990) documented changes in the algal community in response to phosphorus enrichment. An average addition of 14 ppb phosphate over a 63-day period resulted in the elimination of the native periphyton mat, which continued to remain at the adjacent reference sites that were not subjected to nutrient addition. Continued dosing caused an increase in periphyton biomass and a succession of changes in periphyton community composition. The average background phosphate

concentration for the study duration was 6 ppb.

Raschke (1993) reported the results of a 1990-1991 study of diatom community response along a soil phosphorus gradient within Everglades National Park downstream of water control structure S-12C. A strong correlation was found between sediment phosphorus concentration and diatom community mean diversity. He concluded that the periphyton diatom community was responding to sediment phosphorus increases as evidenced by changes in the number of diatom species, mean diversity, and occurrence of periphyton species that are indicators of phosphorus enrichment. The TP concentration of water discharged to the marsh through the S-12C structure17

had an annual median ranging from 7 ppb to 14 ppb during the previous 12 years. From 1978 to 1989 water TP at S-12C had increased from about 7 ppb to 12 ppb.

McCormick and O’Dell (1996) quantified periphyton responses to phosphorus in WCA2A. During 1995 they sampled transect stations along a phosphorus gradient while simultaneously performing a phosphorus enrichment experiment in a pristine slough. Phosphorus content of periphyton mats was strongly correlated with surface water TP, and periphyton mat species composition changed along the phosphorus gradient. They concluded that these changes were caused by phosphorus concentrations. McCormick and O’Dell also stated that:

“The cyanobacterial-diatom assemblage characteristic of oligotrophic conditions in the Everglades was replaced by filamentous green algae at marsh stations where water-column phosphorus concentrations exceeded 10 ug/L TP.” (page 464).

“Our study provides strong experimental evidence to support previous evidence that relatively small increases in marsh phosphorus concentration are associated with substantial changes in the Everglades periphyton assemblage.” (page 464).

“The loss of the calcareous cyanobacterial mat in response to phosphorus enrichment has ramifications for several ecosystem processes in the Everglades. This mat can account for more than 50% of the vegetative biomass in sloughs (Wood and Maynard, 1974, Browder, et al. 1982) and represents an important substrate for invertebrate populations in the marsh (Reark, 1961).” (page 465).

McCormick and O’Dell also mentioned: the role that this periphyton mat plays in maintaining surface water oxygen in the marsh, with mat absence associated with protracted periods of low dissolved oxygen or anoxia; its role in affecting availability of phosphorus and nitrogen; and its role in forming marl soils in portions of the Everglades. They stated that changes in the periphyton assemblage may have important implications for the Everglades food web.

Pan et al. (1997, page 2-13) sampled 32 sloughs in WCA2A along a phosphorus enrichmentgradient during 1995 and found that diatom species composition, periphyton biomass, and physicochemical structure of periphyton assemblages all shifted relative to native assemblages as P loading increased. “Changes in periphyton assemblages along the P gradients were evident at the community, functional, and population levels”. They also stated that changes in algal species composition are much more sensitive and predictable than algal biomass (chlorophyll a and biovolume) in response to P loading. Cluster analysis of data separated the 32 sites along the P gradient into 3 groups based on diatom species composition. Periphyton biomass and ash weight decreased and the TP content of periphyton increased as water column TP increased from group I (surface water TP mean 11.54 ppb) to group II (surface water TP mean 16.37 ppb).

McCormick and Stevenson (1998) reported data from an experiment in which several different concentrations of phosphate were added to nutrient dosing flumes as described in Richardson et al. (1994). They stated that calcareous periphyton was reduced in waters averaging 5 ug/l soluble reactive phosphorus (SRP) above the background concentration of about 4 ug/L SRP. They noted that the observed periphyton mat cover varied over time taxonomically and chemically,18

and the common characteristic of the phosphorus environment in which the calcareous mat did not exist was that SRP was at least 5 ug/L greater than the concentration in the control treatment.

In their 1999 Everglades Interim Report, SFWMD (McCormick et al., 1999) found that controlled dosing studies combined with sampling along marsh phosphorus gradients in WCA-2A indicate that periphyton species changes begin to occur at water column total phosphorus concentrations of about 10 ppb.

6- Impacts of phosphorus enrichment: water column dissolved oxygen.

Relevant scientific literature: Hunt, 1961; Gleason and Spackman, 1974; Gleason et al., 1975a; McPherson et al., 1976; Scheidt et al., 1985; Belanger and Platko, 1986; Belanger et al., 1989; McCormick et al., 1997.

Dissolved oxygen in pristine Everglades wet prairie and slough communities often exhibits a strong diel cycle, with concentration at a particular location ranging from 0 mg/l in early morning to over 12 mg/l in late afternoon. In contrast, oxygen levels in nutrient-rich locations within WCA2A have been shown to often be undetectable and rarely exceed 2 mg/l, with protracted periods of oxygen depletion. Although wetland plant and animal species are well adapted to the natural diel cycle of anoxia that often characterizes pristine marsh ecosystems, it is improbable that many native Everglades fish species are tolerant of prolonged oxygen depletion.

McCormick et al. (1997) summarized marsh diel dissolved oxygen data at minimallynutrient-impacted sites (reference sites) in WCA1, WCA2A, and WCA3A and at a phosphorusimpacted site in WCA2A. They found that all reference sites were characterized by a strong dielvariation in water column oxygen (0-12 mg/L) while oxygen concentration at the phosphorusimpacted site rarely exceeded 2 mg/L and were often undetectable. Rates of gross primary productivity and aerobic respiration were higher, with average P/R ratios near unity (1.0) at reference sites, as compared to the enriched site (P/R<0.5). Nutrient enrichment was associated with reduced primary productivity, a shift towards increasing community heterotrophy and protracted periods of oxygen depletion. They also state that the “intense photosynthetic activity of the periphyton- Utricularia mats represents the major source of aquatic O 2 production in the Everglades,...”(page 124) and the “loss of the native periphyton- Utricularia mat from enriched sloughs corresponds with a shift towards a heterotrophic system (P/R<1) and prolonged periods of

O 2 depletion (<2 mg/L) in the water column.” (page 127).

7- Impacts of phosphorus enrichment: soil.

Relevant scientific literature: Koch, 1991; Reddy et al., 1991; Koch and Reddy, 1992; Jones and Amador, 1992; Reddy et al., 1993; Craft and Richardson, 1993; Debusk et al., 1994; Qualls and Richardson, 1995; Doren et al., 1996; Walker and Kadlec, 1996; Newman et al., 1997; Craft and Richardson, 1997; Richardson et al., 1997; Vaithiyanithan and Richardson, 1997; Stober et al., 1998; Reddy et al., 1998.

Increasing water column phosphorus concentration over sufficient duration has increased19

Everglades soil phosphorus concentrations. Soil TP gradients have been documented throughout the Everglades system with the highest concentrations observed at soils downstream of structures discharging high phosphorus water. This soil enrichment phenomenon has been documented

within:

LNWR- [Richardson et al., 1990; Doren et al., 1996; Newman et al., 1997; Stober et al., 1998];

WCA2A- [Koch, 1991; Reddy et al., 1991; Koch and Reddy, 1992; Craft and Richardson, 1993; Debusk et al., 1994; Qualls and Richardson, 1995; Doren et al., 1996; Craft and Richardson, 1997; Richardson et al., 1997; Craft and Richardson, 1998; Vaithiyanithan and Richardson, 1997; Stober et al., 1998)]; WCA3A- [Doren et al., 1996; Stober et al., 1998]; and ENP- [Raschke, 1993; Doren et al., 1996; Stober et al., 1998].

Craft and Richardson (1998) studied peat soil accretion and accumulation throughout the Everglades. They found that unenriched areas of the Everglades possess some of the lowest rates of P accumulation of peatlands in North America. In enriched areas of WCA2A, phosphorus accumulation was eight times higher and soil accretion was three to five times higher than in unenriched areas. They stated that even small anthropogenic P loadings may alter organic soil accretion and nutrient accumulation. “Successful restoration of the Everglades will have to include the elimination of anthropogenic nutrient loadings to limit the P enrichment zone from expanding into existing unenriched interior areas and areas downstream of WCA2A.” (abstract)

Richardson et al. (1997) noted that the most nutrient-impacted area of the Everglades is WCA2A, with 51% of the area showing increased soil P (page 14-3).

Several investigators have documented a correlation between elevated soil TP and the expansion of cattail into sawgrass or wet prairies (see below). Walker and Kadlec (1996) developed a mass balance model to simulate phosphorus concentrations in waters and soils downstream of Everglades Stormwater Treatment Areas. They proposed a soil threshold phosphorus criteria of 540 to 990 milligrams per kilogram (mg/kg) as a surrogate for impacts on ecosystem components which respond primarily to soil P, such as cattail expansion.

8- Impacts of phosphorus enrichment: macrophyte impacts.

Relevant scientific literature: Steward and Ornes, 1975a; Steward and Ornes, 1975b; Gleason et al., 1975b; Davis, 1989; Flora et al., 1988; Walker et al., 1989; Richardson et al., 1990; Davis, 1991; Koch, 1992; Urban et al., 1993; Rutchey and Vilchek, 1994; Davis, 1994; DeBusk et al., 1994; Jensen et al., 1995; Doren et al., 1996; Walker and Kadlec, 1996; Craft and Richardson, 1997; Newman et al., 1997; Stewart et al., 1997; Stober et al., 1998; Daoust and Childers, 1999.

The oligotrophic Everglades marsh system contains a mosaic of macrophyte communities, such as sloughs, wet prairies and sawgrass marshes, all of which are adapted to low nutrient conditions. This mosaic is an important defining characteristic of the Everglades. Wet prairies and sloughs in particular provide critical habitat for animals and provide cover, nesting, and feeding sites for all animal groups. The wet prairie/slough habitat is also the major feeding area in the Everglades for both wintering and nesting wading birds, especially during the dry season when fish concentrations provide food for their nestlings (Gunderson and Loftus, 1993). An important20

characteristic of unimpacted wet prairies and sloughs is their diversity and the large number of native plant species (Olmstead et al, 1980; Olmstead and Loope, 1984; Goodrick, 1974; Gunderson and Loftus, 1993). Multiple factors are responsible for the alteration and maintenance of plant community structure in the Everglades, including nutrients, fire, disturbance, and hydroperiod. Elevated water phosphorus concentrations or elevated soil phosphorus concentrations in the Everglades are associated with elimination of submerged vegetation species including the

Utricularia- periphyton complex and expansion of nutrient-tolerant macrophytes such as cattail or Sagittaria into areas previously dominated by sawgrass, sloughs or wet prairies.

Ornes and Steward (1973) added phosphorus (10 milligrams per liter) and potassium to a WCA3B sawgrass marsh for 22 weeks in order to simulate sewage effluent discharge. They reported algal blooms and macrophyte community changes, including elimination of native submerged aquatic vegetation such as Utricularia spp.

Gleason et al. (1975b) investigated the effect of agricultural runoff on the Everglades marsh. They looked at the effect of nutrient inputs on biomass and phosphorus concentrations in cattail and sawgrass downstream of the S-10 structures within WCA2A. They noted that the two species respond differently to added nutrients and concluded that “The differential growth response of the two plant species to phosphorus enrichment offers an explanation for the invasion of sawgrass by cattail in Area 2A below the S-10 structures.” (page 115).

A 1983-1984 nutrient dosing study in an Everglades National Park wet prairie (Flora et al., 1988; Hall and Rice, 1990) documented changes in periphyton and emergent plant communities in response to phosphorus enrichment. Within one year of phosphate addition at an average concentration of 27 ppb the native Utricularia -periphyton assemblage had been eliminated and the open water marsh which was previously dominated by Eleocharis spp. became dominated by dense emergent stands of Sagittaria and Panicum. Plant tissue concentrations, biomass and community composition were all changed within several months. The background phosphate concentration for the study duration was 6 ppb.

From 1985 to 1990, Richardson et al. (1990) conducted a study of vegetation and habitats within Loxahatchee National Wildlife Refuge and their relationships to water quality, quantity and hydroperiod. Multi-variate analysis indicated that soil phosphorus rather than hydroperiod was the primary factor controlling cattail distribution in the Refuge.

Craft and Richardson (1997) studied relationships between soil nutrients and plant species (sawgrass, cattail and other species) in WCA2A during 1989. They found that plant species composition along a P enrichment gradient was highly correlated with soil P content, but not with sodium or calcium. They concluded that “P, not Na, is the primary determinant of the observed changes in macrophyte community composition in enriched areas of WCA2A” (page 231) and “These findings support previous studies, which indicate that cattail encroachment into sawgrass communities in northern WCA2A is caused, to a large extent, by P enrichment of the peat (Urban et al., 1993; DeBusk et al., 1994)” (page 232).21

Newman et al. (1997) observed the spatial distribution of soil nutrients and plant species in Loxahatchee National Wildlife Refuge during 1991. Of the 90 sites sampled, 66 sites consisted of sloughs and sawgrass, while 24 were either cattail-dominated or had a significant cattail presence. “These 24 cattail sites were closest to the nutrient inflow areas and had the highest soil nutrient concentrations” (page 1275).

From 1991-1993 Newman et al., (1996) studied the effects of nutrients (P and nitrate) and hydroperiod on cattail, sawgrass and Eleocharis in controlled outdoor tanks. Their high treatment consisted of nutrient additions to adjust ambient marsh water concentrations to 100 ppb phosphorus and 1 milligram per liter (1000 ppb) nitrogen. Their low treatment increased the ambient P concentration to 50 ppb with no adjustment made to the nitrate concentration. They observed that cattail was enhanced by both elevated nutrient concentration and increased depth of flooding. Increased nutrients led to a significant dominance of cattail over sawgrass and Eleocharis , and this dominance was further enhanced by increased flooding levels. They noted that the interaction between nutrients and hydrology is important, and that restoration of Everglades vegetation requires more natural hydroperiods as well as reduced nutrient inputs.

Grimshaw et al. (1997) compared the relative net primary productivity of periphyton communities within WCA2A under emergent plant canopies typical of enriched and unenriched Everglades habitats. The amount of photosynthetically active radiation reaching periphyton communities was reduced only by 35% in sawgrass habitats but was reduced by 85% or more in dense stands of cattail. The net primary productivity of periphyton in nutrient-rich cattail habitats was severely reduced (by about 80%) as compared to open water habitats. The plant shading effect suppressed periphyton photosynthesis.

A 1990-1996 study of WCA2A found a significant positive correlation between cattail and Sagittaria and several indicators of increased P, including soil TP (Richardson et al., 1997, page 14-28). They also found a significant negative correlation between sawgrass and soil TP as well as surface water TP. As phosphorus enrichment increased, the number of macrophyte species typical of the oligotrophic area showed a progressive decline, and nearly half of the macrophyte species widespread throughout the unenriched Everglades were absent from the two most enriched sites (page 14-44).

In a nutrient dosing study in WCA2A, Richardson et al (1997, chapter 17) found that:

Utricularia is generally not found at TP concentrations greater than 30 ppb; maximum densities of Eleocharis elongata were reached in the un-walled control channel where TP averaged close to 10 ppb; a significant relationship was found between Eleocharis cellulosa and surface water TP concentration with a significant decrease in density above 30 ppb after four years of P dosing; “elevated TP concentrations above 20 ug/L demonstrates direct or indirect effects of elevated PO4 concentrations, which inhibits the survival of U. purpurea .” (Page 17-27); “Any changes in

Eleocharis spp. may be the most significant ecological change in the slough community since it is the dominant plant and an important substrate for periphyton” (Page 17-28).

Walker and Kadlec (1996) developed a mass balance model to simulate phosphorus concentrations in waters and soils downstream of Everglades Stormwater Treatment Areas. They proposed a 0 to 10 centimeter soil threshold phosphorus criteria of 540 to 990 milligrams per22

kilogram (mg/kg) as a surrogate for impacts on ecosystem components which respond primarily to soil P, such as cattail expansion.

Wu et al. (1997) developed a probability model to test the effect of water depth and soil TP concentration on the cattail invasion of WCA2A. They proposed a soil TP concentration of 650 milligrams per kilogram as a threshold above which accelerated cattail invasion occurs.

9- Impacts of phosphorus enrichment: food web changes and loss of wading bird foraging
habitat.

Relevant scientific literature: Bancroft et al., 1992; Hoffman, 1994; Gunderson and Loftus, 1993; Fleming et al., 1994; Turner et al., in press.

Shallow, open water areas with low to moderate density emergent macrophytes are the preferred foraging habitat for Everglades wading birds. Bancroft et al. (1992) documented the importance of the Water Conservation Areas as foraging habitat for the wood stork, an endangered species. They noted that the habitats used by wood storks generally are drying ponds, wet prairies, and sloughs. The storks feed in these more open areas, where their foraging habitats are least affected by submerged or emergent vegetation.

Hoffman et al. (1994) studied wading bird foraging habitat in the Water Conservation Areas from 1985-1988. They reported that great egrets, great blue herons, white ibises and wood storks all avoided dense grass habitats, defined as continuous coverage of sawgrass, cattail, sedges, reeds or grasses. They noted the importance of perpetuating slough and wet prairie habitats for wading birds. Conversion of these open water or wet prairie plant communities to dense stands of emergent nutrient-tolerant macrophyte species such as cattail constitutes a loss of preferred wading bird foraging habitat.

Turner et al. (in press) reported that the natural condition in the Everglades is one of high periphyton standing stock, but low standing stocks of invertebrates and fish. They also reported that: enriched areas have a higher fish standing stock; “The data we present also suggest the possibility of a trophic cascade that may lead to unanticipated changes in community structure where nutrients are added” (page 20); and “Anthropogenic eutrophication in Everglades marshes will lead to the loss of distinctive ecosystem features.” (abstract).

Gunderson and Loftus (1993) presented food web diagrams for known trophic relationships among the characteristic Everglades animals with a macrophyte base ( Utricularia, Eleocharis

, sawgrass, beak rush, and Panicum ) and a detritus/periphyton base. Macrophytes, periphyton and detritus are at the bottom or base of both food webs. Invertebrates, insects, fish, birds, amphibians, reptiles and mammals are found at higher trophic levels. Everglades phosphorus enrichment has been shown to change detrital formation processes, and change periphyton and macrophyte communities. Such changes at the food web base can be expected to change inter-relationships among species across higher trophic levels.23

CONCLUSION

The Tribe has defined Class III-A waters within the Federal Reservation as "Those Tribal water bodies which are used for fishing, frogging, recreation (including airboating), and the propagation and maintenance of a healthy, well-balanced population of fish and other aquatic life and wildlife. These waters have been primarily designated for preservation of native plants and animals of the natural Everglades ecosystem." (page 19 of the Final Miccosukee Environmental Protection Code, Subtitle B, dated December 19, 1997). In the section on water quality standards

for nutrients the Tribe states: “Nutrients: In no case shall nutrient concentrations of Tribal Class I or Class III-A surface waters be altered so as to cause an imbalance in natural populations of aquatic flora or fauna.” (page 9).

There is no single scientific study or publication that provides a complete synthesis of the data and information regarding background Everglades phosphorus conditions and phosphorus enrichment impacts. Rather, a great number of scientific publications and efforts provide relevant pieces of information, which when considered collectively, provide a generally consistent and more complete understanding.

The scientific information summarized above has been independently developed by different scientists, in different studies, over different time frames, using different methods, in different areas of the Everglades system. These scientists include consultants and individuals employed by but not limited to SFWMD, USDA, NPS, USFWS, USEPA, USGS, Florida International University, University of Florida, and Duke University. Generally, the results are complementary and corroborative. There is no question that phosphorus enrichment in the Everglades causes direct and indirect changes within this marsh ecosystem. Taken as a whole, these collective changes must be reasonably viewed as systemic. That is, phosphorus enrichment at a marsh location changes not only surface water phosphorus concentrations, but eventually also impacts plants and animals at that location. The natural structure and function of the Everglades system becomes lost. Such changes are directly contrary to the intent of the Class III-A designated use adopted by the Tribe.

The nutrient dosing studies and observational studies reviewed indicate that total phosphorus concentrations above 10 ppb have been shown to cause impacts to native Everglades periphyton and macrophytes such as Utricularia purpurea that are adapted to low phosphorus conditions. The best available scientific information indicates that average TP concentrations greater than 10 ppb, in general, can be expected to be inadequate for long-term protection of the designated use defined by the Tribe. Therefore the Tribe’s adopted numeric phosphorus criterion of 10 ppb is not overly protective.

The currently available data and information also indicates that the Tribe’s adopted numeric phosphorus criterion of 10 ppb is protective of the Class III-A designated use. While in certain portions of the Everglades system, long-term phosphorus concentrations are less than 10 ppb, the scientific information reviewed did not demonstrate that a numeric phosphorus criterion of 10 ppb would not be protective of the Class III-A designated use. For example, as summarized by Walker (1995), the long-term phosphorus concentration at wet prairie marsh station P-37 with Everglades National Park was 5.2 ppb. For WCA-3A, the SFWMD identified a total phosphorus median concentration of 5 ppb of phosphorus (McCormick et al., 1999). However, EPA’s review24

identified no currently available published scientific information documenting changes in the natural flora or fauna of the Everglades System as a result of changes in the phosphorus concentrations in the 5 ppb to 10 ppb range. If new data or scientific information are presented that demonstrate that 10 ppb is not protective of the Class III-A designated use, then the Tribe should revise the 10 ppb standard accordingly.

In conclusion, the Miccosukee Tribe’s 10 ppb criterion for phosphorus meets the requirements of 40 CFR §131.11 as it is protective of the Class III-A designated use and review of available data shows that this value is scientifically defensible.APPENDIX B1 EVERGLADES NUTRIENT-RELEVANT REFERENCES Compiled by D. Scheidt, USEPA, May 1999

Abtew, Wossenu. 1996. Evapotranspiration measurements and modeling for three wetland systems in

South Florida. Water Resources Bulletin , 32(3):465-473.

Abtew, Wossenu. 1997. Lysimeter study of evapotranspiration from a wetland. South Florida Water Management District Department of Research Publication #274. West Palm Beach, Florida. 7 pp.

Abtew, W. and J. Obeysekera. 1994. Evapotranspiration of cattails ( Typha domingensis ). South Florida Water Management District Water Department of Research Publication #147. West Palm Beach, Florida. 21 pp. plus figures.

Abtew, Wossenu, and Nagendra Khanal. 1994. Water Budget Analysis for the Everglades Agricultural Area Drainage Basin. Water Resources Bulletin 30:429-439.

Abtew, W., M. Chimney, T. Kosier, M. Guardo and J. Obeysekera. 1995. The Everglades Nutrient Removal Project: A Constructed wetland designed to treat agricultural runoff/drainage. pp. 45-56 in “Versatility of wetlands in the agricultural landscape”, Kenneth Campbell, editor. Published by the American Society of Agricultural Engineers.

Abtew, W., S. Newman, K. Pietro, and T. Kosier. 1995. Canopy Resistance Studies of Cattails. Transactions of the American Society of Agricultural Engineers 38(1):113-119.

Abtew, W., M. Chimney, and T. D. Fontaine. 1996. Particulate Phosphorus Fraction and Total Suspended Solids Role in P Removal Strategy in the Inflow Waters of the Everglades. Paper No. 962128 written for presentation at the 1996 ASAE Annual International meeting, July 14-18, 1998, Phoenix, Arizona. South Florida Water Management District. 12 pp.

Abtew, W., L. J. Lindstrom, and T. Bechtel. 1997. A Comparison of methods for estimating the mean and variance of censored total phosphorus concentrations in South Florida rain. South Florida Water Management District Technical Manuscript #352. West Palm Beach, Florida 33 pp.

Abtew, W., A. Cadogan, A. Ali, T. Kosier, G. Germain and D. Wilkins. 1998. Hydrologic Performance of an Everglades Stormwater Treatment Area- STA6: A Constructed Wetland. South Florida Water Management District Water Resources Evaluation Publication #362. West Palm Beach, Florida. 12 pp.

Ahn, Hosung. 1998. Estimating the mean and variance of censored phosphorus concentrations in Florida

rainfall. Journal of the American Water Resources Association 34(3):583-593.

Ahn, Hosung. 1998. Statistical Modeling of Total Phosphorus Concentrations measured in South Florida Rainfall. South Florida Water Management District Technical Manuscript #358. West Palm Beach, Florida. 20 pp. plus figures.

Ahn, Hosung. 1998. Outlier detection in total phosphorus concentration data from South Florida rainfall. South Florida Water Management District Technical Manuscript #359. West Palm Beach, Florida. 18 pp. plus figures2

Alexander, Taylor and Alan Crook. 1984. Recent vegetational changes in southern Florida. pp. 199-210 in “Environments of South Florida: Present and Past II”. Patrick Gleason, editor. Miami Geological Society, Coral Gables, Florida. 551 pp.

Amador, J. A., and R. D. Jones. 1993. Nutrient Limitation on Microbial Respiration in Peat Soils with Different Total Phosphorus Content. Soil Biol. Biochem. 25:793-801.

Amador, J. A., and R. D. Jones. 1995. Carbon mineralization in pristine and phosphorus-enriched peat soils of the Florida Everglades. Soil Science 159(2):129-141.

Amador, Jose A., G. Hafiza Richany, and Ronald D. Jones. 1992. Factors Affecting Phosphate Uptake by Peat Soils of the Florida Everglades. Soil Science 153:463-470.

Anderson, D. and R. B. Beverly. 1985. The effects of drying upon extractable phosphorus, potassium and bulk density of organic and mineral soils of the Everglades. Soil. Sci. Soc. Am. J . 49:362-366.

Anderson, D. L. And E. G. Flaig. 1995. Comprehensive Water Management in South Florida: Agricultural Best Management Practices and Surface Water Improvement and Management. Water Sci.

Tech . 31(8):109-121.

Andrews, Ralph. Undated. Appendix I. Vegetative cover-types of Loxahatchee and their principal components. U. S. Fish and Wildlife Service Branch of Refuges. 10 pp.

Bachoon, D. and R. Jones. 1992. Potential Rates of Methanogenesis in Sawgrass Marshes with Peat and Marl Soils in the Everglades. Soil Biology and Biochemistry 24:21-27.

Bancroft, G. Thomas, Wayne Hoffman, Richard J. Sawicki and John C. Ogden. 1992. The Importance of the Water Conservation Areas in the Everglades to the Endangered Wood Stork ( Mycteria amerciana ). Conservation Biology 6(3):392-398.

Bartow, Susan M., Christopher B. Craft, Curtis J. Richardson. 1996. Reconstructing Historical Changes in Everglades Plant Community Composition Using Pollen Distributions in Peat. Journal of Lake and Reservoir Management . 12(3): 313-322.

Bates, Anne, Elliott Spiker and Charles Holmes. 1998. Speciation and isotopic composition of sedimentary sulfur in the Everglades, Florida, USA. Chemical Geology 146:155-170.

Bechtel, Timothy, Steven Krupa, Steve Hill and Richard Xue. 1996. Evaluation of Water Quality Criteria in the Everglades Protection Area. Submitted to Florida DEP in support of the Everglades Program Management Plan Research and Monitoring Project 3 (RAM-3). South Florida Water Management District, West Palm Beach, Florida. 77 pp. plus appendices.

Bechtel, Timothy J. and Steven D. Hill. 1996. Analysis of Historical Water Quality Data for Non-ECP Structures S-9, S-140, S-142, S-175, S-190, S-332, G-94D and the C-111 Gaps. February 9, 1996 Draft. South Florida Water Management District. 58 pp.

Bechtel, Timothy, Steven Hill, Nenad Iricanin, Kimberly Jacobs, Cheol Mo, Victor Mullen, Richard Pfeuffer, David Rudnick and Stuart Van Horn. 1999. Status of Compliance with Water Quality Criteria in the Everglades Protection Area and tributary waters. Chapter 4 in “Everglades Interim Report”. South Florida Water Management District. West Palm Beach, Florida. 132 pp.3

Bechtel, Timothy and Cheol Mo. 1998. Total Phosphorus Load Calculations for Sites Stipulated in the SFWMD/Seminole Tribe Agreement. Final Third Semiannual Progress Report. September 4, 1998. SFWMD Resource Assessment Division, Water Resources Evaluation Department. Submitted to SFWMD/Seminole Tribe Agreement Working Group. West Palm Beach, Florida. 79 pp.

Belanger, T. V., D. J. Scheidt, and J.R. Platko II. 1989. Effects of Nutrient Enrichment on the Florida Everglades. Lake and Reservoir Management 5:101-111.

Belanger, T. and J. Platko II. 1986. Dissolved Oxygen Budgets in the Everglades WCA2A. Report to South Florida Water Management District. 112 pp.

Bottcher, A. B. And F. T. Izuno (editors). 1994. Everglades Agricultural Area: Water, Soil, Crop and Environmental Management. University Press of Florida. Gainesville, Florida. 322 pp.

Brezonick, Patrick and Anthony Federico. 1975. Effects of backpumping from agricultural drainage canals on water quality in Lake Okeechobee. Report to the Florida Department of Pollution Control for the Special project to prevent eutrophication of Lake Okeechobee. Florida Department of Environmental Regulation Technical Series volume 1, number 1. University of Florida. Gainesville, Florida. 64 pp.

Brock, Thomas D. 1970. Photosynthesis by algal epiphytes of Utricularia in Everglades National Park.

Bull. Mar. Sci. 20(4):952-956.

Browder, Joan A., S. Black, P. Shroeder, M. Brown, M. Newman, D. Cottrell, D. Black, R. Pope and P. Pope. 1981. Perspective on the Ecological Causes and Effects of the Variable Algal Composition ofSouthern Everglades Periphyton. Everglades National Park South Florida Research Center Publication T643. Homestead, Florida. 110 pp.

Browder, Joan A., D. Contrell, M. Brown, M. Newman, R. Edwards, J. Yuska, M. Browder, and J. Krakoski. 1982. Biomass and Primary Production of Microphytes and Macrophytes in Periphyton Habitats of the Southern Everglades. Everglades National Park South Florida Research Center Publication T-662. Homestead, Florida. 49 pp.

Browder, Joan A., Patrick J. Gleason and David R. Swift. 1994. Periphyton in the Everglades: Spatial Variation, Environmental Correlates and Ecological Implications. pp. 379-418 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, (eds). St. Lucie Press, Delray Beach,

Florida.

Burke, Roger A., Jr., Timothy R. Barber, and William M. Sackett. 1988. Methane Flux and Stable Hydrogen and Carbon Isotope Composition of Sedimentary Methane from the Florida Everglades. Global Biogeochemical Cycles 2:329-340.

Burns and McDonnel. 1992. Historical Phosphorus loads for the Everglades Agricultural Area. Everglades Protection Project, Palm Beach County, Florida. December 1992. Report to South Florida Water Management District.

CH2MHill, Inc. 1978. Water Quality Studies in the Everglades Agricultural Area of Florida. 80 pp.

CH2MHill, Inc. 1979. Phase 3 water quality studies in the Everglades Agricultural Area of Florida. Submitted to the Florida Sugar Cane League. April 1979. CH2M HILL, Inc. Gainesville, Florida.4

Chimney, Michael J. 1998. Effectiveness and Optimization of Stormwater Treatment Areas for Phosphorus Removal. September 9, 1998 Review Draft. Chapter 6 in the Everglades Forever Act Report to the Florida Legislature. South Florida Water Management District. West Palm Beach, Florida. 29 pp.

Coale, F. J., F. T. Izuno, and A. B. Bottcher. 1994a. Phosphorus in Drainage Water from Sugarcane in the Everglades Agricultural Area as Affected by Drainage Rate. J. Environ. Qual. 23:121-126.

Coale, F. J., F. T. Izuno, and A. B. Bottcher. 1994b. Sugarcane Production Impact on Nitrogen and Phosphorus in Drainage Water from an Everglades Histosol. J. Environ. Qual. 23:116-120.

Cohen, Arthur D. and William Spackman, Jr. 1984. The petrology of peats from the Everglades and coastal swamps of southern Florida. pp. 352-374 in “Environments of South Florida: Present and Past II”. Patrick Gleason, editor. Miami Geological Society, Coral Gables, Florida. 452 pp.

Craft, C. B., and C. J. Richardson. 1993a. Peat Accretion and Phosphorus Accumulation along a Eutrophication Gradient in the Northern Everglades. Biogeochemistry 22:133-156.

Craft, C. B., and C. J. Richardson. 1993b. Peat Accretion and N, P, and Organic C Accumulation in Nutrient-Enriched and Unenriched Everglades Peatlands. Ecological Applications 3:446-458.

Craft, C. B., J. Vymazal and C. J. Richardson. 1995. Response of Everglades Plants Communities to Nitrogen and Phosphorus Additions. Wetlands 15(3):258-271.

Craft, C. B. and C. J. Richardson. 1997. Relationships between Soil Nutrients and Plant Species Composition in Everglades Peatlands. J. Environ. Qual . 26:224-232.

Craft, C. B. and C. J. Richardson. 1998. Recent and long-term organic soil accretion and nutrient accumulation in the Everglades. Soil Sci. Soc. Am. J. 62:834-843.

Daoust, Robert J. and Daniel L. Childers. 1998. Quantifying aboveground biomass and estimating net above ground primary production for wetland macrophytes using a non-destructive phenometric technique. Aquatic Botany (62):115-133.

Daoust, Robert J. and Daniel L. Childers. 1999. Controls on emergent macrophyte composition, abundance, and productivity in freshwater Everglades wetland communities. Wetlands 19(1):262-275.

David, Peter. 1996. Changes in WCA 3A Plant Communities Relative to Hydrologic Conditions in the Florida Everglades. Wetlands 16(1):15-23.

Davis, John H., Jr. 1943. The natural features of southern Florida, especially the vegetation, and the Everglades. Florida Geological Survey Bulletin 25. Tallahassee, Florida. 311 pp.

Davis, Steven M. 1982. Patterns of Radiophosphorus Accumulation in the Everglades After its Introduction into Surface Water. South Florida Water Management District Technical Publication 82-2. West Palm Beach, Florida. 28 pp.

Davis, Steven M. 1984. Cattail Leaf Production, Mortality, and Nutrient Flux in Water Conservation Area 2A. South Florida Water Management District Technical Publication 84-8. West Palm Beach, Florida. 40 pp.5

Davis, Steven M. 1989. Sawgrass and Cattail Production in Relation to Nutrient Supply in the Everglades. pp. 325-341 in "Freshwater Wetlands and Wildlife", CONF-860301, DOE Symposium Series No. 61, R. R. Scharitz and J. W. Gibbons (eds.), USDOE Office of Scientific and Technical Information, Oak Ridge, Tennessee.

Davis, Steven M. 1990. Growth, Decomposition, and Nutrient Retention of Sawgrass and Cattail in the Everglades. South Florida Water Management District Technical Publication 90-03. West Palm Beach, Florida. 26 pp.

Davis, Steven M. 1991. Growth, Decomposition, and Nutrient Retention of Cladium jamaicense Crantz

and Typha domingensis Pers. in the Florida Everglades. Aquatic Botany 40:203-224.

Davis, S. M. 1994. Phosphorus inputs and Vegetation Sensitivity in the Everglades. pp. 357-378 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach, Florida.

Davis, S. M and L. A. Harris. 1978. Marsh plant production and phosphorus flux in Everglades Conservation Area 2. pp. 171-181 In Drew, M. A. (Ed.) “Environmental quality through wetlands utilization”, symposium proceedings, restoration of the Kissimmee River and Taylor Creek-Nubbin Slough Basin. Tallahassee, Florida.

Davis, Steven, Lance Gunderson, Ronald Hofstetter, David Swift and Bradley Waller. 1987. An Assessment of the Potential Benefits to the Vegetation and Water Resources of Everglades National Park and the Southern Everglades Ecosystem Associated with the General Design Memorandum to Improve Water Deliveries to Everglades National Park. Statement Paper. 20 pp.

Davis, Steven M., and John C. Ogden. 1994. Toward Ecosystem Restoration. pp 769-796 in Everglades: The Ecosystem and Its Restoration . S. Davis and J. Ogden, editors. St. Lucie Press, Delray Beach, FL. 848 pp.

Davis, S. M, L. Gunderson, W. Park, J. Richardson, Jr., and J. Mattson. 1994. Landscape dimension, Composition, and function in a changing Everglades Landscape. pp. 419-443 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach,

Florida

DeBusk, W. F., K. R. Reddy, M. S. Koch, and Y. Wang. 1994. Spatial Distribution of Soil Nutrients in a Northern Everglades Marsh: Water Conservation Area 2A. Soil Sci. Soc. Am. J. 58:543-552.

Diaz, O. A., D. L. Anderson, and E. A. Hanlon. 1993. Phosphorus Mineralization from Histosols of the Everglades Agricultural Area. Soil Science 156:178-185.

Dickson, Kevin G., A. Federico and J. Lutz. 1978. Water Quality in the Everglades Agricultural Area and its impact on Lake Okeechobee. South Florida Water Management District Technical Publication 78-03. West Palm Beach, Florida. 132 pp.

Dineen, J. Walter. 1972. Life in the tenacious Everglades. In Depth Report volume 1, number 5, May, 1972. Central and Southern Florida Flood Control District. West Palm Beach, Florida. 12 pp.6

Doren, Robert F., Thomas V. Armentano, Louis D. Whiteaker, and Ronald D. Jones. 1996. Marsh Vegetation Patterns and Soil Phosphorus Gradients in the Everglades Ecosystem. Aquatic Botany 56:145-

163.

Doren, Robert F., Ken Rutchey and Roy Welch. 1999. The Everglades: A Perspective on the Requirements and Applications for Vegetation Map and Database Products. Photogrammetric Engineering and Remote Sensing 65(2):155-161.

Duxbury, John M. and Robert L. Tate III. 1981. The effect of soil depth and crop cover on enzymatic

activities in Pahokee muck. Soil Sci. Soc. Am. J . 45:322-328.

Engelhardt, James D. 1996. Draft Benefit-risk analysis of Everglades Stormwater Treatment Area Phase I Discharge Alternatives. University of Miami. Coral Gables, Florida. 22 pp.

Environmental Science and Engineering, Inc. 1993. Western Basins Environmental Assessment. Report Number 6: Water Quality Assessments. Prepared for South Florida Water Management District. ES&E, Inc. Sarasota, Florida

Federico, Anthony, Paul Millar and Frederick Davis. 1984. Water Quality and Nutrient Loading Analysis of the Water Conservation Areas 1978-1983. For South Florida Water Management District, Water Chemistry Division, Resource Planning Department. 195 pp. + Figures.

Fitz, Carl and Fred Sklar. 1998. Ecosystem analysis of phosphorus impacts and altered hydrology in the Everglades: a landscape modeling approach. South Florida Water Management District Department of Research Publication 321. West Palm Beach, Florida

Fitz, H. Carl, Robert Costanza and Alexey Voinov. 1998. A dynamic spatial model as a tool for integrated assessment of the Everglades, USA. SFWMD Department of Research Publication 309. West Palm Beach,

Florida

Fleming, D. M., W. W. Wolff, and D. L. DeAngelis. 1994. Importance of Landscape Heterogeneity to Wood Storks in Florida Everglades. Environmental Management 18(5):743-757.

Flora, Mark D. And Peter C. Rosendahl. 1982. An Analysis of Surface Water Nutrient Concentrations in the Shark River Slough, 1972-1980. Everglades National Park South Florida Research Center Publication T-653. Homestead, Florida. 40 pp.

Flora, Mark D. And Peter C. Rosendahl. 1982. Specific conductance and ionic characteristics of the Shark River Slough, Everglades National Park, Florida. Everglades National Park South Florida Research Center Publication T-615. Homestead, Florida. 55 pp.

Flora, Mark D. and P. C. Rosendahl. 1982. The response of specific conductance to environmental conditions in the Everglades National Park, Florida. Water, Air and Soil Pollution 17:51-59.

Flora, Mark D. and Peter C. Rosendahl. 1982. The impact of atmospheric deposition on the water quality of Everglades National Park. pp. 55-61 in “Proceedings of the American Water Resources Association International Symposium on Hydrometeorology”. Bethesda, Maryland.

Flora, Mark D., David R. Walker, Kenneth A. Burgess, Daniel J. Scheidt and Ramona G. Rice. 1986. The Response of Experimental Channels in Everglades National Park to Increased Nitrogen and Phosphorus7

Loading. Data Report: Chemistry and Primary Productivity. National Park Service Water Resources Report No. 86-6. NPS Water Resources Division. Fort Collins, Colorado. 56 pp.

Flora, Mark D., David R. Walker, Daniel J. Scheidt, Ramona G. Rice, and Dixon H. Landers. 1988. The Response of the Everglades Marsh to Increased Nitrogen and Phosphorus Loading, Part I: Nutrient Dosing, Water Chemistry, and Periphyton Productivity. Report to the Superintendent. Everglades National Park, Homestead, FL. 61 pp.

Florida Department of Environmental Regulation. 1987. Water Quality Data Assessment of South Florida Water Conservation Areas. Tallahassee, Florida 50 pp.

Frederick, P. C. and M. G. Spalding. 1994. Factors Affecting Reproductive Success of Wading Birds (Ciconiiformes) in the Everglades Ecosystem. pp. 659-692. In "Everglades: the Ecosystem and its restoration". S. M. Davis and J. C. Ogden (Eds). St. Lucie Press.

Freiberger, Herbert J. 1972. Nutrient Survey of Surface Waters in Southern Florida During a Wet and Dry season September 1970 and March 1971. USGS Open File Report 72008. Tallahassee, Florida. 28 pp.

Freiberger, Herbert J. 1973. Effects of Backpumping from South New River Canal at Pump Station S-9 on Quality of Water in Water Conservation Area 3, Broward County, Florida. Prepared by U.S. Geological Survey in cooperation with Central and southern Florida Flood Control District and Bureau of Geology, Florida Department of Natural Resources, Tallahassee, Florida. USGS Open File Report 73026. Tallahassee, Florida. 64 pp.

Germain, Guy J. and Jonathan E. Shaw. 1988. Surface Water Quality Monitoring Network South Florida Water Management District. South Florida Water Management District Technical Publication 88-3. West Palm Beach, Florida.

Germain, Guy J. 1994. Surface Water Quality Monitoring Network South Florida Water Management District. South Florida Water Management District Department of Research Publication 317. West Palm Beach, Florida. 236 pp.

Germain, Guy J. 1998. Surface Water Quality Monitoring Network South Florida Water Management District. South Florida Water Management District Department of Research Publication 356. West Palm Beach, Florida. 261 pp.

Givens, L. S. 1956?. Water level management: its effect on the ecology, wildlife and fisheries resources of Loxahatchee Refuge. USFWS report. 23 pp.

Gleason, Patrick J. 1974. Chemical Quality of Water in Conservation Area 2A and Associated Canals. South Florida Water Management District Technical Publication 74-1. West Palm Beach, Florida. 72 pp. Plus appendices.

Gleason, Patrick, Peter Stone and Morris Rosen. 1974a. The Origin and Characteristics of Gyttja in Conservation Area 2A. South Florida Water Management District. West Palm Beach, Florida. 30 pp.

Gleason, Patrick, Peter Stone and Moris Rosen. 1974b. Nutrient Uptake and Rates of Nutrient Deposition in Conservation Area 2A. CSFFCD Environmental Sciences Division. West Palm Beach, Florida. 61 pp. plus appendices.8

Gleason, Patrick and William Spackman, Jr. 1974. Calcareous periphyton and water chemistry in the Everglades. Pp. 146-181 in “Environments of South Florida: Present and Past II“ Miami Geological Society, Coral Gables, Florida. 452 pp.

Gleason, Patrick, Peter Stone, David Hallett and Morris Rosen. 1975a. Preliminary Report on the Effect of Agricultural Runoff on the Periphytic Algae of Conservation Area 1. South Florida Water Management District. West Palm Beach, Florida. 69 pp.

Gleason, Patrick, Peter A. Stone, Peter Rhoads, Steven M. Davis, Michael Zaffke, Linda Harris. 1975b. The impact of agricultural runoff on the Everglades marsh located in the Conservation Areas of the Central and Southern Florida Flood Control District. CSFFCD Resource Planning Department, West Palm Beach, Florida. 119 pp. plus appendices.

Gleason, Patrick and P. Stone. 1994. Age, origin and Landscape Evolution of the Everglades Peatland. Pp. 149-197 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach, Florida.

Goodrick, Robert L. 1984. The wet prairies of the Northern Everglades. Pp. 185-190 in “Environments of South Florida: Present and Past II“ Miami Geological Society, Coral Gables, Florida. 551 pp.

Goolsby, D. A. H. C. Mattraw, A. G. Lamonds, D. V. Maddy and J. R. Rollo. 1976. Analysis of historic Water Quality data and description of plan for a sampling network in central and southern Florida. USGS water Resources Investigation 76-52. Tallahassee, Florida. 124 pp.

Gordon, A. S., W. J. Cooper, and D. J. Scheidt. 1986. Denitrification in Marl and Peat Sediments in the Florida Everglades. Applied and Environmental Microbiology 52:987-991.

Goslee, Sarah and Curtis Richardson. 1997. Establishment and seedling growth of sawgrass and cattail from the Everglades. Chapter 13 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997. Duke Wetland Center Publication 97-05.

Gough, L., R. Kotra, C. Holmes, P. Briggs, J. Crock, D. Fey, P. Hageman and A. Meier. 1996. Chemical analysis results for mercury and trace elements in vegetation, water and organic-rich sediments, South Florida. USGS Open File Report 96-091.

Gray, Susan and Gregory Coffelt. 1998. Supplemental technologies for treating Stormwater Discharges into the Everglades Protection Area. September 9, 1998 Review Draft. Chapter 8 in the Everglades Forever Act Report to the Florida Legislature. South Florida Water Management District. West Palm Beach, Florida. 19 pp.

Grimshaw, Herbert J., Morris Rosen, David R. Swift, Kevin Rodberg, and Jill M. Noel. 1993. Marsh Phosphorus Concentrations, Phosphorus Content and Species Composition of Everglades Periphyton

Communities. Arch. Hydrobiol. 128:257-276.

Grimshaw, H., R. G. Wetzel, M. Brandenburg, K. Segerblom,L. J. Wenkert, G. Marsh, W. Charnetsky, J. E. Haky and C. Carraher. 1997. Shading of periphyton Communities by Wetland Emergent Macrophytes: Decoupling of algal photosynthesis from microbial nutrient retention. Arch Hydrobiol . 139(1):17-279

Guardo, M., L. Fink, T. Fontaine, S. Newman, M. Chimney, R. Bearzotti and G. Goforth. 1995. Largescale constructed wetlands for nutrient removal from stormwater runoff: An Everglades restoration project. Environmental Management 19(6):879-889.

Gunderson, Lance H. 1994. Vegetation of the Everglades: Determinations of Community Composition. pp. 323-340 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach, Florida.

Gunderson, Lance. H., David P. Brannon and Gary Irish. 1986. Vegetation Cover Types of Shark River Slough, Everglades National Park, derived from LANDSAT thematic mapper data. Everglades National Park South Florida Research Center Publication SFRC-86/03. Homestead, Florida. 6 pp.

Gunderson, Lance H., and William F. Loftus. 1993. The Everglades. pp. 199-255 (Chapter 6) in "Biodiversity of the Southeastern United States: Lowland" . John Wiley & Sons, Inc.

Gunderson, Lance H. and James R. Snyder. 1994. Fire patterns in the southern Everglades. pp. 291-305 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach, Florida.

Hall, Greenville B. and Ramona G. Rice. 1988. The Response of the Everglades Marsh to Increased Nitrogen and Phosphorus Loading- Part III: Periphyton Community Dynamics. 43 pp. plus appendices.

Hendry, C. D., P. L. Brezonik and E. S. Edgerton. 1981. Atmospheric Deposition of Nitrogen and Phosphorus in Florida. pp. 199-215 in "Atmospheric Pollutants in Natural Waters", S. J. Eisenreich, Ed. Ann Arbor Science, Ann Arbor, Michigan.

Herndon, Alan, Lance Gunderson, and John Stenberg. 1991. Sawgrass ( Cladium Jamaicense ) Survival in a Regime of Fire and Flooding. Wetlands 11:17-27.

Hoffman, W., G. T. Bancroft and R. J. Sawicki. 1994. Foraging Habitat of Wading Birds in the Water Conservation Areas of the Everglades. pp. 585-614 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, editors. St. Lucie Press, Delray Beach, Florida.

Hoffstetter, Ronald H. and Charles Hilsenbeck. 1980. Vegetation studies of the East Everglades. Final Report to Metropolitan Dade County, Miami, Florida. University of Miami Department of Biology. Coral Gables, Florida. 109 pp.

Hoffstetter, Ronald. 1984. The effect of fire on the pineland and sawgrass communities of southern Florida. Pp. 465-476 in “Environments of South Florida: Present and Past II”. Patrick Gleason, editor. Miami Geological Society, Coral Gables, Florida. 452 pp.

Hopkinson, Charles S. Jr., Patrick Mulholland, Lawrence Pomeroy, Robert Twilley and Dennis Whigham. 1998. External Panel Report to the Florida Department of Environmental Protection: Overview and Evaluation of Everglades Nutrient Threshold Research for the period October, 1996 to October, 1997. 47

pp.

Hunt, Burton P. 1961. A Preliminary survey of the physico-chemical characteristics of Taylor Slough with Estimates of Primary Productivity. University of Miami, Department of Zoology. 26 pp.10

Hurley, J., D. Krabbenhoft, L. Cleckner, M. Olsen, G. Aiken and P. Rawlick, Jr. 1998. System Controls on the Aqueous Distribution of Mercury in the Florida Everglades. Biogeochemistry (40):293-311.

Irwin, G. A. and R. T. Kirkland. 1980. Chemical and physical characteristics of precipitation at selected sites in Florida. USGS Water Resources Investigation 80-81. Tallahassee, Florida. 74 pp.

Jensen, J. R., K. Rutchey, M. S. Koch and S. Narumalani. 1994. Inland Wetland Change Detection in the Everglades Water Conservation Area 2A Using a Time Series of Normalized Remotely Sensed Data. Submitted manuscript. Department of Research Report 140. South Florida Water Management District.

West Palm Beach Florida.

Izuno, F. T., A. Bottcher, F. J. Coale, W. A. Davis, D. B. Jones, C. F. Miller, M. Omary, K. R. Reddy, C. A. Sanchez, and L. A. Taylor. 1991. The effects of on-farm agricultural practices in the organic soils of the EAA on nitrogen and phosphorus transport. Final Report. University of Florida Institute of Food and Agricultural Sciences. Gainesville, Florida. 302 pp.

Izuno, F. T., C. A. Sanchez, F. J. Coale, A. B. Bottcher, and D. B. Jones. 1991. Phosphorus Concentrations in Drainage Water in the Everglades Agricultural Area. J. Environ. Qual. 20:608-619.

Izuno, Forrest and A. B. Bottcher. 1992. Implementation and verification of BMPs for reducing P loading in the EAA: Phase I. Submitted to the Everglades Agricultural Area Environmental Protection District. University of Florida Institute of Food and Agricultural Services. Gainesville, Florida. 86 pp.

Jensen, John R., Ken Rutchey, Marguerite Koch and Sumil Narumalan1. 1995. Inland Wetland Change Detection in the Everglades Water Conservation Area 2A Using a time series of Normalized Remotely

Sensed Data. Photogrammatic Engineering and Remote Sensing 61(2):199-209.

Jordan, Frank, Howard Jelks, and Wiley Kitchens. 1997. Habitat Structure and Plant Community Composition in a Northern Everglades Wetland Landscape. Wetlands 17(2):275-283.

Jones, Ronald D. 1996. Phosphorus cycling. Pp. 343-348 In: G. J. Hurst, G. A. Knudsen, M. J. McInerney, L. D. Stetzenbach and M. V. Walter (eds), “Manual of Environmental Microbiology”. ASM Press, Washington, D. C.

Jones, Ronald D., and Jose A. Amador. 1992. Removal of Total Phosphorus and Phosphate by Peat Soils of the Florida Everglades. Can. J. Fish. Aquat. Sci. 49:577-583.

Jones, R., J. Trexler, D. L. Childers, B. Fry, D. Kuhn, D. Lee, J. Meeder, S. Oberbauer, J. Richards, L. Richardson, M. Ross, M. Bothwell, D. Meeter and R. Ulanowicz. 1995. Numerical interpretation of Class III narrative nutrient water criteria for Everglades wetlands: Project Scope of Work. Florida International University Southeast Environmental Research Program. Miami, Florida. 75 pp. plus appendices

Kadlec, Robert H. and Susan Newman. 1992. Phosphorus removal in wetland treatment areas: principles and data. South Florida Water Management District Department of Research Publication 106. West Palm Beach, Florida.

King, Gary M., Peter Roslev, and Henrik Skovgaard. 1990. Distribution and Rate of Methane Oxidation in Sediments of the Florida Everglades. Applied and Environmental Microbiology 56:2902-2911.

Klein, Howard, J. T. Armbruster, B. F. McPherson, and H. J. Freiberger. 1975. Water and the South11

Florida Environment. USGS Water Resources Investigation 24-75. Tallahassee, Florida. 165 pp.

Koch, Marguerite S. 1991. Soil and Surface Water Nutrients in the Everglades Nutrient Removal Project. Technical Publication 91-04, DRE 302. South Florida Water Management District, West Palm Beach, Florida. 57 pp.

Koch, M. S., and K. R. Reddy. 1992. Distribution of Soil and Plant Nutrients along a Trophic Gradient in the Florida Everglades. Soil Sci. Soc. Am. J. 56:1492-1499.

Koch, M. S., and P. S. Rawlik. 1993. Transpiration and Stomatal Conductance of Two Wetland Macrophytes ( Cladium Jamaicense and Typha Domingensis ) in the Subtropical Everglades. American Journal of Botany 80:1146-1154.

Koch-Rose, M. S., K. R. Reddy, and J. P. Chanton. 1994. Factors Controlling Seasonal Nutrient Profiles in a Subtropical Peatland of the Florida Everglades. Journal of Environmental Quality 23:526-533.

Kolipinski, Milton C. and Aaron L. Higer. 1969. Some aspects of the effects of the quantity and quality of water on biological communities in Everglades National Park. United States Geological Survey Open File report 69007. Tallahassee, Florida. 97 pp.

Kushlan, James. A. 1979. Temperature and oxygen in an Everglades alligator pond. Hydrobiologia 67(3):267-271.

Kushlan, James A. and Burton P. Hunt. 1979. Limnology of an Alligator Pond in South Florida. Florida

Scientist 42(2):65-84.

Lake Okeechobee Technical Advisory Council (LOTAC) II. 1988. Volume II. Interim Report to the Governor, State of Florida Legislature. South Florida Water Management District, West Palm Beach,

Florida.

Lake Okeechobee Technical Advisory Council (LOTAC) II. 1990. Final Report to the Governor, State of Florida, Secretary, Department of Environmental Regulation, Governing Board, South Florida Water Management District, West Palm Beach, Florida. 64 pp.

Lean, David, Kenneth Reckhow, William Walker and Robert Wetzel. 1992. Everglades Nutrient Threshold Research Plan. Report to the Everglades Technical Oversight Committee. 10+ pp.

Limno-Tech, Inc. 1996. Data Analysis in support of the Everglades Forever Act. Final Report. Prepared for South Florida Water Management District.

Limno-Tech, Inc. 1996. Data Analysis in support of the Everglades Forever Act. Appendices. Prepared for South Florida Water Management District.

Lin, Steve, Ray Santee, Jorge Marban and Steve Reel. 1982. Water Quality Management Plan for the S-2 and S-3 Drainage Basins in the Everglades Agricultural Area. South Florida Water Management District Resource Planning Department. West Palm Beach, Florida. 69 pp. + Appendix

Loveless, Charles M. 1959. A study of the Vegetation in the Florida Everglades. Ecology 40:1-9.

Lutz, John. 1977. Water Quality Characteristics of Several Southeast Florida Canals. South Florida12

Water Management District Technical Publication 77-4. West Palm Beach, Florida. 83 pp. + Appendix

Lutz, John R. 1977. Water Quality and Nutrient Loadings of the Major Inflows From the Everglades Agricultural Area to the Conservation Areas, Southeast Florida. South Florida Water Management District Technical Publication 77-6. West Palm Beach, Florida. 40 pp. + Appendix

Maltby, E. 1985. Effects of Nutrient Loading on Decomposition Profiles in the Water Column and Submerged peat in the Everglades. pp. 450-464 in "Tropical Peat Resources- Prospects and Potential". Proceedings of the International Peat Society Symposium held in Kingston, Jamaica, February 25 - March 1, 1985. Helsinki University Press, Helsinki, Finland.

Madden, Marguerite, David Jones and Les Vilchek. Photointerpretation Key for the Everglades Vegetation Classification System. Photogrammetric Engineering and Remote Sensing 65(2):171-177.

Mattraw, Harold C., Daniel J. Scheidt, and Anthony C. Federico. 1987. Analysis of Trends in WaterQuality Data for Water Conservation Area 3A, the Everglades, Florida. U.S. Geological Survey, WaterResources Investigations Report 87-4142. USGS, Tallahassee, Florida. 52 pp.

McCormick, Paul, Fred Sklar, Jim Grimshaw, Sue Newman, Shili Miao, Pete Rawlick, and Tom Fontaine. 1994. Field mesocosm dosing studies to support derivation of numerical criteria for phosphorus in the Everglades. A revised work plan, July 26, 1994. South Florida Water Management District Everglades Systems Research Division. West Palm Beach, Florida. 34 pp.

McCormick, Paul V., Peter S. Rawlick, Kathy Lurding, Eric P. Smith, and Fred H. Sklar. 1996. Periphyton-water quality relationships along a nutrient gradient in the northern Florida Everglades. J. N.

Am. Benthol. Soc .15(4):43-449.

McCormick, Paul V. and Mary B. O’Dell. 1996. Quantifying Periphyton Responses to Phosphorus in the Florida Everglades: a Synoptic-Experimental Approach. J. N. Am. Benthol. Soc . 15(4):450-468

McCormick, Paul V. and John Cairns, Jr. 1997. Algal indicators of aquatic ecosystem condition and change. Chapter Seven, pp. 177-207 in “Plants for Environmental Studies”, W. Wang, J. Gorsuch and J. Hughes, editors. CRC Press, Inc. Boca Raton.

McCormick, Paul V., Michael J. Chimney and David R. Swift. 1997. Diel Oxygen Profiles and Water Column Community Metabolism in the Florida Everglades, U. S. A. Arch. Hydrobiol . 140(1):117-129.

McCormick, Paul V. and Leonard J. Scinto. 1998. Influence of Phosphorus loading on wetland periphyton assemblages. In “Phosphorus Biogeochemistry in Florida Ecosystems”. South Florida Water Management District Department of Research Publication 321. West Palm Beach, Florida .

McCormick, Paul V. and R. Jan Stevenson. 1998. Periphyton as a Tool for Ecological Assessment and Management in the Florida Everglades: Mini-review. J. Phycol . (34):726-733.

McCormick, Paul, Robert Shuford III, John Backus and William Kennedy. 1998a. Spatial and seasonal patterns of periphyton biomass and productivity in the northern Everglades, Florida, U. S. A. Hydrobiologia 362:185-208.

McCormick, Paul, Susan Newman, Shili Miao, Ramesh Reddy, Dale Gawlick, Carl Fitz, Tom Fontaine and13

Darlene Marley. 1998b. Ecological needs of the Everglades. September 9, 1998 Review Draft. Chapter 3 for the Everglades Forever Act Report to the Florida Legislature. South Florida Water Management District. West Palm Beach, Florida. 63 pp.

McCormick, Paul, Susan Newman, Shili Miao, Ramesh Reddy, Dale Gawlick, Carl Fitz, Tom Fontaine and Darlene Marley. 1999. Ecological needs of the Everglades. Chapter 3 in “Everglades Interim Report”. South Florida Water Management District. West Palm Beach, Florida. 66 pp.

McPherson, Benjamin F. 1970. Hydrobiological characteristics of Shark River Estuary, Everglades National Park, Florida. USGS Open File Report 71002. Tallahassee, Florida. 113 pp.

McPherson, Benjamin F. 1971. Water quality at the Dade-Collier Training and Transition Airport, Miami International Airport and Cottonmouth Camp, Everglades National Park, Florida, November 1969. USGS Open File Report 70011. Tallahassee, Florida. 29 pp.

McPherson, B. F. 1973. Vegetation in relation to water depth in Conservation Area 3, Florida. USGS Open File Report 73025. Tallahassee, Florida. 62 pp.

McPherson, B. F. 1973. Water Quality in the Conservation Areas of the central and Southern Flood Control District, 1970-72. USGS Open File Report 73014. Tallahassee, Florida. 39 pp.

McPherson, B. F., B. G. Waller, and H. C. Mattraw, Jr. 1976. Nitrogen and phosphorus uptake in the Everglades Conservation Areas with special reference to the effects of backpumping. USGS WRI 76-29. Tallahassee, Florida. 120 pp.

McPherson, B. F. and R. Halley. 1996. The South Florida Environment: A Region Under Stress. National Water Quality Assessment Program. U. S. Geological Survey Circular 1134. Denver, Colorado. 61 pp.

Miao, Shili, Fred Sklar, Bob Johnson, Sue Newman, Paul McCormick and Thomas Fontaine. 1996. Macrophyte field monitoring and experiments to support numerical interpretation of no-imbalance water quality criteria for the Everglades: A macrophyte threshold research plan. June 11, 1996. South Florida Water Management District Everglades Systems Research Division. West Palm Beach, Florida. 31 pp.

Miao, S.L., R.E. Borer and F. H. Sklar. 1997. Sawgrass Seedling Responses to Transplanting and

Nutrient Additions. Restoration Ecology , Vol. 5, No. 2, pp. 162-168.

Miao, S. L. and F. H. Sklar. 1998. Biomass and nutrient allocation of sawgrass and cattail along a nutrient gradient in Florida Everglades. Journal of Wetland Ecology and Management 5:245-263.

Miao, S. L., L. Kong, B. Lorenzens and R. R. Johnson. 1998. Versatile modes of propagation in Cladium jamaicense in the Florida Everglades. Annals of Botany 82:285-290

Miao, S. L., H. Stewart, M. Colbert and C. E. Carraher, Jr. In press. Relative effect of seed source, nutrients and hydroperiod on the germination of Cladium jamaicense in the Florida Everglades. South Florida Water Management District Department of Research Florida. Publication 308. West Palm Beach

Miao, S. L., P. V. McCormick, S. Newman and S. Rajagopalan. Submitted. Interactive effects of seed availability, water depths and phosphorus enrichment on cattail colonization in the Florida Everglades.14

Restoration Ecology.

Miao, S. L. and W. F. DeBusk. In press. Effects of phosphorus enrichment on the structure and function of sawgrass and cattail communities in the Everglades. In press. In Phosphorus biogeochemistry in Florida Ecosystems. K. R. Reddy, editor.

Millar, Paul S. 1981. Water Quality Analysis in the Water Conservation Areas 1978-79. South Florida Water Management District Technical Memorandum. West Palm Beach, Florida. 83 pp.

Millar, Paul S. 1981. Nutrient budgets of the Water Conservation Areas of South Florida, 1978-1980. pp. 187-208 in “Progress in wetlands utilization and management”, P. McCafferty, T. Beemer and S. Gatewood, editors. Coordinating Council on the Restoration of the Kissimmee River Valley and Taylor Creek-Nubbin Slough Basin. Tallahassee, Florida.

Miller, W. L. 1975. Nutrient concentrations of surface water in southern Florida September 1970 to April 1975. USGS Open File Report 75010. Tallahassee, Florida. 44 pp.

Miller, Wesley L. 1988. Description and Evaluation of the Effects of Urban and Agricultural Development on the Surficial Aquifer System, Palm Beach County, Florida. USGS WRI Report 88-4056. Tallahassee, Florida. 58 pp.

Moustafa, M. Z. 1996. Wetlands Nutrient Removal Design. South Florida Water Management District Department of Research Publication 243. West Palm Beach, Florida. 17 pp.

Moustafa, M. Z. 1997. Long-term Equilibrium Phosphorus Concentrations in the Everglades as predicted by a Vollenweider-type Model. Journal of the American Water Resources Association 34(1):135-147.

Moustafa, Mohamed Z. 1997. Graphical representation of Nutrient Removal in Constructed Wetlands.

Wetlands 17(4):493-501.

Moustafa, M., S. Newman, T. Fontaine, M. Chimney and T. Kosier. In press. Phosphorus retention by the Everglades Nutrient Removal Project: An Everglades Stormwater Treatment Area. SFWMD Department of Research Publication 278. West Palm Beach, Florida.

Nealson, D. 1984. Groundwater Quality Study of the Water Conservation Areas. South Florida Water Management District Technical Memorandum. West Palm Beach, Florida. 26 pp.

Nearhoof, Frank L. 1992. Nutrient-Induced Impacts and Water Quality Violations in the Florida Everglades. September 1992 Draft. Florida Department of Environmental Regulation Water Quality Technical Series, Vol. 3, Num. 24. Florida Department of Environmental Regulation, Tallahassee, Florida.

Newman., S., J. B. Grace, and J. W. Koebel. 1996. Effects of nutrients and hydroperiod on Typha,

Cladium and Eleocharis: Implications for Everglades Restoration. Ecological Applications 6(3):774-783.

Newman, S., K. R. Reddy, W. F. DeBusk, Y. Wang, G. Shih, and M. M. Fisher. 1997. Spatial Distribution of Soil Nutrients in a Northern Everglades Marsh: Water Conservation Area 1. Soil Sci. Soc.

Am. J. 61:1275-1283.

Newman, S., J. Schuette, J. B. Grace, K. R. Rutchey, T.D. Fontaine, K. R. Reddy and M. Pietrucha. 1998. Factors Influencing Cattail Abundance in the Northern Everglades. Aquatic Botany (60):265-280.15

Newman, Susan, Paul McCormick and John Backus. In press. Phosphatase activity as an early warning indicator of wetland eutrophication: problems and prospects. In . “Phosphatases in the environment”, B. A. Whitten, editor. Kluwer Academic Publishers.

Newman, S. and J. S. Robinson. In press. Forms of Organic Phosphorus in water, soils and sediments. In Phosphorus biogeochemistry in Florida Ecosystems. K. R. Reddy, editor.

Obeysekera, J. and K. Rutchey. 1997. Selection of Scale for Everglades landscape models. Landscape Ecology 12(1):7-18.

Olmsted, Ingrid, Lloyd Loope and Richard Rintz. 1980. A Survey and baseline analysis of aspects of the Vegetation of Taylor Slough, Everglades National Park. Everglades National Park South Florida Research Center Publication T-586. Homestead, Florida. 71 pp.

Olmsted, Ingrid and Lloyd Loope. 1984. Plant Communities of Everglades National Park. pp.167-184. in “Environments of South Florida: Present and Past II“ Miami Geological Society, Coral Gables, Florida. 551 pp.

Orem, William, Harry Lerch and Peter Rawlick. 1997. Geochemistry of Surface and Pore water at USGS Coring Sites in Wetlands of South Florida. United States Geological Survey Open File Report 97-454. 55

pp.

Ornes, W. Harold and Kerry K. Steward. 1973. Effect of phosphorus and potassium on phytoplankton populations in field enclosures. South Florida Environmental Project: Ecological Report No. DI-SFEP-74- 07. U. S. Department of Interior.

Pan, Yangdong, R. Jan Stevenson, Panchabi Vaithiyanathan, Jennifer Slate and Curtis Richardson. 1997. Using Experimental and Observational Approaches to determine causes of algal changes in the Everglades. Chapter 2 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J.

Zahina. 1997. Duke Wetland Center Publication 97-05.

Pomeroy, Lawrence, Robert Twilley and Dennis Whigham. 1995. External panel report: nutrient threshold research workshop. Report to South Florida Water Management District and the Everglades technical Oversight Committee. 13 pp.

Pope, K. R., J. R. Richardson, and W. E. Kitchens. 1987. Vegetation patterns in a northern Everglades Marsh. Paper presented at the eighth annual meeting of the Society of Wetland Scientists, Seattle, Washington, May 26-29, 1987. 5 pp.

Pope, Kevin R. 1989. Vegetation in relation to water quality and hydroperiod on the Loxahatchee National Wildlife Refuge. Master of Science Thesis. University of Florida. 79 pp.

Porter, P. S., and C. A. Sanchez. 1992. The Effect of Soil Properties on Phosphorus Sorption by Everglades Histosols. Soil Science 154:387-398.

Porter, P. S., and C. A. Sanchez. 1994. Nitrogen in the organic soils of the EAA. pp. 42-61 in “Everglades Agricultural Area: Water, Soil, Crop and Environmental Management”. University Press of Florida. Gainesville, Florida. 322 pp.16

Qian, Song and Curtis J. Richardson. 1997. Estimating the long-term phosphorus accretion rate in the Everglades: A Bayesian approach with risk assessment. Water Resources Research 33(7):1681-1688

Qualls, Robert G. and Curtis Richardson. 1995. Forms of Phosphorus along a nutrient enrichment gradient in the northern Everglades. Soil Science 160(3):183-198.

Radar, Russell B. 1994. Macroinvertebrates of the Northern Everglades: Species Composition and Trophic Structure. Florida Scientist 57 (1,2):22-33.

Rader, Russell B., and Curtis J. Richardson. 1992. The Effects of Nutrient Enrichment on Algae and Macroinvertebrates in the Everglades: A Review. Wetlands 12:121-135.

Rader, R. B., and C. J. Richardson. 1994. Response of Macroinvertebrates and Small Fish to Nutrient Enrichment in the Northern Everglades. Wetlands 14:134-146.

Raschke, R. L. 1992. The response of microcoleus lyngbaceus (Kutz .) crouan to phosphorus enrichment in the oligotrophic Everglades National Park, Florida. USEPA Region 4, Athens, Georgia. 14 pp.

Raschke, R. L. 1993. Diatom (Bacillariophyta) Community Response to Phosphorus in the Everglades National Park, USA. Phycologia 32:48-58.

Reckhow, Kenneth and Song Qian. 1994. Modeling phosphorus trapping in wetlands using generalized

additive models. Water Resources Research 30(11):3105-3114.

Reddy, K. R., and W. F. DeBusk. 1985. Nutrient Removal Potential of Selected Aquatic Macrophytes. Journal of Environmental Quality 14:459-462.

Reddy, K. R., W. F. DeBusk, Y. Wang, R. DeLaune, and M. Koch. 1991a. Physico-Chemical Properties of Soils in the Water Conservation Area 2 of the Everglades. Final Report. Submitted to South Florida Water Management District. Submitted by the Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida.

Reddy, K. R., Y. Wang, L. Scinto, M. M. Fisher, and M. Koch. 1991b. Physico-Chemical Properties of Soils in the Holeyland Wildlife Management Area. Final Report. Submitted to South Florida Water Management District. Submitted by the Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida.

Reddy, K. R., and D. A. Graetz. 1991. Phosphorus Dynamics in the Everglades Nutrient Removal System (Knight's Farm). Annual Report to the South Florida Water Management District. Submitted by the Soil Science Department, University of Florida, Gainesville, Florida.

Reddy, K. R., R. D. DeLuane, W. F. DeBusk, and M. S. Koch. 1993. Long-Term Nutrient Accumulation Rates in the Everglades. Soil Sci. Soc. Am. J. 57:1147-1155.

Reddy, K. R., Y. Wang, W. F. DeBusk, and S. Newman. 1994. Physico-Chemical Properties of Soils in the Water Conservation Area 3 of the Everglades. Final Report. Submitted to South Florida Water Management District. Submitted by the Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida. 68 pp. plus appendices.

Reddy, K. R., Y. Wang, W. F. DeBusk, M. M. Fisher and S. Newman. 1998. Forms of Soil Phosphorus in17

selected hydrologic units of the Florida Everglades. Soil Sci. Soc. Am J. 62:1134-1147.

Redfield, Garth W. 1998. Quantifying Atmospheric Deposition of Phosphorus: A Conceptual Model and Literature Review for Environmental Management. South Florida Water Management District Technical Publication #360. West Palm Beach, Florida. 35 pp.

Reeder, Pamela B. and Steven M. Davis. 1983. Decomposition, Nutrient Uptake and Microbial Colonization of Sawgrass and Cattail Leaves in Water Conservation Area 2A. South Florida Water Management District Technical Publication 83-4. West Palm Beach, Florida. 24 pp.

Richardson, C. and C. Craft. 1990. Phase One: Preliminary Assessment of Nitrogen and Phosphorus Accumulation and Surface Water Quality in Water Conservation areas 2A and 3A of Southern Florida. Submitted to the Florida Sugar Cane League. Duke Wetland Center Publication 90-01. 148 pp.

Richardson, C., C. Craft, R. Qualls, R. Radar, and R. Johnson. 1991. Annual report: Effects of Nutrient Loadings and Hydroperiod alterations on cattail expansion, community structure and nutrient retention in the Water Conservation Areas of South Florida. Submitted to the Agricultural Area Environmental Protection District. Duke Wetland Center Publication 91-08. 318 pp.

Richardson, C., C. Craft, R. Qualls, R. Radar, and R. Johnson. 1991. Annual report appendices: Effects of Nutrient Loadings and Hydroperiod alterations on cattail expansion, community structure and nutrient retention in the Water Conservation Areas of South Florida. Submitted to the Agricultural Area Environmental Protection District. Duke Wetland Center Publication 91-09 92 pp.

Richardson, Curtis J., C. Craft, R. Johnson, R. Qualls, R. Rader, L. Sutter and J. Vymazal. 1992. Effects of Nutrient Loadings and Hydroperiod Alterations on Control of Cattail Expansion, Community Structure and Nutrient Retention in the Water Conservation Areas of South Florida. Annual Report. Duke Wetland Center Publication 92-11. 439 pp.

Richardson, C. J. and C. B. Craft. 1993. Effective Phosphorus Retention in Wetlands: Fact or Fiction. pp.

271-282 in

"Constructed Wetlands for Water Quality Improvement", edited by Gerald A. Moshiri. Lewis Publishers, Ann Arbor, Michigan.

Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, S. Bartow, C. Chiang, R. Johnson, and J. Zahina. 1994. Effects of Nutrient Loadings and Hydroperiod Alterations on Control of Cattail Expansion, Community Structure and Nutrient Retention in the Water Conservation Areas of South Florida. Annual Report. Duke Wetland Center Publication 94-08. 368 pp.

Richardson, C. J and P. Vaithiyanathan. 1995. Phosphorus Sorption Characteristics of Everglades Soils along a Eutrophication Gradient. Soil Sci. Soc. Am. J . 59:1782-1788.

Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1995. Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades. 1995 Annual Report to the Everglades Agricultural Area Environmental Protection District. Duke Wetland Center Publication 95-05. 372 pp.

Richardson, Curtis, Panchabi Vaithiyanathan, Edwin Romanowicz and Christopher Craft. 1997a. Macrophyte Community responses in the Everglades with an emphasis on Cattail (Typha domingensis) and sawgrass (Cladium Jamaicense) interactions along a gradient of long-term nutrient additions, altered hydroperiod and fire. Chapter 14 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem18

Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997. Duke Wetland Center Publication 97-05.

Richardson, Curtis, Panchabi Vaithiyanathan, Jerry Qualls and Craig Stowe. 1997b. Dosing Study Chemistry analysis: Four-year response (1992-1996) of Everglades Sloughs to increased concentrations of

PO 4: Operation of experimental field mesocosms and water quality analysis. Chapter 15 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997. Duke Wetland

Center Publication 97-05.

Richardson, Curtis, Robert Qualls and Panchabi Vaithiyanathan. 1997c. Dosing study- changes in macrophyte community composition and calcareous mat cover over four years of P additions to Everglades mesocosms. Chapter 17 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush

and J. Zahina. 1997. Duke Wetland Center Publication 97-05.

Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997d. Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades. 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Duke Wetland

Center Publication 97-05.

Richardson, John R., Wade L. Bryant, Wiley M. Kitchens, Jennifer E. Mattson and Kevin R. Pope. 1990. An evaluation of habitats and relationships to water quality, quantity and hydroperiod: A synthesis report. Prepared for Loxahatchee National Wildlife Refuge. Florida Cooperative Fish and Wildlife Research Unit, Gainesville, Florida. 166 pp.

Rose, Paul W. and Peter C. Rosendahl. 1979. An application of LANDSAT multispectral imagery for the classification of hydrobiological systems, Shark River Slough, Everglades National Park, Florida. Everglades National Park South Florida Research Center Publication T-544. Homestead, Florida. 65 pp.

Rose, Paul W. and Peter C. Rosendahl. 1983. Classification of Landsat data for hydrologic application, Everglades National Park. Photogrammetric Engineering and Remote Sensing 49(4):505-511.

Rosendahl, Peter C. and Paul W. Rose. 1979. Water Quality Standards: Everglades National Park. Environmental Management , Vol. 3, No. 6, pp. 483-491.

Rudnick, D., Z. Chen, D. Childers, J. Boyer and T. Fontaine. In press. Phosphorus and nitrogen inputs into Florida Bay: the importance of the Everglades watershed. In: “Phosphorus biogeochemistry of sub-tropical ecosystems: Florida as a case study”. K. R. Eddy, G. A. O’Conner, and C. L. Schelske, editors. CRC/Lewis publishers. South Florida Water Management District Department of Research Publication 310. West Palm Beach, Florida

Rutchey, Ken and Les Vilchek. 1994. Development of an Everglades Vegetation Map using a SPOT image and the Global Positioning System. Photogrammatic Engineering and Remote Sensing 60(6):767-775.

Rutchey, Ken and Les Vilchek. 1999. Air Photointerpretation and Satellite Imagery Analysis Techniques19

for Mapping Cattail Coverage in a Northern Everglades Impoundment. Photogrammetric Engineering and Remote Sensing 65(2):185-191.

Sanchez, C. A., P. S. Porter, and M. F. Ulloa. 1991. Relative efficiency of broadcast and banded phosphorus for sweet corn produced on histosols. Soil Sci. Soc. Am. J. 55:871-875.

Sanchez, Charles A. and P. Steven Porter. 1994. Phosphorus in the Organic Soils of the EAA. pp. 62-84 in “Everglades Agricultural Area: Water, Soil, Crop and Environmental Management”. University Press of Florida. Gainesville, Florida. 322 pp.

Scheidt, Daniel J., David R. Walker, Ramona G. Rice and Mark D. Flora. 1985. Diel Dissolved Oxygen Levels under Experimental Nutrient Loading Conditions in Shark Slough, Everglades National Park,

Florida. Abstract. Florida Scientist Volume 48 Supplement 1:36.

Scheidt, Daniel J. 1988. Nutrient Enrichment in the Everglades. National Wetlands Newsletter 10:5-7.

Scheidt, D.J., M.D. Flora, and D. R. Walker. 1989. Water Quality Management for Everglades National Park. P. 377-390. In: “Wetlands: Concerns and Success”. American Water Resources Association, Bethesda, MD. USA.

Science Sub-group. 1997. Ecologic and precursor success criteria for South Florida Ecosystem restoration. Report to the Working Group of the South Florida Ecosystem Restoration Task Force. Compiled and printed by Planning Division, USACE, Jacksonville, Florida. May 1997.

Scinto, L. J. 1997. Phosphorus cycling in a periphyton-dominated freshwater wetland. Ph. D. Thesis. University of Florida. Gainesville, Florida. 195 pp.

Shahane, A., D. Paich and R. L. Hambrick. 1977. A Framework of the Water Quality planning model for the Conservation Areas of the Florida Everglades. South Florida Water Management District Report. West Palm Beach, Florida.

Shahane, A. and John R. Maloy. 1978. The Water Quality Planning Model. South Florida Water Management District. West Palm Beach, Florida

Slate, J. E. 1998. Inferring present and historical environmental conditions in the Everglades with diatoms. PhD. Thesis. University of Louisville. Louisville, Kentucky. 110 pp.

Smith, Eric P. 1994. Statistical Analysis of cattail changes in the Holeyland. A report to the South Florida Water Management District. 14 pp. plus tables, appendices.

Smith, Eric P. and Paul V. McCormick. In press. Long-term relationships between phosphorus inputs and wetland phosphorus concentrations in a northern Everglades marsh. 28 pp. plus figures.

Snyder, G. H. and J. M. Davidson. 1994. Everglades Agriculture: Past, Present and Future. pp. 85-115 in "Everglades: The Ecosystem and its Restoration." S. M. Davis and J. C. Ogden, (eds). St. Lucie Press, Delray Beach, Florida.

Sonntag, Wayne H. 1987. Chemical characteristics of Water in the Surficial Aquifer System, Dade20

County, Florida. USGS WRI Report 87-4080. Tallahassee, Florida. 42 pp.

South Florida Water Management District. 1977. Water Use and Supply Development Plan. Volume IIIA. Lower East Coast Planning Area Technical Exhibits A - H. South Florida Water Management District. West Palm Beach, Florida.

South Florida Water Management District. 1978. Overview of Cooperative Water Quality Studies in the Everglades Agricultural Area. South Florida Water Management District Water Chemistry Division and the Florida Sugar Cane League. West Palm Beach, Florida. 49 pp.

South Florida Water Management District. 1982. An Analysis of Water Supply Backpumping for the Lower East Coast Planning Area. Special Report. West Palm Beach, Florida. 107 pp.

South Florida Water Management District. 1984. North New River Backpumping Water Quality Impact Study Report #1 Preconstruction and initial Operation. Technical Memorandum. West Palm Beach, Florida. 47 pp.

South Florida Water Management District. 1985. Water quality evaluation of Everglades Agricultural Area Interim Action Plan. Draft. Chemistry Division, Planning Department, July 20, 1985. 13 pp. plus tables and figures.

South Florida Water Management District. 1992. Surface Water Improvement and Management Plan for the Everglades. Supporting Information Document. March 12, 1992. South Florida Water Management District, West Palm Beach, Florida. 472 pp.

South Florida Water Management District. 1994. Research Implementation Plan: Everglades ecosystem processes (EEP): analyses to determine the biogeochemical and hydrologic parameters that cause large-scale ecological change. February 3, 1994. South Florida Water Management District Everglades Systems Research Division, West Palm Beach, Florida. 16 pp. plus attachments.

South Florida Water Management District. 1995. Everglades Best Management Practice Program. Water year 1995. South Florida Water Management District, West Palm Beach, Florida.

South Florida Water Management District. 1996. Evaluation of benefits and impacts of the hydropattern restoration components of the Everglades Construction Project. September 13, 1996. South Florida Water Management District, West Palm Beach, Florida. 88 p. plus appendix.

South Florida Water Management District. 1997. Everglades Best Management Practice Program. Water year 1996 and water year 1997. South Florida Water Management District, West Palm Beach, Florida. 122

pp.

South Florida Water Management District. 1997. Everglades Best Management Practice Program. Water year 1997. Updated data. South Florida Water Management District, West Palm Beach, Florida. 50 pp.

South Florida Water Management District. 1997. Atmospheric Deposition into South Florida. Advisory panel final report. December 24, 1997. South Florida Water Management District, West Palm Beach, Florida. 37 pp.

South Florida Water Management District. 1998. Everglades Nutrient Removal Project 1997 Annual21

Monitoring Report. South Florida Water Management District. West Palm Beach, Florida.

South Florida Water Management District. 1998. Everglades Best Management Practice Program. Water year 1998. South Florida Water Management District, West Palm Beach, Florida. 83 pp.

South Florida Water Management District. 1999. Everglades Interim Report. West Palm Beach, Florida.

Spalding, M. G., G. T. Bancroft and D. Forrester. 1993. The Epizootiology of Eustrongylidosis in wading birds (Ciconiformes) in Florida. Journal of Wildlife Diseases 29(2):237-249.

Spalding, M. G. and D. Forrester. 1993. Pathogenesis of Eustrongylides Ignotus (Nemotoda: Dioctophymatoidea) in Ciconiformes. Journal of Wildlife Diseases 29(2):250-260.

Spalding, M. G. and D. J. Forrester. 1991. Effects of Parasitism and Disease on the Nesting Success of Colonial Wading Birds (Ciconiiformes) in Southern Florida. Florida Game and Fresh Water Fish Commission Nongame Wildlife Program Final Report NG88-008.

Steiglitz, W. O. 1964. A status report on the vegetation of the Loxahatchee Refuge Pool (Conservation Area 1). USFWS memorandum. 12 pp.

Steward, Kerry K. 1984. Physiological, edaphic and environmental characteristics of Everglades Sawgrass Communities. Pp. 157-166 in “Environments of South Florida: Present and Past II” Miami Geological Society, Coral Gables, Florida. 551 pp.

. Steward, Kerry and W. H. Ornes. 1973. Investigations into the mineral nutrition of sawgrass using experimental culture techniques. South Florida Environmental Project: Ecological Report No. DI-SFEP-74- 05. U. S. Department of Interior. 22 pp.

Steward, K. K. 1973. Inorganic nutrient utilization by aquatic vegetation of the Florida Everglades. Report to U. S. Department of Interior. NTIS Number PB-231608, 231609.

Steward, Kerry K., and W. Harold Ornes. 1975a. Assessing a Marsh Environment for Wastewater

Renovation. Journal Water Pollution Control Federation 47:1880-1891.

Steward, Kerry K., and W. Harold Ornes. 1975b. The Autecology of Sawgrass in the Florida Everglades. Ecology 56:162-171.

Steward, Kerry K., and W. H. Ornes. 1983. Mineral Nutrition of Sawgrass ( Cladium Jamaicense Crantz) in Relation to Nutrient Supply. Aquatic Botany 16:349-359.

Stewart, Herbert, Shi Li Miao, Marsha Colbert, and Charles E. Carraaher, Jr. 1997. Seed Germination of two cattail ( Typha) species as a function of Everglades Nutrient Levels. Wetlands 17(1):116-122.

Stober, Q. J., R. D. Jones and D. J. Scheidt. 1995. Ultra-trace level mercury in the Everglades Ecosystem: A Multi-media Pilot Study. Water, Air and Soil Pollution 80:991-1001.

Stober, Jerry, Daniel Scheidt, Ron Jones, Kent Thornton, Robert Ambrose, and Danny France. 1996. South Florida Ecosystem Assessment. Monitoring for Adaptive Management: Implications for Ecosystem Restoration. Interim Report. United States Environmental Protection Agency EPA-904-R-96-008. 26+ pp.22

Stober, Jerry, Daniel Scheidt, Ron Jones, Kent Thornton, Robert Ambrose, and Danny France. 1998. South Florida Ecosystem Assessment. Monitoring for Adaptive Management: Implications for Ecosystem Restoration. Final Technical Report - Phase I. United States Environmental Protection Agency EPA-904-

R-96-008.

Stone, J. A., and D. E. Legg. 1992. Agriculture and the Everglades. pp 207-215 in Journal of Soil and

Water Conservation May-June, 1992.

Swift, David R. 1981. Preliminary Investigations of Periphyton and Water Quality Relationships in the Everglades Water Conservation Areas. South Florida Water Management District Technical Publication 81-5. West Palm Beach, Florida. 83 pp. + Appendices

Swift, David R.1984. Periphyton and water quality relationships in the Everglades Water Conservation Areas. Pp. 97-117 in “Environments of South Florida: Present and Past II“ Miami Geological Society, Coral Gables, Florida. 551 pp.

Swift, David R. 1986. Baseline Water Quality Conditions and Periphyton Community Structure in WCA3B July 1982 - November 1983. Draft Technical Publication. South Florida Water Management District Environmental Sciences Division. 54 pp.

Swift, David and Brent Nicholas. 1983. Preliminary Transect Study of the Effects of C-123 and C-60 Canal Water Discharges Across the WCA-3A Marsh. South Florida Water Management District Technical Memorandum to the Files. West Palm Beach, Florida.

Swift, David and Robert B. Nicholas. 1987. Periphyton and Water Quality Relationships in the Everglades Water Conservation Areas 1978-1982. South Florida Water Management District Technical Publication 87-2. West Palm Beach, Florida. 44 pp. + appendices.

Tate, Robert L. III. 1977. Nitrification in histosols: a potential role for the heterotrophic nitrifer. Applied and Environmental Microbiology 33(4):911-914.

Tate, Robert L. III. 1979. Microbial activity in organic soils as affected by soil depth and crop. Applied and Environmental Microbiology 37(6):1085-1090.

Tate, Robert, III. 1980. Effect of several environmental parameters on carbon metabolism in histosols. Microbial Ecology 5:329-336.

Tate, Robert, III. 1980. Variation in heterotrophic and autotrophic nitrifer populations in relation to nitrification in organic soils. Applied and Environmental Microbiology 40(1):75-79.

Tate, Robert L. III and Richard Terry. 1980. Effect of sewage effluent on microbial activities and coliform populations of Pahokee muck. Journal of Environmental Quality 9(4): 673-677.

Terry, Richard E. 1980. Nitrogen Mineralization in Florida Histosols. Soil Sci. Soc. Am. J. 44:747-750.

Terry, Richard and Robert Tate, III. 1980. Denitrification as a pathway for nitrate removal from organic

soils. Soil Science 129(3):162-166

Terry, Richard and Robert Tate, III. 1080. The effect of nitrous oxide reduction in organic soils and

sediments. Soil Sci. Soc. Am. J. 44(4):744-746.23

Terry, Richard E. and Robert Tate, III. 1981. Municipal wastewater re-utilization on cultivated soil.

Journal WPCF

53(1):85-88.

Terry, Richard, Robert Tate III, and John Duxbury. 1981. Nitrous oxide emissions from drained, cultivated organic soils of South Florida. Air Pollution Control Association Journal 31(11):1173-1176

Terry, Richard, Robert Tate III, and John Duxbury. 1981. The effect of flooding on nitrous oxide emissions from an organic soil. Soil Science 132(3):228-232.

Toth, Louis A. 1987. Effects of hydrologic regimes on lifetime production and nutrient dynamics of sawgrass. South Florida Water Management District Technical Publication 87-6. West Palm Beach, Florida. 32 pp.

Toth, Louis A. 1988. Effects of hydrologic regimes on lifetime production and nutrient dynamics of cattail. South Florida Water Management District Technical Publication 88-6. West Palm Beach, Florida. 26 pp.

Turner, R. E., E. M. Swenson, N. N. Rabalais and L. E. Smith. 1998. Regional Environmental Monitoring and Assessment Program: Florida Everglades Ecosystem. Final report to U. S. Environmental Protection Agency Office of Research and Development, Environmental Research Laboratory, Gulf Breeze, Florida. Louisiana State University Coastal Ecology Institute. Baton Rouge, Louisiana. 213 p.

Turner, Andrew M., Joel C. Trexler, C. Frank Jordan, Sarah J. Slack, Pamela Geddes, John Chick and William F. Loftus. In press. Targeting ecosystem features for conservation: standing crops in the Florida Everglades. Conservation Biology

.

U. S. Department of the Interior. 1971. Appraisal of Water Quality Needs and Criteria for Everglades National Park. USDI National Park Service, Washington, D. C. June 1971. 50 pp.

U. S. District Court, Southern District of Florida. 1992. Consent Decree. Settlement Agreement July, 11, 1991. United States of America versus the South Florida Water Management District and the Florida Department of Environmental Regulation. Case Number 88-1886-CIV-Hoevelor. Miami, Florida..

Urban, Nancy H. and Joseph W. Koebel, Jr. 1993. Macroinvertebrate Colonization on Decomposing Sawgrass ( Cladium jamaicense Crantz.) and Cattail ( Typha domingensis Pers.) Litter in the Florida Everglades. Department of Research Report 118, South Florida Water Management District, West Palm Beach, FL. 38 pp.

Urban, N. H., S. M. Davis, and N. G. Aumen. 1993. Fluctuations in Sawgrass and Cattail Densities in Everglades Water Conservation Area 2A Under Varying Nutrient, Hydrologic and Fire Regimes. Aquatic Botany 46:203-223.

Vaithiyanathan, Panchabi, Curtis Richardson, Jan Vymazal and John Zahina. 1997a. Biogeochemical characteristics of the Everglades Sloughs. Chapter 5 in “Effects of Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997b. Duke Wetland Center Publication 97-05.

Vaithiyanathan, Panchabi, John Zahina, Sherri Cooper, and Curtis Richardson. 1997b. Examination of the seed bank along a eutrophication gradient in the northern Everglades. Chapter 10 in “Effects of24

Phosphorus and Hydroperiod Alterations on Ecosystem Structure and Function in the Everglades.” 1997 Annual Report to the Everglades Agricultural Area Environmental Protection District. Richardson, Curtis J., C. Craft, R. Qualls, J. Stevenson, P. Vaithiyanathan, M. Bush and J. Zahina. 1997. Duke Wetland

Center Publication 97-05.

Vaithiyanathan, P., C. Richardson, R. Kavanaugh, C. Craft and T. Barkay. 1996. Relationships of Eutrophication to the distribution of Mercury and to the Potential for Methylmercury Production in the Peat Soils of the Everglades. Envirn. Sci. Technol . (30):2591-2597.

Vaithiyanathan, P., and C. Richardson. 1997. Nutrient profiles in the Everglades: examination along the eutrophication gradient. Science of the Total Environment 205:81-95.

Vaithiyanathan, P., and C. Richardson. 1999. Biogeochemical characteristics of the Everglades Sloughs. J. Environ. Qual. 27:1439-1450.

van der Valk, Arnold, and Thomas Rosburg. 1997. Seed bank composition along a Phosphorus Gradient in the Northern Florida Everglades. Wetlands 17(2):228-236.

Van Meter, Nancy. 1965. Some quantitative and qualitative aspects of periphyton in the Everglades. Master of Science Thesis. University of Miami. Miami, Florida. 108 pp.

Van Meter-Kasinof, N. 1973. Ecology of the micro-algae of the Florida Everglades. Part I. Environment and some aspects of freshwater periphyton, 1959-1963. Nova Hedwegia 24:619-664.

Vymazal, Jan, C. Craft and C. Richardson. 1994. Periphyton response to nitrogen and phosphorus additions in the Florida Everglades. Algological Studies 73:75-97.

Vymazal, Jan and Curtis J. Richardson. 1995. Species Composition, Biomass, and Nutrient Content of Periphyton in the Florida Everglades. J. Phycol. 31:343-354.

Wade, Dale, John Ewel, and Ronald Hofstetter. 1980. Fire in South Florida Ecosystems. U. S. Department of Agriculture Forest Service General Technical Report SE-17. Southeastern Forest Experiment Station, Asheville, North Carolina. 125 pp.

Walker, David R., Mark D. Flora, Ramona G. Rice, and Daniel J. Scheidt. 1988. The Response of the Everglades Marsh to Increased Nitrogen and Phosphorus Loading, Part II: Macrophyte Community Structure and Chemical Composition. Report to the Superintendent. Everglades National Park, Homestead, FL. 34 pp.

Walker, William W. 1989. Rainfall total phosphorus concentrations and loadings in Everglades National Park.. August 1989. W. Walker, Concord, Massachusetts. 18 pp.

Walker, W. 1990. Water Quality Trends at Inflows to Everglades National Park. September 1990. Prepared for U.S. Dept. Justice. Environmental and Natural Resources Division. Washington D.C.

Walker, W. W. 1991. Water Quality Trends at Inflows to Everglades National Park. Water Resources

Bulletin 27:59-72.

Walker, William W., Jr. 1993. A Mass-Balance Model for Estimating Phosphorus Settling Rate in Everglades Water Conservation Area-2A. Prepared for U. S. Department of Justice. 9 pp. Plus figures and25

tables.

Walker, William W., Jr. 1995. Design Basis for Everglades Stormwater Treatment Areas. Water

Resources Bulletin , 1995 31(4):671-685.

Walker, William W., Jr. 1996. Test for evaluating performance of Stormwater Treatment Areas. January 3, 1996 draft. Prepared for U. S. Department of Interior .

Walker, William W., Jr. 1997a. Long-term water Quality trends in the Everglades. Presented at “Symposium on Phosphorus Biogeochemistry in Florida Ecosystems”. Clearwater Beach, Florida July 13- 16,1997. 20 pp.

Walker, William W., Jr. 1997b. Analysis of water quality and hydrologic data from the C-111 Basin. October 3, 1997 draft. Prepared for U. S. Department of Interior. 20 pp plus figures and tables.

Walker, William W., Jr. 1997c. Water Quality Aspects of the Proposed East-Coast Buffer Strip: Evaluation of the C11-West Basin. Draft. Prepared for U.S. Department of the Interior, Everglades National Park. 22 pp + Tables & Figures.

Walker, William W., Jr. 1997d. Review of Procedures for Tracking Refuge P Levels and ENP Inflow P Limits. Prepared for U. S. Department of Interior, Everglades National Park. April 17, 1997. 43 pp.

Walker, William W., Jr. 1998. Everglades monitoring report. Prepared for U. S. Department of Interior. June 17, 1998. Concord, Massachusetts.

Walker, William W., Jr. and Robert H. Kadlec. 1996. A Model for Simulating Phosphorus Concentrations in Waters and Soils Downstream of Everglades Stormwater Treatment Areas. Draft. Prepared for U. S. Department of Interior. 109 pp.

Waller, Bradley and J. E. Earle. 1975. Chemical and Biological Quality of water in part of the Everglades, Southeastern Florida. USGS Water Resources Investigation 56-75. Tallahassee, Florida. 157 pp.

Waller, Bradley G. 1975. Distribution of Nitrogen and Phosphorus in the Conservation Areas in South Florida from July 1972 to July 1973. USGS Water Resources Investigation 5-75. Tallahassee, Florida. 33

pp.

Waller, Bradley G. 1976. Analysis of selected benthic communities in Florida Everglades with reference to their physical and chemical environments. USGS Water Resources Investigation 76-28. Tallahassee, Florida. 33 pp.

Waller, Bradley. 1978. Effects of Land use and Water Management on Water Quality in the Western South New River Canal Basin, Southeast Florida, 1974-75. USGS Water Resources Investigation 78-30. Tallahassee, Florida. 56 pp.

Waller, Bradley. 1981a. Effects of Land use on Surface Water Quality in the East Everglades, Dade County, Florida. USGS Water Resources Investigation 81-59. Tallahassee, Florida. 43 pp.

Waller, Bradley. 1981b. Water Quality data for selected stations in the East Everglades, Florida. USGS26

Open File Report 81-821. Tallahassee, Florida. 77 pp.

Waller, Bradley. 1982a. Water Quality Characteristics of Everglades National Park, 1959-1977, with reference to the effects of Water Management. USGS Water Resources Investigation 82-34. Tallahassee, Florida. 51 pp.

Waller, Bradley. 1982b. Effects of Land use on Groundwater Quality in the East Everglades, Dade County, Florida. USGS Water Resources Investigation 82-4093. Tallahassee, Florida. 67 pp.

Waller, Bradley. 1982c. Effects of Land use on Surface water Quality in the East Everglades, Dade County, Florida. USGS Water Resources Investigation 81-59. Tallahassee, Florida. 37 pp.

Welch, R., M. Remillard, and R. F. Doren. 1995. GIS Database Development for South Florida’s National

Parks and Preserves. Photogrammetric Engineering and Remote Sensing 61(11):1371-1381.

Welch, Roy, Marguerite, and Robert F. Doren. 1999. Mapping the Everglades. Photogrammetric Engineering and Remote Sensing 65(2):163-170.

Whalen, Benita, Tom Kosier, Dean Mades, and Jacqulyn Larson. 1998. Effectiveness of Best Management Practices. September 9, 1998 Review Draft. Chapter 5 in the Everglades Forever Act Report to the Florida Legislature. South Florida Water Management District. West Palm Beach, Florida. 15 pp.

Whalen, P. and B. Whalen. 1996. Nonpoint Source Best Management Practices Program for the Everglades Agricultural Area. Paper number 962071 presented at the 1996 ASAE Annual International Meeting, July 14-18, 1996, Phoenix, Arizona. 25 pp. South Florida Water Management District.

Wiggins, T. Scott and A. B. Bottcher. 1994. EAA Water Quality Research, Monitoring and Abatement Programs. pp. 154-193 in “Everglades Agricultural Area: Water, Soil, Crop and Environmental Management.” University Press of Florida. Gainesville, Florida. 322 pp.

Wilson, Susan Uhl. 1974. Metabolism and Biology of a Blue Green Algal Mat. Master of Science Thesis. University of Miami. Miami, Florida. 81 pp.

Wood, E. J. and H. G. Maynard. 1974. Ecology of micro-algae of the Florida Everglades. Pp. 123-145 in “Environments of South Florida: Present and Past” Miami Geological Society, Coral Gables, Florida.

Wood, John M. and George W. Tanner. 1990. Graminoid Community composition and structure within four Everglades Management Areas. Wetlands 10(2):127-149.

Worth, Dewey. 1983. Progress report: preliminary environmental responses to marsh dewatering and reduction in water regulation schedule in Water Conservation Area2A.. South Florida Water Management District Technical Publication 83-6. West Palm Beach, Florida. 63 pp. plus appendix.

Worth, Dewey A. 1988. Environmental response of WCA2A to reduction in regulation schedule and marsh drawdown. South Florida Water Management District Technical Publication 88-2. West Palm Beach, Florida. 55 pp.

Wu, Yegang, Fred Sklar, Kishore Gopu and Ken Rutchey. 1996. Fire simulations in the Everglades27

Landscape using parallel programming. Ecological modelling 93:113-124.

Wu, Yegang, Fred H. Sklar and Ken Rutchey. 1997. Analysis and Simulations of Fragmentation Patterns in the Everglades. Ecological Applications, 7(1), pp. 268-276.

Zaffke, Michael. 1983. Plant Communities of Water Conservation Area 3A; Base-Line Documentation Prior to the Operation of S-339 and S-340. South Florida Water Management District Technical Memorandum. West Palm Beach, Florida. 31 pp. + Appendix