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Project Work Plan

U.S. Geological Survey, Greater Everglades Priority Ecosystems Science (GE PES)

Fiscal Year 2007 Study Work Plan

Study Title: Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area
Study Start Date: 10/1/03 Study End Date: 9/30/08
Web Sites: http://sofia.usgs.gov/exchange/flaecohist/, http://sofia.usgs.gov/projects/eh_swcsrs/index.html
Location (Subregions, Counties, Park or Refuge): Everglades NP, Big Cypress Preserve, Ten Thousand Islands NWR. Monroe, Collier, and Lee Counties.
Funding Source: USGS Greater Everglades Priority Ecosystems Science (GE PES) Program
Other Complementary Funding Source(s):
None at this time
Funding History: FY04 ; FY05 ; FY06 , FY07
Principal Investigator(s): G. Lynn Wingard
Study Personnel:
T. Cronin, D. Willard, C. Holmes, W. Orem, M. Corum, T. Lerch, M. Marot, J. Murray, T. Sheehan - USGS. Contract personnel: R. Ortiz, C. Budet, K. Waylen, 1/2 time ECO for terrestrial cores. Potential cooperative work: G. Dwyer, Duke University; M. Savarese, Florida Gulf Coast University, P. Swart, University of Miami.
Supporting Organizations:
South Florida Water Management District, Everglades National Park, Big Cypress Preserve, Ten Thousand Islands NWR
Associated / Linked Studies:
Historical Changes in Salinity, Water Quality and Vegetation in Biscayne Bay (ended in FY06); Paleosalinity as a Key for Success Criteria in South Florida Restoration (ended FY05); Integrated Biogeochemical Studies in the Everglades; Synthesis of South Florida Ecosystem History Research

Overview & Objective(s): One of the primary goals of the Central Everglades Restoration Plan (CERP) is to restore the natural flow of water through the terrestrial Everglades and into the coastal zones. Historically, Shark River Slough, which flows through the central portion of the Everglades southwestward, was the primary flow path through the Everglades Ecosystem. However, this flow has been dramatically reduced over the last century as construction of canals, water conservation areas and the Tamiami Trail either retained or diverted flow from Shark River Slough. The reduction in flow and changes in water quality through Shark River have had a significant effect on the freshwater marshes and the associated coastal ecosystems. Additionally, the flow reduction may have shifted the balance of fresh to salt-water inflow along coastal zones, resulting in an acceleration of the rate of inland migration of mangroves into the freshwater marshes. The objectives of this study are to document impacts of changes in salinity, water quality, coastal plant and animal communities and other critical ecosystem parameters on a sub-decadal to centennial scale in the southwest coastal region (from Whitewater Bay, north to the Ten Thousand Islands), and to correlate these changes with natural events and resource management practices. Emphasis will be placed on 1) determining the amount, timing and sources of freshwater influx (groundwater vs. runoff) into the coastal ecosystem prior to and since significant anthropogenic alteration of flow; and 2) determining whether the rate of mangrove and brackish marsh migration inland has increased since 20th century water diversion and what role sea level rise might play in the migration.

Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)

One of the primary DOI activities discussed in the DOI Science Plan is to "ensure that hydrologic performance targets accurately reflect the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14). The primary goal of the Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area study is to determine the predrainage hydrology and ecology of the southwest coastal environment. The Southern Estuaries Sub-Team (SET) of the Regional Evaluation Team (RET) of RECOVER is interested in potential data generated by this study to help set performance measures (PMs) for the Whitewater Bay area. This team includes clients from DOI-NPS, DOI-F&WS, NOAA, ACOE, and SFWMD. Recent data obtained by SET through the simulations run for the Initial CERP Update (ICU) have returned salinity values far in excess of any anticipated; they have therefore turned to our paleosalinity data as the potential primary tool for setting the PMs for the southern estuaries.

Additionally, this study supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects, and it provides information relevant to Landscape Modeling, Invasive Exotic Plant Detection, and Monitoring and Aquatic Exotic Animals Projects. This study supports these projects by 1) conducting research to understand the predrainage hydrology, including the amount, timing and seasonality of freshwater delivered to southwest Florida historically; 2) examining the historical environmental conditions, including the linkage between hydrology (water quality and quantity), ecology, and habitats; 3) providing the modelers with data on historic conditions in order to set targets and performance measures that reflect natural hydrologic patterns; 4) providing long-term historical data on trends and cycles within the biological component of the ecosystem that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities; and 5) by determining the timing of introduction and spread of exotics in the southwest ecosystem and the coincident changes in the native species.

This study supports the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study by addressing the questions "What were the physical and ecological conditions in . . . Shark River Slough . . .prior to drainage and modification . . ." (DOI Plan p. 63), "What are the hydrologic targets needed to mimic historic flows . . . ? (p. 63).

This study supports the Southern Golden Gate Estates Hydrologic Restoration Project by providing long-term (100-500 years) data on natural hydrologic patterns that can be used to set targets for freshwater inflows (p. 50). In addition, information on long-term changes in the biota and ongoing studies to develop our modern proxy database (used for core interpretation) will provide baseline data on the ecological responses of communities and species (p. 51).

This study supports the Southwest Feasibility Study Project by providing predrainage hydrologic and ecologic conditions that can be used to set the hydrologic targets (p. 50). The results of the core analyses will provide data on temporal and spatial patterns within the estuaries and the linkage between hydrologic conditions and ecological responses; this information can be used by the modelers (p. 50) and to determine what faunal or floral species might be used as key indicators (p. 51).

In addition, the study contributes to the Landscape Modeling project by providing historical ecological data on trends and cycles that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities. This addresses questions of the impact of increased flow (p. 63), and expected faunal and floral responses (p. 64, p. 79, p. 80). The study also contributes to the Invasive Exotic Plant Detection and Monitoring and Aquatic Exotic Animals Projects by determining the temporal and spatial distribution of exotics and changes in native species coincident with introduction (p. 118).

Status: Funding constraints prevented us from conducting any modern sampling during FY06. We have completed the processing of the cores collected in FY05 and a report describing the FY05 cores will be complete before the end of FY06. Analyses are currently underway on the FY05 cores.

Recent Products:
Wingard, G.L., Cronin, T.M., Holmes, C.A., Willard, D.A., Budet, C.A., and Ortiz, R.E., 2005, Descriptions and Preliminary Report on Sediment Cores from the Southwest Coastal Area, Everglades National Park, Florida: U.S. Geological Survey Open File Report n. 2005-1360.

Schill, W.B., 2006, Assessment Of Historical Ecological Changes Using A Molecular Approach: Greater Everglades Ecosystem Restoration Conference, June 2006.

Wingard, Budet, Hudley, Ecosystem History Database (contains modern and core estuarine data). Released to the public in Spring 2006 (http://sofia.usgs.gov/exchange/flaecohist/).

Planned Products:
Wingard, G.L., Budet, C.A., and Ortiz, R.E., 2006, Part II: Descriptions and Preliminary Report on Sediment Cores from the Southwest Coastal Area, Everglades National Park, Florida: U.S. Geological Survey Open File Report [Will be released in FY06]

Additional reports will be generated on cores collected in 2004 and 2005 as descriptions and analyses are completed. Fact sheets, talks and journal articles will follow. Data will be presented periodically as talks or posters at conferences and in meetings with client agencies. Journal articles will be completed as work progresses.

WORK PLAN

Title of Task 1: Geochronology and Paleoecology of Southwest Coastal Area
Task Funding: USGS Priority Ecosystems Science
Task Leaders: G.L. Wingard, T.M. Cronin
Phone:
GLW: 703-648-5352; TMC: 703-648-6363
FAX:
703-648-6953
Task Status (proposed or active):
Active
Task priority: High
Budget and Time Frame for Task 1: 10/03 to 9/08
Task Personnel:
T.M. Cronin, C. Holmes, M. Marot, J.B. Murray, G.L. Wingard, USGS; and contract personnel.

Task Summary and Objectives:
Human alteration of natural flow paths during the 20th century has affected the timing, quantity, and quality of water delivery to the southwest coastal zone of Everglades National Park and the Ten Thousand Islands National Wildlife Refuge. In order to restore more natural flow, it is important to understand the long-term patterns of change that have occurred in the coastal zone over biologically significant periods of time (decades to centuries).

The objectives of this task are to 1) obtain cores from the coastal zone that retain a relatively undisturbed record; 2) develop an age model for those cores; 3) develop modern proxies for interpreting the downcore assemblages, and 4) determine decadal to sub-decadal changes in salinity and freshwater influx over the last several centuries into the coastal area.

Our approach will be to 1) review previous work in the area, and conduct reconnaissance in order to locate potential coring sites along several transects; 2) investigate the current faunal and floral distribution of the area to establish proxies for downcore interpretations; 3) collect cores; 4) determine the age of the cores collected; and 5) determine the general salinity history of the coastal zone. Standard geochronologic (Pb-210 and where appropriate C-14) and paleoecologic methods (faunal assemblage analyses) will be used. Core location and collection will be coordinated with task 2, in order to obtain transects that cover the spectrum from upriver freshwater sites out to the marine coastal sites and a transect paralleling the coast from Whitewater Bay north to the Ten Thousand Island area. The first step is to obtain cores with good chronologies (i.e. the core has not been disrupted) and well-preserved faunal remains for analyses. If the core meets these criteria, then additional work can proceed. Review of earlier work in the area (Wanless, et al.) indicates obtaining good cores will not be a problem. The chronologic data will be used to interpret all additional analyses. Paleoecologic faunal assemblage analyses will be used to provide data on the general trends within the core in terms of salinity changes in water quality, nutrient supply, and the presence of subaquatic vegetation.

Task 1 - obtaining the cores, a preliminary age model, and a model of environmental change over time in the estuarine waters - is a first step toward answering the "Major Unanswered Questions and Information Needs" as discussed in the study overview above. The data from task 1 begin the process of establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the southwest coastal region. Specifically this task supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects. (See details in study overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Work to be undertaken during the proposal year and a description of the methods and procedures:
Description and processing of the cores collected in FY05 has proceeded throughout FY06. During FY07 we will focus on conducting analyses of the FY05 cores. Carbon-14 samples will be selected and sent out for analyses. Modern sampling will be conducted to build upon calibration dataset already established for living fauna and flora in other areas of south Florida and we will begin collaboration with Florida Gulf Coast University on the issue of sea level rise and its impact on the southwest coastal area.

Core analyses will follow procedures established for Florida Bay and Biscayne Bay cores, examining faunal and floral remains, sediment geochemistry and possibly shell biochemistry in radiometrically dated cores. Modern benthic surveys will be conducted during FY07. Prior work in Florida Bay has established numerous proxy organisms among the mollusks, forams and ostracodes (data available at http://sofia.usgs.gov/exchange/flaecohist/) but the environment of the southwest coast is very different. We will need to refine, modify, and potentially establish new proxies for the southwest coastal area. Modern proxy data is critical, because it allows us to accurately interpret the downcore faunal assemblages.

Core samples will be processed using standard methods and all fractions will be retained for analyses. A portion of the less than 63-micron fraction will be used for Pb-210 geochronology. The greater than 63-micron fraction will be sorted for faunal analyses; ostracodes, molluscs and benthic forams will be picked, sorted and identified. Percent abundance will be calculated for the faunal data, and these data will be compared to the modern proxy data. The down-core faunal assemblages and the presence or absence of key indicator species will allow interpretation of trends in salinity, water quality and the presence of SAV at the site. Carbon-14 analyses will be conducted as appropriate.

After the initial geochronologic and paleoecologic analyses are complete on each core, study scientists will determine if the core will be subjected to further analyses. If a core has a good chronology, and the faunal record shows evidence of distinctive changes, further analyses will be conducted (task 3 and 4). A core with out a good geochronologic record will be discarded. Work on cores collected in FY04 will continue into FY05 and additional cores will be obtained in FY05 and the same analyses repeated.

Specific Task Product(s):
Data from the cores will be compiled, analyzed, and presented as a poster or talk at conferences and meetings with clients. Additionally, all data will be made available on line at http://sofia.usgs.gov/exchange/flaecohist/. This web site provides links to data, posters and open-file reports produced by the South Florida Ecosystem History studies. Open File Reports will be produced on the cores and distributed to the clients and cooperators. As groups of analyses are completed, results will be compiled into journal articles.

Title of Task 2: Vegetational response to alterations in freshwater inflow: mangrove-freshwater marsh ecotone of southwest Florida
Task Funding:
USGS Priority Ecosystems Science
Task Leaders: Debra A. Willard
Phone: 703-648-5320
FAX: 703-648-6953
Task Status (proposed or active): Active
Task priority: Medium
Budget and Time Frame for Task 2: 10/03 to 9/08
Task Personnel: T. Sheehan, D. Willard, and contract personnel

Task Summary and Objectives:
During the 20th century, water management strategies resulted in reduced sheet flow across the Everglades, shifting the balance of fresh- to salt-water inflow along coastal zones. Although inland migration of the coastal marsh-mangrove ecotone was occurring before 20th century alterations to Everglades hydrology, it is possible that the rate of migration has accelerated since then due to reduced fresh-water flow.

This task is designed to test three hypotheses: 1) natural, climatic processes, including sea-level rise, caused inland migration of the coastal mangrove ecotone prior to the 20th century; 2) decrease in fresh-water flow from the Everglades due to water-management practices accelerated the transformation of freshwater wetlands to brackish/marine marshes and ultimately to mangrove forests; 3) restoration of natural water flow through the Everglades should stabilize regression of the ecotone to natural rates.

Task 2 - understanding the natural and anthropogenic processes affecting the mangrove and marsh ecotones of the southwest coast - contributes toward answering the "Major Unanswered Questions and Information Needs" as discussed in the study overview above. The data from task 2, in conjunction with task 1, help establish "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the southwest coastal region. Specifically this task supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects, and it provides information relevant to Landscape Modeling. (See details in study overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Work to be undertaken during the proposal year and a description of the methods and procedures:
Analyses of 2004 and 2005 cores will be completed in FY07. Cores collected in summer of FY05 will be processed and palynological analyses begun based on preliminary examination and prioritization of the cores (task 1). Pollen work will be coordinated with faunal assemblage analyses under task 1. Additional marsh core transects may be planned for collection in FY07, or material from previous collections in the area may be utilized.

We will reconstruct the position of the coastal marsh-mangrove ecotone at selected time slices during the last few centuries, with the greatest detail provided for the last century. Reconstructions will be based on analysis of pollen, seeds, charcoal, and microfaunal assemblages from sediment cores collected in a transect along Shark River from fresh water marshes to mangroves at the river mouth. (Location of transects will be coordinated with task 1.) These sites correspond to existing vegetation and SET (Surface Elevation Table) sites SH1-5 and some water monitoring sites that are part of the Tides and Inflows in the Mangrove Ecotone (TIME) study. Cores also will be collected at Big Sable Creek. Cores will be described sedimentologically before paleoecological analyses.

Based on previous radiometric dating of peat cores from the Everglades (Willard et al, 2001a; 2001b; in press), sampling intervals of 1 - 2 cm should provide adequate temporal resolution to identify vegetational and environmental changes on sub-decadal scales for the 20th century. Geochronology will be established using a combination of cesium-137 and lead-210, which provides good age control over the last 100 years, and radiocarbon dating, which provides age control over centennial to millennial time scales.

The natural variability of the system will be established through analysis of pre-drainage sediments. Globally documented climatic events may have elevated temperature as much as climate models predict for the 21st century, and an understanding of the past response of the system to such perturbations will provide important information to policymakers in designing restoration plans that incorporate expected climate variability.

Data on the timing and extent of salinity changes at the freshwater wetland-mangrove marsh ecotone will be used for calibration and verification of the TIME Study hydrodynamic and transport model being developed for the entirety of Everglades National Park. Historical salinity predictions will enable scientists conducting the TIME model development to compare the results of numerical simulations of salinity fluxes to past evidence of changes and thereby adjust critical process parameters in order to increase the accuracy of model predictions. Accurate predictions of the effects of upland water-management decisions on coastal salinities and estuarine habitat are needed to ensure the success of CERP.

Specific Task Products:
Data from cores will be compiled, analyzed, and presented as posters or talks at scientific meetings and meetings with clients. Results of this task will be compiled with results from other tasks for a journal article and a general interest publication.

Title of Task 3: Patterns, Causes, and Impacts of Salinity Changes in Southwest Coastal Zone
Task Funding: USGS Priority Ecosystems Science
Task Leaders: Thomas M. Cronin
Phone: 703-648-6363
FAX: 703-648-6953
Task Status (proposed or active): Active
Task priority: Medium
Budget and Time Frame for Task 3: 10/03 to 9/08
Task Personnel: T.M. Cronin, G.L. Wingard, J. Murray, USGS and contract personnel as assigned.

Task Summary and Objectives:
The objective of this task are to 1) determine the salinity history of the southwest coastal zone for the period prior to and following the CS&F projects using salinity proxies from sediment cores collected in transects from the coastal marsh ecotone out into the marine environment and from Whitewater Bay north to the Ten Thousand Islands (task 1). 2) Relate salinity variability to changes in fresh water flow due to land-use changes and natural variability in rainfall, freshwater runoff and water temperature (evaporation) and determine the extent to which water diversion disrupted natural patterns of salinity.

This task will build on previous work in Florida Bay and ongoing work in Biscayne Bay using ostracode, shell chemistry as a proxy to reconstruct salinities and water sources. Proxy methods that might be utilized include 1) oxygen isotope analyses of benthic organisms, 2) trace elemental (magnesium/calcium ratios) of ostracodes, 3) morphological indicators of temperature (shell size), 4) analyses of trace elements and isotopic ratios in molluscan shell layers; and 5) relative proportions of species of forams, ostracodes and molluscs indicative of specific salinity ranges (i.e. oligohaline, mesohaline, etc.)(related to task 1 assemblage analyses).

If any living large shelled clams (eg. Mercenaria) or oysters are collected during fieldwork these will be analyzed for trace elements and stable isotopes. Some of these animals may live for over a decade, so they would provide a record of recent changes that can be calibrated to water chemistry data recorded by water monitoring stations in the area. Successful reproduction of the modern salinity record in the shell record would provide levels of confidence for interpretation of the same species downcore. These species, if present in the cores, will provide a potentially continuous record of seasonal salinity changes during their lifetime. The molluscan chemistry work will build on work done in Florida Bay (Paleosalinity Study) and in the Naples area (M. Savarese, Fla. Gulf Coast Univ.; D. Surge, U. Mich.).

Task 3 - calibrating modern proxy data to the estuarine waters - is a critical part of answering the "Major Unanswered Questions and Information Needs" as discussed in the study overview above. The data from task 3 provide the details for establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the southwest coastal region. Specifically this task supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects. (See details in study overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Work to be undertaken during the proposal year and a description of the methods and procedures:
Current efforts are focused on task 1 and analyses of faunal assemblage data within the cores. Limited funding and a difficult field season prevented extensive modern surveys and calculations in FY06. We hope to resume modern collecting in FY07. In addition, we will collaborate with Florida Gulf Coast University (Dr. Michael Savarese) and share data and resources for modern calibration work.

Collection of modern samples will allow us to determine current water and shell chemistry data. Water samples and live ostracodes, molluscs, and forams will be collected during fieldwork in task 1 for the following purposes: (1) to calibrate the oxygen isotopic composition of foraminiferal shells to water isotope ratios and salinity for application to sediment core forams; (2) to determine the local radiocarbon "correction" for the southwest coastal zone. These modern calibration sites will be located along one or more salinity transects and will correspond to the modern ecology sites established in task 1 for the benthic faunal surveys. If funding and resources allow, some of these analyses will be conducted in FY07.

Specific Task Product(s):
In addition to reports listed in task 1, the following will be done: presentations to Everglades National Park personnel and South Florida Water Management District, work with TIME Study (Tides and Inflows in the Mangroves of the Everglades, R. Schaffranek) providing data on historical salinities for their models.

Title of Task 4: Geochemical History of Southwest Coastal Zone: Nutrients and Organics Task
Funding: USGS Priority Ecosystems Science
Task Leaders: William Orem
Phone: 703-648-6273
FAX: 703-648-6419
Task Status (proposed or active): Active
Task priority: Medium
Budget and Time Frame for Task 4: 10/03 to 9/08
Task Personnel: M. Corum, T. Lerch, B. Orem

Task Summary and Objectives:
Nutrients from agricultural and urban runoff are causing eutrophication and microalgal blooms in many of the estuaries in south Florida. High nutrients have been reported for the southwest coastal zone, but the source(s) of these nutrients is unknown. Debates about phosphorous limitation in eastern Florida Bay and nitrogen limitation in western Florida Bay are ongoing. The influence of Shark River slough waters on the southwest coast, and western Florida Bay, however, is not fully understood. It is important to examine both the current influx of nutrients and the historical patterns of nutrient influx into the southwest coastal zone. The effects of this excess nutrient input on biotic assemblages in this region may be substantial.

Eutrophication and microalgal blooms may be responsible for seagrass dieoff in Florida Bay, which occurred primarily in western and west-central Florida Bay. Linking eutrophication to these changes in the biotic community, however, is a difficult problem.

Our major objectives are to determine the historical record of eutrophication of the southwest coastal zone and to evaluate the linkage between eutrophication and changes in the biotic community. The results from this summary will be linked with existing work in the Everglades and Big Cypress National Preserve (Orem - Integrated Biochemical Studies in the Everglades Project).

Task 4 - determining the geochemical history of the southwest coastal region - contributes toward answering the "Major Unanswered Questions and Information Needs" as discussed in the study overview above. The data from task 4 contribute toward establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the southwest coastal region. Specifically this task supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects. (See details in study overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Work to be undertaken during the proposal year and a description of the methods and procedures:
In FY07, we will conduct analyses for C, N, P, and S on at least 4 additional cores collected in the SW coast area by Wingard and others. Results will be included in the existing SW Coast Geochemical Database. This database also includes nutrient data from upstream (Shark Slough and Big Cypress National Preserve), and nutrient, sulfur, and mercury biogeochemistry collected in the SW coastal area, as part of the Integrated Biogeochemical Processes in the Everglades Project (Orem and Krabbenhoft).

The approach we will take is to examine the historical record of nutrients from dated sediment cores. Results will also be compared to water flow records to determine if known changes in the water control system of south Florida may correspond to distinct nutrient changes within the cores. Historical changes in sulfur geochemistry of the cores will also provide information on historical changes in salinity related to construction of canals within the Everglades. Work conducted on this project will link to work being conducted in the Integrated Biogeochemical Studies in the Everglades project (Orem and Krabbenhoff), which includes: (1) studies of nutrients, sulfur, and mercury geochemistry in upstream areas of Shark Slough and Big Cypress National Preserve, and (2) studies of nutrient, sulfur and mercury biogeochemistry in the SW coastal area (Florida Bay to Rookery Bay). Results will be compiled with faunal and floral data from the project in order to reconcile the timing of changes in nutrient input to that of changes in the biological community, and to permit determination of whether eutrophication of the coastal zone and changes in biota are directly linked.

Splits of the <63-micron fraction from selected cores will be analyzed for nutrient history studies. Results from 210Pb and 137Cs dating of these cores, and paleoecological studies will be available for comparison to the nutrient data. Once cores are collected and processed, nutrients will be analyzed from selected 2-cm intervals for TC, OC, TN, and total S using a Leco elemental analyzer available in USGS biogeochemistry labs (Orem) in Reston, VA. TP content will be analyzed using a standard geochemical method involving baking at 550°C, extraction in acid, and colorimetric analysis. All equipment for this procedure is also available at USGS labs in Reston. Organic geochemical studies will involve the use of published methods. These methods involve soxhlet extraction of biomarkers from sediments, isolation procedures involving column chromatography, and identification and quantification using GC and GC/MS. All organic geochemical equipment and instrumentation needed from this work is available in lab facilities at the USGS in Reston, VA. All geochemical data will be plotted down-core, and compared to results of other tasks. Accumulation rates for TC, OC, TN, TP, and total S will be calculated using sediment accumulation rates calculated from 210-Pb dating and the concentrations of these chemical species in the sediments.

Accumulation rates for these elements in Taylor Slough and the C-111 Basin, and eastern Florida Bay have already been published by Orem. Comparison of accumulation rates in Biscayne Bay, Florida Bay, and the SW coast cores may provide additional insights into processes and flow patterns.

A USGS Open-File report on the geochemistry of SW coast sediments from cores analyzed through June 2007 will be completed by the end of FY07. Possible authorship and title: Orem W.H., Wingard G.L., Holmes C.W., Lerch H.E., Bates A.L., Corum M.D., and Marot M. (2007) Distributions of C, N, P, and S in sediments from the Southwest Coast area of the Everglades. USGS Open-File Report.

Specific Task Product(s):
Data and results will be presented at workshops, public forums, and meetings in south Florida, and ultimately will be compiled with data from other tasks to produce a journal article and general interest publications aimed at the resource managers.



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