USGS Geologic Division Continuing Project Work Plan - FY 1999

IDENTIFYING INFORMATION
Project Title: Geochemistry of Wetland Sediments from South Florida: Biogeochemistry of C,N,P, and S, Relation of S to methylation of Mercury, and Geochemical History
Location of Study Area: South Florida
Project Start Date: 10/1/94
Project End Date: 9/30/99

Project Chief: William H. Orem
Region/Division/Team/Section: Eastern/Geologic/Eastern Energy Resources/NA
E-mail: borem@usgs.gov
Phone: 703-648-6273
Fax: 703-648-6419
Mail Address: U.S. Geological Survey, National Center, ms 956, Reston, VA 20192

Program: INATURES (Formerly Ecosystems Program)
Project Number: 7230-37222

Program Element(s)/Task(s): 4.1, 4.2, 4.5, 6.1, 7.3

BACKGROUND NARRATIVES
Project Summary: This project is examining (1) sources of nutrients, sulfur, and carbon to wetlands of south Florida, (2) the important role of chemical and biological processes in the wetland sediments (biogeochemical processes) to the cycling of these elements, and (3) the ultimate fate (i.e. sinks) of these elements in the ecosystem. The focus on nutrients and carbon reflects the problem of eutrophication in the northern Everglades and Florida Bay, where excess phosphorus from agricultural runoff has dramatically altered the biology of the ecosystem. Results will be used by land and water managers to predict the fate of nutrients (especially phosphorus) in contaminated areas of the Everglades and Florida Bay, and to evaluate the long-term effectiveness of buffer wetlands being constructed as nutrient removal areas. Studies of sulfur in the ecosystem are important for understanding the processes involved in mercury methylation in the Everglades. Methyl mercury (a potent neurotoxin) poses a severe health risk to organisms in the
south Florida ecosystem and to humans, and sulfur is a key control on mercury methylation in wetland soils. Sediment studies being conducted by this project will also be used to construct a geochemical history of the ecosystem. An understanding of past changes in the geochemical environment of south Florida will provide land and water managers with baseline information on what water quality goals for the ecosystem should be, and on how the ecosystem has responded to past environmental change and will likely respond to the changes that will accompany restoration.

Project objectives and strategy: Major project objectives are as follows - (1) use isotope and other tracer methods to examine the major sources of nutrients, carbon, and sulfur to the south Florida ecosystem, (2) use geochemical methods to examine the major forms of nutrients, carbon, and sulfur in the sediments, the stabilities of the observed chemical species, and sinks of these elements in the sediments, (3) examine the biogeochemical processes controlling the cycling of nutrients, carbon, and sulfur in the ecosystem, and use geochemical modeling of porewater and sediment chemical data to determine the rates of these recycling processes, (4) develop geochemical sediment budgets for nutrients, carbon, and sulfur on a regional scale, including accumulation rates of these elements in the sediments, fluxes out of the sediments; and sequestration rates, (5) collaborate with mercury projects (USGS ACME team and others) to examine the role of sulfur and sulfate reduction in the production of methyl mercury in wetlands of south Florida, and the bioaccumulation of mercury in fish and other wildlife, (6) develop a geochemical history of the south Florida ecosystem from an examination of changes downcore in the concentration, speciation, and isotopic composition of nutrients, carbon and sulfur; use organic marker compounds and stable isotopes to develop a model of seagrass history in Florida Bay, (7) incorporate information from nutrient studies in overall ecosystem nutrient model, and results from sulfur studies in ecosystem mercury model.

This project uses both field studies and laboratory experiments to examine the biogeochemical cycling of nutrients, carbon, and sulfur in sediments. Field studies involve the collection of surface water, vegetation, sediment cores, and sediment porewater for chemical analysis. Appropriate protocols are used for the collection of samples and for chemical analysis. Sampling areas were selected to cover as wide an area as possible in the initial reconnaissance stages of the project. More recently, sampling areas were selected to reflect specific processes to be studied. Thus, samples for examining sources of nutrients and sulfur to the Everglades have focused on canals running the EAA. Biogeochemical cycling studies have focused on eutrophied and pristine sites for nutrients, and on areas of high and low methyl mercury production for the sulfur studies. Sampling sites were also chosen based on recommendations and requests from land and water management agencies. Emphasis on Taylor Slough and ENR reflects the needs of managers to understand the effects of proposed remediation efforts on the ecosystem. Isotope studies provide information on the sources of nutrients, carbon, and sulfur to the ecosystem, and information on biogeochemical cycling. Studies of nutrient, carbon, and sulfur speciation in sediments provides information on the processes occurring in sediments and on the major sinks for these elements in the sediments. Porewater studies are particularly useful for determining the major biogeochemical processes in sediments and for geochemical modeling aimed at quantitative estimates of reaction and recycling rates, and fluxes of chemical species between sediments and surface waters. Organic geochemical studies of sediments are useful for examine differences in chemical reactions among various sediments types (e.g. cattail peat and sawgrass peat), and how this may affect the ecosystem. Laboratory studies are primarily aimed at validating and extending observations from field studies. Experiments to be conducted will include: (1) laboratory decomposition of cattail and sawgrass under different simulated environmental conditions, (2) estimation of diffusion coefficients for nutrients and sulfate using a diffusion cell approach, and (3) adsorption studies of nutrients on various organic substrates (i.e. cattail peat, sawgrass peat, marl peat). Geochemical history studies emphasize analysis of dated cores, thus co-sampling with the USGS dating team is essential. Core samples are typical shared with the USGS paleontology group. Sampling sites are chosen in areas of suspected recent environmental change (e.g. lower Taylor Slough saltwater intrusion), areas of continuous sediment accumulation (Florida Bay sites), and to reflect different regions of the ecosystem.

Potential impacts and major products: This project addresses three major areas of interest to land and water managers in south Florida: (1) nutrients and eutrophication of the Everglades, (2) the role of sulfur in the methylation of mercury and its bioaccumulation, and (3) the geochemical history of the south Florida ecosystem. Our nutrient studies are focused on using isotope methods (uranium/uranium isotopes, ¹⁸O of phosphate, ¹⁵N, and ¹³C) to examine the sources of nutrients to the ecosystem, and on using sediment and porewater geochemical studies to determine the rates of nutrient recycling and nutrient sinks within the sediments. A nutrient sediment budget will be developed for incorporation in the nutrient model for the ecosystem. Results will assist managers in determining the fate of excess nutrients (especially phosphorus) stored in contaminated sediments (e.g. will the excess nutrients be buried, or recycled for movement further south into protected areas). The sediment studies will also provide managers with information relevant to the effectiveness of planned remediation methods. For example, will the type of sediments deposited in the artificial buffer wetlands or Stormwater Removal Areas (e.g. mostly cattail peat) be effective for the long-term storage of nutrients removed from agricultural runoff water? Also, what will be the effect of increased hydrologic flow from the ìreplumbingî of the canal network in the Everglades on nutrient mobility and recycling in the wetlands? How will this ìreplumbingî affect nutrient flow to the mangrove areas and Florida Bay?

Studies of sulfur within the ecosystem relate directly to the issue of methyl mercury production and bioaccumulation within the ecosystem, a serious threat to both wildlife and to the human population. Microbial sulfate reduction in wetlands (an anaerobic process) is the principal process for the methylation of mercury. Recent findings show that for south Florida wetlands methyl mercury production and bioaccumulation is highly correlated with sulfide. Thus, sulfur geochemistry plays a central role in this methylation process. Our studies are focused on examining the sources of sulfur to the Everglades using stable isotope methods (³⁴S and ¹⁸O of sulfate). Understanding the source of sulfate to the wetlands of south Florida may be a key to understanding why mercury methylation rates are so high, and on how remediation efforts in the Everglades may impact mercury methylation rates. We are also examining the sulfur geochemistry of sediments on a regional scale, with emphasis on areas that are methyl mercury ìhotspotsî. We are emphasizing co-sampling with USGS mercury researchers (ACME team).

The geochemical history component of this project will provide information on historical changes in the chemical conditions existing in south Florida wetlands. This will provide wetland managers with baseline information on the water quality goals needed to achieve ìrestorationî of the ecosystem. It will also provide land managers with an estimate of the range of water quality and environmental conditions that have affected the south florida ecosystem in the past. Geochemical history data in combination with information from paleontologic studies of the USGS paleoecology group will also provide insights on how organisms in the south Florida ecosystem have responded to environmental change in the past, and predict how these organisms will likely respond to changes in the ecosystem resulting from restoration efforts. Geochemical history studies in the southern part of the south Florida ecosystem are focused on (1) historical salinity change in the Taylor Slough area, and (2) the use of organic markers and stable isotopes to examine seagrass history in eastern Florida Bay. Both of these topics are of interest to land and water managers in south Florida.

From the beginning, one goal of this project has been to remain flexible and responsive to the needs of land and water managers in south Florida. As a result, project goals, while remaining largely intact, have been altered to reflect management and regulatory needs. This will continue to be a priority through the anticipated end date of this project.

Prior products include USGS Open-File Reports, articles in international science journals, USGS Fact Sheets, abstracts and presentations at national and international scientific meetings and at client agencies, contributions to USGS and interagency synopsis reports, databases, and the posting of reports and databases on the WWW. A complete listing of products to date is appended to the proposal.

Collaborators, Clients:
USGS Collaborators - (1) USGS ACME group (D. Krabbenhoft, J. Hurley, C. Gilmour, G. Aiken, M. Reddy, and others) for studies on the relation of sulfur to mercury methylation in wetlands of south Florida. We co-sample and exchange information with this group on a regular basis. (2) J. Harvey for studies of hydrologic flux and nutrient gradients in the Everglades and the ENR. We have coupled with Judd and exchange information. We are also exploring the possible use of uranium and uranium isotopes as a groundwater tracer in south Florida wetlands. (3) USGS paleoecology group (Brewster-Wingard, Willard, and Ishman) for ecosystem history studies. We are attempting to tie changes in downcore sediment geochemistry to historical changes in the biota. We co-sample and exchange information regularly with this team. (4) Chuck Holmes and USGS sediment dating team. We co-sample with this group and regularly exchange information. The sedimentation rates provided by Chuck are key elements of our geochemical modeling efforts. (5) USGS Florida Bay group (B. Halley and others). We have interacted with this group on our Florida Bay studies to some degree, and hope to have more interaction as we acquire more data. (6) J.K. Bohlke on nutrients in ground water.
Outside Clients - (1) D. Rudnick, F. Sklar and others (SFWMD) for our work on nutrient cycling and biogeochemical processes in Florida Bay sediments and the mangrove areas, and on the seagrass history study in Florida Bay. (2) L. Fink, P. Rawlick and others (SFWMD), . T. Atkinson and others (FDEP), R. Rice, G. Snyder and others (Univ. FL), B. GIaz and others (USDA), and sugar Industry researchers for our studies on the relation of sulfur to mercury methylation, and organic diagenesis studies in the (3) T. Armantano and others (NPS/Everglades National Park) for our nutrient and sulfur studies in Taylor Slough and Florida Bay. (4) T. Fontaine and others (SFWMD) for our nutrient studies in the Water Conservation areas. (5) F. Sklar and S. Newman (SFWMD), and Florida Fish and Game Commission for our tree island study. (6) Bill Louda (FAU) for studies of organic diagenesis and depositional history of Florida Bay.

WORK PLAN
Timeline:
FY1999- This project is scheduled to end in FY 1999, although plans for a Phase II are continuing. Thus, FY 1999 will be primarily spent completing analytical work on samples collected through 8/98, and in preparing publications including contributions to synopsis reports.

FY 1999 activities: We propose to complete activities on Phase I of this project in FY 1999. This includes: (1) completing analytical work on samples collected through 8/98, (2) completing the project database in spreadsheet (Excel) and GIS (format), and putting the database on the south Florida WWW site, and (3) completing manuscripts, including outside publications and contributions to synopsis reports. With regard to analytical work, we will complete sulfate and sulfur isotope analyses on surface water, groundwater, fertilizer, and sediment samples collected through 8/98. This work is politically sensitive since our data implicates agricultural practices with ëfate input to the Everglades which appears to be largely controlling mercury methylation in the Everglades. Completion of these analyses will be essential to support our argument for additional BMPís to apply to sulfate usage in the Everglades Agricultural area. We will also complete lignin phenol analyses of Florida Bay sediments for seagrass history studies. This approach to examining seagrass history has proved quite successful on the two cores examined to date, and we will extend the analyses to dated Florida Bay cores from central Florida Bay in FY 1999. We have been requested to complete analyses for lignin phenols from central Florida Bay cores by the SFWMD and other client agencies in south Florida. We will also complete analysis on surficial cores carefully collected in cattail and sawgrass areas of the northern Everglades to examine relative rates of decomposition and N and P recycling in cattail and sawgrass peat. This work is crucial for understanding how effective the constructed STAís will be in long-term storage of P. It is feared that the STAís will grow only cattail vegetation, and that this may not sequester P for the long-term due to the fast rates of decomposition of cattail peat. Again, client agencies have encouraged us to complete this work. Finally, analyses of surface water, porewater and sediment samples collected through 8/98 for various parameters will be completed during FY 1999 to complete our database. Analytical work in FY 1999 will be carried out by Lerch, Bates, Corum, Boylan, and Neuzil. Lerch and Bates are analytical chemists, who will do the bulk of the detailed analytical work. Neuzil is a geologist, and Boylan and Corum are student aides (part time) who will do most of the sample prep work and the routine chemical analyses.

In addition to the above analytical work to be carried out in Reston, The Menlo Park Isotope Team (C. Kendall, C. Chang, and J. Langston) will be completing isotope studies on samples collected through 8/98 during FY 1999. This will include ¹⁸O analysis of phosphate in surface water, groundwater, and peats previously collected to trace the sources of phosphate to the Everglades. This work nicely complements the uranium/uranium isotope work of Zielinski in tracing the sources of phosphate into the ecosystem. The uranium/uranium isotope and ¹⁸O on phosphate work provides the first and only direct link between phosphate from fertilizer and eutrophication in the northern Everglades. The analytical procedure for looking at  ¹⁸O in phosphate required a significant development period, but the first data from the Everglades has recently been obtained showing a definitive isotopic difference between fertilizer phosphate and background phosphate in the Everglades. The analytical work on water and sediment samples will be completed during the first half of FY 1999, and a paper completed prior to the end of FY 1999 on this topic. In addition to the ¹⁸O on phosphate work, the Menlo Park Isotope Team will complete isotope studies of sediments samples (¹³C, ¹⁵N, and ³⁴S) and groundwater samples (¹⁸O on sulfate) in collaboration with Orem et al. for determining sources and biogeochemical cycling of these elements in the Everglades and Florida Bay.

Methods and procedures to be employed will be the same ones developed over the past four years for our work in the Everglades.

The Principal Investigators on this project (Orem/Zielinski/Kendall) will spend the majority of their effort in FY 1999 in completing manuscripts. Zielinski will complete work on a manuscript on uranium/uranium isotopes as a tracer for phosphorus from fertilizer in the northern Everglades for publication in Applied Geochemistry. Kendall will complete a paper on the isotope geochemistry of south Florida wetlands for publication in a journal. Orem will complete the following papers during FY 1999: (1) Biogeochemical Cycling of
phosphorus in the Everglades (Limnology and Oceanography), (2) Biogeochemical Cycling of Sulfur in the Everglades (Limnology and Oceanography), (3) The Use of Lignin Phenols in Sediments as Indicators of Seagrass History in Florida Bay (Geochimica et Cosmochimica Acta). In addition, Orem will contribute chapters to synopsis reports on Mercury (Krabbenhoft), Florida Bay (Halley), and possibly Ecosystem History (Wardlaw).

Finally, completion of a database for the project will be a major effort for FY 1998. This work will be primarily completed by Orem and two student aids (Corum and Boylan). Data will be available in both spreadsheet (Excel) and GIS (ARCview format). The database will be placed on the south Florida WWW site for public access.

FY 1999 deliverables/products: Papers from this project for submission to international journals during FY 1999 will include: (1) Biogeochemical Cycling of Phosphorus in the Everglades, Orem et al. (Limnology and Oceanography), (2) Biogeochemical Cycling of Sulfur in the Everglades, Orem et al. (Limnology and Oceanography), (3) Lignin Phenols in Sediments as Indicators of Seagrass History in Florida Bay, Orem et al. (Geochimica et Cosmochimica Acta), (4) Uranium and Uranium Isotopes as Tracers of Phosphorus from Fertilizer in the Northern Everglades, Zielinski et al. (Applied Geochemistry), and (5) Stable Isotopes as Tracers of Biogeochemical Cycling in the Everglades Kendall et al. (to be determined). Contributions to Synopsis Reports will include: (1) Sources of Sulfur and Sulfur Cycling in the Everglades, W.H. Orem (Mercury Synopsis), (2) Geochemistry of Florida Bay Sediments, W.H. Orem (Florida Bay Synopsis), and (3) Geochemical History of the Everglades and Florida Bay (Paleoecology Synopsis). In addition, the principal Investigators (Orem/Zielinski/Kendall) will give presentations and prepare abstracts for meetings during FY 1999. Orem will also prepare a Fact Sheet on the Geochemistry of Florida Bay Sediments in FY 1999. Finally, a database will be completed during FY 1999 for posting on the WWW.

FY 1999 outreach: Client needs are being addressed in a number of different ways: (1) frequent calls and visits to collaborators, (2) presentations at science conferences and program reviews in south Florida, (3) presentations USGS meetings in south Florida(4) distribution of reports to interested clients. A database will be completed in FY 1999 for placement of the south Florida WWW site for public access. Orem will contribute to a Fact Sheet on Mercury to be completed by Krabbenhoft (USGS-Madison, WI) during FY 1999. Orem also plans a Fact Sheet on Florida Bay for FY 1999.

New directions or major changes for FY 1999: The project will shift from field-intensive investigations, to completion of analytical work and writing reports. One relatively new area is tree island research studies. This work is being conducted in collaboration with Deb Willard (USGS), Chuck Holmes (USGS), F. Sklar and S. Newman (SFWMD), and scientists from the Florida Fish and Game commission. A number of tree islands were sampled in 4/98, and a modest amount of travel money has been allocated for possible brief follow-up work in FY 1999. Tree islands are an area of current intense interest in south Florida, and may be a major emphasis in Phase II studies. USGS will have the first paleoecology and geochemical data from tree islands in the Everglades.
 

ACCOMPLISHMENTS, OUTCOMES, PRODUCTS, OUTREACH
FY 1998 accomplishments and outcomes, including outreach: Major research findings during FY 1998 included the following: (1) Sulfate and stable isotope data (³⁴S and ¹⁸O showed that the major source of sulfate to the northern Everglades is canal water draining the Everglades Agricultural Area (EAA), probably from the use of agricultural sulfur fertilizer. This is of major importance since sulfur geochemistry largely controls the methylation of mercury in the Everglades. Application of BMPís with regard to the use of agricultural sulfur in the E.A.A may be a useful management tool for reducing mercury methylation in the Everglades. A paper is currently in review (Nature) (2) Results of our Florida Bay work show that recent nutrification has occurred in eastern and central Florida Bay beginning in about 1980. This corresponds to the period of first reports of seagrass die off and microalgal blooms in Florida Bay. This information represents the first reports of recent nutrification in Florida Bay. A paper on this is currently in review (J. Coastal Research). (3) A dataset in GIS format on C,N,P, and S accumulation rates in the Everglades has been completed. This dataset will be of great utility to ecosystem modelers and managers, and is the first of its kind for the Taylor Slough area. An open-file report is currently in review. (4) Uranium/uranium isotope work continues to verify that the major source of phosphorus to the ecosystem is from fertilizer discharged to the marshes in canal water. A paper is currently in preparation (Applied Geochemistry). (5) A method for analysis of ¹⁸O on phosphate has been successfully developed and is currently being used in analysis of surface water and sediments from the Water Conservation Areas. The method will be useful for tracking the sources of phosphate within the ecosystem. Analyses will continue into FY 1999, and a paper on this will be forthcoming in FY 1999. (6) Isotopic data (¹³C, ¹⁵N, ³⁴S) on sediments and biota from throughout the Everglades and Florida Bay has been completed in collaboration with researchers from EPA. GIS type maps of the distributions have been compiled showing trends related to food chain dynamics and redox conditions. Several presentations on this have been made and a paper will be forthcoming in FY 1999. (7) Intensive field sampling will be completed with the scheduled 7/98 fieldtrip. A total of 15 fieldtrips were conducted during the 4 years of this project (FY 1995 ó FY 1998), covering the Everglades from north of Lake Okeechobee to Florida Bay, and from the Water Conservation Areas to Big Cypress Preserve. A number of intensive sampling sites were established and visited up to 8 times seasonally over the course of the project. The number of different sampling sites totals more than 80. Sampling of sediments, porewater, surface water, groundwater, fertilizer (5 different sites), agricultural soil, and vegetation was conducted to answer the hyotheses posed by this project. (8) Outreach activities during FY 1998 included the posting of Fact Sheets and publications on the WWW and presentations at client agencies in south Florida.

FY 1998 deliverables, products completed:
Orem W.H., Lerch, H.E., and Holmes C.W. (1998) History of nutrification and seagrass abundance from geochemical studies of sediment cores from eastern Florida Bay. Int. J. Coastal Geology, in review.

Bates A.L., Spiker E.C., and Holmes C.W. (1998) Speciation and isotopic composition of sedimentary sulfur in the Everglades Water Conservation Area 2A, Florida, USA. Chemical Geology, in press.

Orem W.H., Lerch H.E., Holmes C.W., Corum M., Boylan A., Bates A., and Hedgman C. (1998) Geochemistry of sediments from USGS cores in Taylor Slough, 1996. USGS Open-File Report, in review.

Bates A.L., Orem W.H., Harvey J.W. and Spiker E.C. (1998) Sources of sulfate to the northern Everglades. Nature, in review.

Bates A.L., Orem W.H. and Harvey J.W. (1998) Sulfate in the northern Everglades: Concentrations and sulfur isotopic composition [abs.]. AGU Spring Meeting, Boston, MA, May 1998, in review.

Orem W.H., Bates A.L., Lerch H.E. and Harvey J.W. (1998) Sulfur geochemistry of the Everglades: Sources, sinks and biogeochemical cycling. South Florida Mercury Science Program Annual Workshop, West Palm Beach, FL, May 1998, Abstracts with Program.

Orem W.H., Lerch H.E., Corum M., Boylan A., Hedgman C., and Zielinski R. (1998) Phosphorus geochemistry of the south Florida wetlands ecosystem: Sources and biogeochemical cycling [abs.]. AGU Spring Meeting, Boston, MA, May 1998, in review.

Orem W.H., Holmes C.W., Kendall C., Lerch H.E., Bates A.L., Boylan A. and Corum M. (1998) Geochemistry of Florida Bay sediments: Investigation of nutrient and seagrass history. Annual Florida Bay Science Conference, Miami, FL, May 1998, Extended abstract with Program, 3 pp.
 
Orem W.H., Bates A.L., and Lerch H.E. (1997) The biogeochemistry of sulfur in the northern Everglades-Sources, cycling and relation to mercury methylation [abs.]. 4th International Symposium on Environmental Geochemistry, Vail, CO, October 1997.

Zielinski R.A., Simmons K.R., and Orem W.H. (1997) Uranium and uranium isotopes as tracers of nutrient addition: A case study in south Florida [abs.]. 4îí International Symposium on Environmental Geochemistry, Vail, CO. October .1997.

Orem W.H. (1998) Geochemistry of Florida Bay sediments. Management Presentation at South Florida Water Mamagement District, West Palm Beach, FL, May 1998.

Orem W.H., Lerch H.E., Bates A.L., Boylan A., Corum M. and Hedgman C. (1998) Organic geochemical studies of Florida Bay sediments: Application to problems of eutrophication and seagrass history. International Coastal Symposium, Palm Beach, FL, May 1998, Abstracts with Program.

Kendall C., Silva S. and Chang C. (1998) Isotope studies in the Everglades: Food webs, mapping of redox conditions, and phosphates. South Florida Mercury Science Program Annual Workshop, West Palm Beach, FL, May 1998, Abstracts with Program.

Kendall C., Silva S.R., Stober Q.J. and Meyer P. (1998) Mapping spatial variability in marsh redox conditions in the Florida Everglades using biomass stable isotopic compositions. AGU Spring Meeting, Boston, MA, Abstracts with Program.
 

PROJECT SUPPORT REQUIREMENTS
Names and expertise of key project staff:
FY 1999- Reston, VA: William H. Orem (project chief/geochemist), Harry E. Lerch (analytical chemist), Anne L. Bates (sulfur chemist/isotope chemist), Sandra Neuzil (geologist), Margo Corum (student aid-laboratory and data support), Ann Boylan (student aid-laboratory and data support). Denver, CO: Robert Zielinski (geochemist-uranium and uranium isotope geochemistry). Menlo Park, CA: Carol Kendall (res. hydrologist-stable isotope geochemistry), Cecily Chang (res. Hydrologist-stable isotope geochemistry), J. Langston (hydrologic tech.-stable isotope geochemistry).

All expertise needs are staffed in project or are acquired by collaboration with other USGS projects, or collaboration with researchers in outside agencies (e.g. SFWMD, FDEP, FGS, USEPA, NPS, USFWS, USDA). Principal expertise needs include: organic chemistry, porewater geochemistry, sulfur geochemistry, isotope geochemistry, uranium geochemistry, geochemical modeling, GIS computer data handling (support from Mark Levine, EERT, Reston, VA), trace metal geochemistry, mercury geochemistry and
microbiology (collaboration with USGS ACME team), paleoecology (collaboration with USGS paleoecology group), hydrology (collaboration with Judd Harvey-USGS, and SFWMD), agricultural fertilizer usage (collaboration with B. Glaz, USDA, Ron Rice/George Snyder, Univ. of Florida).

Other required expertise for which no individual has been identified: None.

Major equipment/facility needs: Geochemical laboratories are located in Reston, VA. Stable Isotope laboratories are located in Reston, VA and in Menlo Park, CA. Uranium laboratory is located in Denver, CO. No new major equipment needs anticipated for FY1999.

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