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Aquatic Cycling Of Mercury in the Everglades (ACME)

Project Proposal for 1999

Project title: A Proposal for Synthesis by the Aquatic Cycling Of Mercury in the Everglades Project
Geographic area: WCA1, WCA2, WCA3, Everglades National Park, and the ENR Area
Project start date: October 1, 1998
Project end date: September 30,2000

Project chief: David P Krabbenhoft
Region/Division/Team/Section: NR, WRD, Wisconsin District Office, Mercury Studies Team
Email: dpkrabbe@usgs.gov
Phone: 608-821-3843
Fax: 608-821-3817
Mail address: USGS-WRD, 8505 Research Way, Middleton, WI 53562

Program(s): INATURES Program

Program element(s)/task(s) and percent time commitment to each task:
Element 4: Regional Mercury, Geochemnistry and Water Quality Assessment

  • Task 4.1 (70%) Chemical and biochemical controls of mercury transformation, speciation, transport, storage and bioavailability in the Everglades.
  • Task 42 (2%) Geochemical processes and in organic rich sediment nutrients, history and diagenesis.
  • Task 4.3 (2%) Microbial mercury degradation in the south Florida Ecosystem.
  • Task 4.4 (10%) Interactions of Hg and DOC in the Everglades.
  • Task 4.5 (10%) Mercury Cycling in the Everglades and the Everglades Nutrient Removal (ENR) Areas
  • Task 4.6 (6%)-Groundwater/surface-water interactions.
 

BACKGROUND NARRATTVES
Project summary: The toxicological manifestation of mercury contamination varies widely among ecosystems; some ecosystems show little transference of mercury to the food web (bioaccumulation), while others show efficient transfer into living organisms. Such is the case with the Florida Everglades. For the past three years, the Aquatic Cycling of Mercury in the Everglades (ACME) project has been investigating the factors controlling mercury cycling and bioaccumulation. The objective this proposed work is to bring to fruition the research conducted by the ACME project. Products from the synthesis (databases, scientific papers, overall synthesis document) will be valuable for State of Florida managers who are currently making restoration design decisions. In addition, because mercury is globally distributed, our results will be transferable worldwide to other scientists and ecosystem managers.

Project objectives and strategy: The Aquatic Cycling of Mercury in the Everglades (ACME) project was originally designed to examine the reasons behind the observed high levels of mercury in predatory fish across most at the Everglades, and to do so by focusing on fundamental biogeochemical processes. The overall goal of the ACME project was to provide information that would be useful to state and federal management agencies responsible for making Everglades restoration plans, and to hopefully include strategies for reducing mercury toxicity to this fragile ecosystem. Originally, the scientific breadth of the ACME project was limited to critical areas of study central to the mercury contamination issue. After initiation of field studies in 1995, however, substantial information gaps in many basic areas of ecosystem research were revealed for the Everglades (e.g,, hydrology, microbiology! and food web studies). As a result, the scope of our effort was expanded to what now is a more complete, general study of biogeochemistry of the Everglades ecosystem. In addition, our geographic coverage was expanded from original plans that called for focusing on just the northern Water Conservation areas, to now, where we sample a complete north-to-south transect of the remaining Everglades (Loxahatchee National Wildlife Refuge to Taylor Slough).

ACME study results to date have resulted in four refereed journal papers (with four others currently either submitted or in preparation stages) and many presentations at national and international meetings (see ACME Project Bibliography). While these products have provided a start toward our synthesis goals, most of our major research findings will be produced under this proposed synthesis effort. We will accomplish our synthesis goals by three principal means: (1) coalescing and uploading project data to the Web via a data server, (2) preparation and publication of manuscripts in high-quality, peer-reviewed journals, and (3) preparation and publication of a overall project synthesis document that brings together all of the scientific highlights of the ACME publications in to a uniform conceptual model/framework, and that is presented in a fashion that will be useful to ecosystem managers. Each of these synthesis activities is discussed in more detail below. To help catalyze the manuscript production process we propose to have a project meeting early in FY99. Each primary investigator would come to the meeting with a series of proposed manuscripts, complete with authors, titles and an outline. Manuscript working groups would be formed at the meeting to produce extended outlines for each manuscript. Dave Krabbenhoft will assume lead responsibility for coordinating the synthesis phase of the ACME project, although the ultimate success of this effort will depend on the self-motivation and desire of all Principal Investigators to fully engage and commit themselves to this activity. Details of each of the three main synthesis activities arc given below.

1. Web Enabled Data Base: Most of the data collected on mercury in water during the past 3.5 years is already uploaded onto a data server located in the Wisconsin District Office. An OracleTM  interface is already operational for providing data over the Internet (http://oraddwimdn.er.usgs.gov/ows-bin/owa/mercury.info), and will be "fine tuned' and improved with graphics during the summer of 1998. By the end of FY98, all of the aqueous mercury data will be included into this data base and available to the public. Some of the original data would be inappropriate or difficult to upload, such as experimental results to determine process rate coefficients. In those cases, figures or charts that present experimental results that could be useful to others will be included on the Web site. The Web server will have a SEQL-based, user-friendly, graphical interface that will contain "hot keys" that will provide general project information, site maps, listings of project products, site photographs, as well as links to the main INATURES Program web site and the South Florida INATURES site.

2. Journal Paper Production: Each of ACME Principal Investigators will be expected to draft, acquire approval, submit and get published 1 to 4 journal papers during the synthesis period. The project leader has encouraged all of the Principal Investigators to begin drafting manuscripts immediately, rather than waiting for the formal synthesis year. We will target high quality journals such as Environmental Science and Technology, Environmental Chemistry and Toxicology, Limnology and Oceanography, Geochemica Cosmochemica Acta, Chemical Geology, Hydrologic Processes, and Biogeochemistry. The Editor of Hydrologic Processes has already been consulted about the possibility of submitting a compendium of papers from the ACME project, and having them be published as a dedicated volume of that journal. This inquiry was very well received by the Editor, and the possibility of the ACME team taking this publication approach will be discussed as a group following the June, 1998 field trip. Each of these papers will focus on specific aspects of each of the Principal Investigator's research programs. It is expected that many of these papers will not focus on mercury per se, and several of them may not mention mercury at all. For example, a team of authors has already been assembled to being the process of drafting a paper addressing the redox status of Everglade's sediments, a very important research finding from ACME, but not necessarily tied to mercury cycling.

3. Preparation of Overall Synthesis Document: There are many target audiences for our data and interpretations. Ecosystem managers are more likely to be interested in knowing how all our individual results tie together into a coherent and consistent conceptual framework and what implications they have for restoration plans. Essentially this will entail the coalescing of all of the individual papers produced under item 2 above, as well as any other information previously published or not included in those papers but useful for the document. In addition, other related work such as mercury toxicity testing on avian populations from the everglades that is now underway at the Patuxent Wildlife Center will be included in this document. The anticipated outlet will be a USGS Circular (or similar publication series) that will allow for a flexible presentation of ACME research to date and include colorful graphics and photographs. Individual chapters will be short and concise (3-5 printed pages). An outline for this document follows. [A suggested lead author is indicated, although it is anticipated that all the chapters will have multiple authors]

The Aquatic Cycling of Mercury in the Everglades (ACME) Project; A Biogeochemical Assessment of the Florida Everglade Ecosystem

  • Introductory materials including of why the project was initiated, project goals, interagency collaboration, and a brief description of the Everglades ecosystem and history. (Krabbenhoft)
  • Hydrogeological setting and groundwater-surface water interactions in the Everglades ecosystem. (Harvey)
  • Cycling of sulfur and nutrients in the Everglades ecosystem. (Orem)
  • Sedimentary diagenesis in the Everglades ecosystem. (Orem)
  • General porewater chemistry in the Everglades ecosystem. (Reddy)
  • Sedimentary redox chemistry in the Everglades ecosystem. (Schuster)
  • DOC importance, generation, and evolution in the Everglades ecosystem; Is this the Everglades master variable? (Aiken)
  • Mercury in surface waters of the Everglades ecosystem. (Burley)
  • Mercury methylation in the Everglades ecosystem. (Gilmour)
  • Methylmercury degradation in the Everglades ecosystem. (Marvin- Dipasquale)
  • Humic substances-Hg interactions: controls on levels, speciation, and transport (King)
  • Photo-chemistry of mercury in the Everglades ecosystem. (Krabbenhoft)
  • Analytical challenges of Everglades waters for mercury analysis. (Olson)
  • Pigments as diagnostic indicators/descriptors of periphyton in the Everglades. (Hurley)
  • Delineation of the Everglades ecosystem food webs; the stable isotope approach (Kendall)
  • Bioaccumulation of mercury in lower tropic levels of Everglades ecosystem. (Cleckner)
  • Bioaccumulation of mercury in predatory fish of the Everglades ecosystem. (Lange).
  • Toxicological Effects of Mercury on Wading Birds from the Everglades (Heinz, Patuxent Wildlife Center)
  • The Everglades Mercury Cycling Model. (Harris)
  • Summary (All)
 
 
 
Potential impacts and major products: Our scientific results have already had many impacts on the general scientific community, including several novel contributions toward the understanding of mercury in the environment.
  • A demonstration of significant diel changes in mercury phase and species shifts that occur reproducibly on a diel basis.
  • A demonstration that floating and attached periphyton can methylate mercury, and likely serves as a primary entry point of mercury to the food web.
  • Through the use of pigment (major and ancillary) analysis, determination of what microbial communities promote mercury methylation in periphyton, and also a more general description of the microbial ecology of Everglade's periphyton that was heretofore not known.
  • Demonstrated case of where too much available sulfate can lead to excessive sulfide levels that drive the separation of mercury toward an anionic form (HgS22) that is not available for methylation. This finding has profound impacts on our understanding as to why the eutrophied areas of the Everglades exhibit reduced levels of bioaccumulation than more pristine areas.
  • We have published an analytical improvement paper on the effects of high sulfide levels, and its interference effects on methylmercury determinations. This effect was heretofore unknown.
  • Demonstration of dual microbial methylmercury degradation pathways (oxidative and reductive) that is largely mediated by the same microbes that methylate mercury (sulfate reducing bacteria). In addition, the microbial demethylation studies have greatly improved existing methodological assays by conducting measurements at near ambient methylmercury levels.
  • Demonstration of photochemical degradation of mercury by photolysis, which was previously unknown in the Everglades ecosystem.
  • Demonstration of micro-chemical stratification of the marshes in the Everglades. These results have widespread impacts on how managers and other scientists must view the Everglades from a conceptual model standpoint, as well as what regulates the overall biogeochemistry of the Everglades. Many previous investigators would have preferred to view the ecosystem as a wide, slow moving river; whereas our findings would suggest that from a biogeochemical perspective, a vertically-oriented, stratified-marsh model is more appropriate, similar to a stratified lake.
  • Previous to the ACME project, existing wisdom held that Everglade's sediments were oxic (so called sweet peat). We have successfully demonstrated that in fact these sediments are at most oxic in micro zones around roots, but primarily anoxic and the dominating biogeochemical process are anoxic.
  • Many previous studies involving mercury have shown correlative responses of mercury and DOC in natural systems. The ACME project has substantially improved our level of understanding of the fundamental chemical reasons for these observations.

From a management perspective, results from the ACME project have and will play a major role in making restoration decisions for the Everglades. Important contributions include:

  • A reliable data base of mercury concentrations in air, water, sediment, biota collected over a 3.5 year petiod that will serve as a baseline for future studies and upon which target legislation can be based. For example, TMDL standards are currently being deliberated and, for mercury at least, provide a direct link to existing and proposed Clean Air Act Laws. Law makers need to consider the fact that with the existing levels of mercury arriving to the Everglades via atmospheric pathways, all game fish in the ACME field area are above the human consumption advisory limit for mercury. This poses the question of "what is an allowable air emission load of mercury in south Florida?"
  • As mandated by the Florida Everglades Forever Act, by December 31, 1998, the South Florida Water Management District must provide a report to the Florida Legislature on the status and current understanding of the mercury problem in the Everglades. By December 31, 1999, recommendations of what to do about the problem must be made to the Legislature. ACME data will provide the basis of much of what will be included in these reports.
  • The US Army Corps of Engineers is currently designing the restoration plan for south Florida, and one consideration they and other agencies must consider is what effect these alterations will have on mercury toxicity. Data and reports from the ACME project will play a fundamental role in making recommendations to the Corps and how they can mitigate mercury toxicity impacts.

Collaborators, clients: Internal collaborators and participants on the proposed synthesis phase of the ACME project and external clients of the synthesis are listed in Tables 1 and 2 respectively.

Table 1. Internal Collaborators and anticipated synthesis participants for the AMCE project

CollaboratorAffiliationAreas of Study
George AikenUSGS, WRD, Boulder, CODOC chemistry-Hg interactions
Lisa ClecknerUniv. of Wisconsin, MadisonBioaccumulation of Hg
Cindy ClecknerAcademy of Natural SciencesMercury methylation
Reed HarrisTetra Tech, Inc.Hg cycling model
Gary HeinzUSGS, BRD, Patuxant CenterToxicity studies in wildlife
Jud HarveyUSGS, WRD, Reston, VAGW-SW interactions
Jim HurleyWisc. DNR, Madison,WIHg chemistry and pigments
Carol KendallUSGS, WRD, Menlo Park, CAStable isotopes and food webs
Sue KingUniv. of Wisconsin, MadisonHumics and Hg/MeHg
David KrabbenhoftUSGS, WRD, Madison, WIAqueous Hg chemistry
Mark Marvin-DipasqualeUSGS, WRD, Menlo Park, CAHg demethylation
Mark OlsonUSGS, WRD, Madison, WIHg analysis of Everglades waters
Bill OremUSGS, GD, Reston, VAS cycle, nutrients and diagenesis
Ted LangeFlorida Game and Fish Comm.Bioaccumulation of Hg
Michael ReddyUSGS, WRD, Boulder, COModeling DOC-Hg interactions
Paul SchusterUSGS, WRD, Boulder, CORedox/porewater chemistry

Table 2. External Clients of the ACME project.

CollaboratorAffiliationManagement Responsibility
Sarah GerouldUSGS, Reston, VAINATURES Prog. Manager
Aaron HigerUSGS, W. Palm Beach, FLS. Florida Ecosystem Prog. Mgr.
Larry FinkS. Florida Water Mgt. DistrictSFWMD Mercury Program
Tom AtkesonFlorida Dpt. of Environ. Prot.FDEP Mercury Coordinator
Richard PunnetUS Army Corps EngineersRe-study Coordinator
Richard HarveyUSEPAS. Florida Prog. Manager
The Interagency Working GroupMultiple agenciesScientific and managerial decisions
of government scientific activities
John and Jane DoeUS CitizenConcerns for Fish Contamination

WORK PLAN
Overall: See Objectives and Strategy section above.

Time line: FY 1999 to project end):

 Fiscal Year-Quarter
TaskFY98-3FY98-4FY99-1FY99-2FY99-3FY99-4FY00-1FY00-2FY00-3FY00-4
Web site data enable******       
Individual Journal Papers ************   
ACME Circular  ************** 

Deliverables/products: See Objectives and Strategy section above.

Outreach activities: Over the past 3.5 years, ACME project investigators have been regular attendees at a variety of interagency and scientific meetings. Dave Krabbenhoft is a sitting member of the South Florida Mercury Science Program Committee and attends their biannual meetings on behalf of ACME. The SFWMD and FDEP annually host a Mercury Program Peer Review meeting, where typically 10-12 technical presentations (about 50% of the total program) are made by ACME investigators. We have been active at scientific meetings throughout the history of our project and anticipate keeping the commitment to get our scientific finding out quickly to our peers by attending two national meetings during this proposed synthesis period.

PROJECT SUPPORT REQUIREMENTS
Names and expertise of key project staff: Staffing requirements requested here only include those activities centered out of the Wisconsin District Office.
 

  • Dave Krabbenhoft, (75%) Geochemistry, FY99, FY00
  • Jim Hurley, (50%) Chemistry. Senior Scientist, Wisc. DNR no charge to USGS, FY99 & FY00
  • Lisa Cleckner, (80%) Univ. of Wisc. Postdoc., FY99
  • Sue King, (70%) Geochemistry, [Sue's salary has been funded for first three years of project by a NSF proposal co-written by USGS and U. of Wisconsin, request funding for Sue to finish writing thesis and participate in synthesis] FY99
  • Paul Garrison, Research Scientist, WDNR (20%) no charge to USGS, FY99
  • Mark Olson, (25%) Data verification, analytical methods development1 and sample analyst, FY99
  • John Dewild, (25%) Sample analyst, FY99
  • Harty House, (4.5%) Web data base facilitator, FY99
 
 
Major equipment/facility needs (list by fiscal year for duration of project): Request a new PC for synthesis leader to better facilitate manuscript production and data base distribution. Currently using a 5 year old 486 PC.
 
 
 
 
 
 
ACME Project Bibliography

Papers:

  • Krabbenhoft, D.P., Mercury Studies in the Florida Everglades, 1996, U.S. Geological Survey Fact Sheet, P5-166-96 (4 p).
  • Krabbenhoft, D.P., and others, The South Florida Mercury Science Program, 1997 Florida Department of Environmental Protection Fact Sheet.
  • Krabbenhoft, D.P., J.P. Haley, M.L. Olson and L.B. Cleckner, 1998, Diel variability of mercury phase and species distributions in the Florida Everglades.Biogeochemistry, 40, pp. 311425.
  • Hurley, J.P., D.P. Krabbenhoft, L.B Cleckner, M.L. Olson, G. Aiken, and P.J. Rawlik, 1998, System controls on aqueous mercury distribution in the northern Everglades. Biogeochemistry, 40, pp. 293-310.
  • Cleckner, L.B. P.J. Garrison, J.P. Harley, M.L. Olson and D.P. Krabbenhoft, 1998. Trophic transfer of methylmercury in the northern Everglades, Biogeochemistry, pp. 347-361
  • Olson, M.L., L.B. Cleckner, [J.P. Hurley, D.P. Krabbenhoft, and T.W. Heelan, 1998, Resolution of matrix effects on analysis of total and methyl mercury in aqueous samples from the Florida Everglades, Fresenius J. Analytical Chemistry, 358, p. 392-396.
  • Gilmour, CC., G.A. Gill, M.C. Stordal and E. Spiker, 1998, Mercury methylation and sulfur cycling in the Northern Everglades. Biogeochemistry, pp. 326-346.
  • M. Marvin-DiPasquale and R.S. Oremland, 1998, Bacterial Methylmercury Degradation in Florida Everglades Sediment and Periphyton, (manuscript submitted to Environmental Science and Technology)
  • Cleckner, L.B., C.C Gilinour, J.P. Hurley, and D.P. Krabbenhoft, 1998, Mercury Methylation by Periphyton in the Florida Everglades, (manuscript submitted to Limnology and Oceanography)
  • Ravichandran, M. G.R. Aiken, M.M. Reddy, and J.N. Ryan, Enhanced Dissolution of Cinnabar (Mercuric Sulfide) by Organic Matter from the Florida Everglades, (manuscript submitted to Environmental Science and Technology).
  • Orem W.H., H.E. Lerch, and P. Rawlik, 1997, Geochemistry of surface and pore water at USGS coring sites in wetlands of south Florida. USGS Open-File Report 97-454, 55pp.
  • Bates A.L., E.C. Spiker, and C.W. Holmes, 1998, Speciation and isotopic composition of sedimentary sulfur in the Everglades Water Conservation Area 2A. Florida, USA. Chemical Geology, in press.

Abstracts:

  • Krabbenhoft., D.P., J.P. Hurley, M.L. Olson, and L.B. Cleckner, 1996, Mercury transformation processes in the Everglades: temporal variations in mercury phase and species distribution and controlled exposure experiments, (abs) Proceedings of the Fourth International Conference on Mercury as a Global Pollutant, August 4-8, 1996, Hamburg, Germany.
  • Olson, M.L., D.P. Krabbenhoft, L.B. Cleckner, and J.P. Hurley, 1996, Resolution of matrix effects on analysis of total and methyl mercury in aqueous samples from the Florida Everglades, (abs) Proceedings of the Fourth International Conference on Mercury as a Global Pollutant, August 4-8, 1996, Hamburg, Germany.
  • Hurley, J.P., D.P. Krabbenhoft, G. Aiken, M.L. Olson, and L.B. Cleckner, 1996, System controls on water column total and methyl mercury in the northern Everglades(abs) Proceedings of the Fourth International Conference on Mercury as a Global Pollutant, August 4-8, 1996, Hamburg, Germany.
  • Cleckner, L.B., P.J. Garrison, J.E. Hurley, D.P. Krabbenhoft, M.L. Olson, and T. Heelen, Relations between water chemistry and trophic transfer of mercury in the northern Everglades, (abs) Proceedings of the Fourth International Conference on Mercury as a Global Pollutant, August 4-8, 1996, Hamburg, Germany
  • King, S.A., C.J. Miles, D.P. Krabbenhoft, J.P. Hurley, and L.A. Fink, 1997, Mercury studies in the Everglades Nutrient Removal Area, (abs), Proceedings of the Fourth International Conference on Mercury as a Global Pollutant, August 4-8, 1996, Hamburg, Germany.
  • Krabbenhoft, D.P., J.P. Hurley, M.L. Olson, and L.B. Cleckner, 1996, Sunlight-induced, temporal variations in mercury phase and species distributions in the marshes of the Florida Everglades, (abs) American Chemical Society, national meeting, Program with Abstracts, Orlando. FL, August 23-28, 1996.
  • Hurley, J.P., D.P. Krabbenhoft, L.B. Cleckner, S.A. King and M.L. Olson, 1996, System controls on the aqueous mercury distribution in the northern Everglades, (abs)American Chemical Society, national meeting, Program with Abstracts, Orlando, FL, August 23-28, 1996.
  • Cleckner, L.B., P.J. Garrison, J.P. Hurley, D.P. Krabbenhoft, M.L. Olson, and T. Heelen, 1996, Relations between water chemistry and trophic transfer of mercury in the northern Everglades, (abs) American Chemical Society, national meeting, Program with Abstracs, Orlando, FL, August 23-28, 1996.
  • Krabbenhoft, D.P., J.P. Hurley, M.L. Olson, and L.B. Cleckner, 1997, The aquatic cycling of mercury in the Everglades (ACME) project: Results from the first two years of study, (abs), American Society of Limnology and Oceanography, national meeting, Santa Fe, NM, February 10-14, 1997.
  • Cleckner, L.B., J.P. Hurley and P.J. Garrison, D.P. Krabbenhoft and M.L. Olson, 1997, The role of periphyton in mercury bioaccumulation in the Florida Everglades, (abs), American Society of Limnology and Oceanography, national meeting, Santa Fe, NM, February 10-14. 1997.
  • Gilmour, C.C., G.A. Gill, M.C. Stordal and E. Spiker, 1997, Controls on mercury methylation in the Northern Everglades, (abs) American Society of Limnology and Oceanography, national meeting, Santa Fe, NM, February 10-14, 1997.
  • Krabbenhoft, D.P, Hurley, J.P., M.L. Olson, and L.B. Cleckner, 1997, System controls on the aqueous mercury distribution in the northern Everglades, in U.S Geological Survey Program on the South Florida Ecosystem - Proceedings of the Technical Symposium in Ft. Lauderdale, Florida, August 25-27, 1997; U.S. Geological Survey Open-File Report 97-385, p. 62-63.
  • Krabbenhoft, D.P, Hurley, J.P., M.L. Olson, and L.B. Cleckner, 1997, Mercury transformation processes in the Everglades: Temporal variations in mercury phase and species distributions and controlled exposure experiments, (abs) in U.S. Geological Survey Program on the South Florida Ecosystem - Proceedings of the Technical Symposium in Ft. Lauderdale, Florida, August 25-27, 1997; US.. Geological Survey Open-File Report 97-385, p. 63-64.
  • Cleckner, L.B., J.P. Hurley and P.J. Garrison, D.P. Krabbenhoft and M.L. Olson, 1997, The role of periphyton in mercury bioaccumulation in the Florida Everglades.(abs), in U.S. Geological Survey Program on the South Florida Ecosystem - Proceedings of the Technical Symposium in Ft. Lauderdale, Florida, August 25-27, 1997; U.S. Geological Survey Open-File Report 97-385, p. 64-65.
  • Olson, M.L., D.P. Krabbenhoft, L.B. Cleckner, and J.P. Hurley, 1996, Resolution of matrix effects on analysis of total and methyl mercury in aqueous samples from the Florida Everglades, (abs), in U.S. Geological Survey Program on the South Florida Ecosystem - Proceedings of the Technical Symposium in Ft. Lauderdale, Florida, August 25-27, 1997; U.S. Geological Survey Open-File Report 97-385, p. 65-66.
  • Hurley, J.P., D.P. Krabbenhoft, P. Schuster, L.B. Cleckner, M.L. Olson, and G.R. Aiken, 1998, Development of a Conceptual Model of the Everglades Mercury Cycle: Results from Did Smdies, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Krabbenhoft, D.P., Hurley. J.P., Aiken, G.R., Olson, M.L., Dewild, J.F., Cleckner, L.B., Grimshaw, J., Lindberg, S., 1998, The Influence of Photochemical Processes on the Everglades Mercury Cycle., EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Hurley, J.P., 1998, Chlorophyll and Carotenoid Pigments as Indicators of Algal and Phototrophic Bacterial Distributions in The Florida Everglades, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Cleckner, L.B., C.C. Gilmour, J.P. Hurley, and D.P. Krabbenhoft, 1998. Mercury Methylation by Periphyton in the Florida Everglades, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting. Program and Abstracts, May 26-29, Boston, MA.
  • Heyes, A., C.C. Gilmour and J.M. Benoit, 1998, Controls on the Distribution of Methylmercury in the Florida Everglades. EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Harvey, J.W., St. Krupa, R.H. Mooney, P.F. and Schuster, 1998, Are Groundwater and Surface Water in the Northern Everglades Connected By Vertical Hydrologic Fluxes Through Peat?, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Kendall, C., S. Silva, Q.J. Stober, and P. Meyer. 1998, Mapping Spatial Variability in Marsh Redox Conditions in the Florida Everglades Using Biomass Stable Isotopic Compositions, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Schuster P., M.M. Reddy, G.R. Aiken, J.P. Hurley, and D.P. Krabbenhoft, 1998, Diel Sulfide and Dissolved Oxygen Concentration Gradients at Two Sites in the Everglades, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Ravichandran, R., G.R. Aiken, M.M. Reddy, and J.N. Ryan, 1998, Enhanced Dissolution of Cinnabar (Mercuric Sulfide) by Dissolved Organic Matter from the Florida Everglades, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Reddy, M.M. and G.R. Aiken, 1998, Speciation and Fractionation Modeling Studies -Dissolved Organic Carbon (DOC)-Mercury Interaction, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Marvin-DiPasquale, M. and R.S. Oremland, 1998, Bacterial Methylmercury Degradation in Florida Everglades Sediment and Periphyton, EOS. Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Aiken, G.R., and M.M. Reddy, 1998, Dissolved Organic Carbon in the Everglades, Florida, EOS. Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Hoch, A.R., M.M. Reddy, and G.R. Aiken, 1998, Inhibition of Calcite Growth by Natural Organic Material From the Florida Everglades at pH = 8.5 and 25 degrees C, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA..
  • Orem, W.H., H.E. Lerch, M. Corum, A. Boylan, and C. Hedgman. 1998, Phosphorus Geochemistry of the South Florida Wetlands Ecosystem: Sources and Biogeochemical Cycling, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Bates, A.L., W.H. Orem. and J.W. Harvey, 1998, Tracing Sources of Sulfate in the Northern Everglades Using Sulfur Isotopic Compositions, 1998, EOS, Transactions, American Geophysical Union, 1998 Spring Meeting, Program and Abstracts, May 26-29, Boston, MA.
  • Bates A.L., and E.C. Spiker (1994) Speciation and isotopic composition of sedimentary sulfur in the Florida Everglades [abs.]. American Chemical Society National Meeting, Washington, D.C. August 1994.
  • Orem W.H. and H.E. Lerch (1996) Diagenesis and cycling of C,N,P, and S in Everglades peat [abs.]. American Chemical Society National Meeting, Orlando, FL, August 1996.
  • Bates A.L. and E.C. Spiker (1996) Sulfur geochemistry and nutrient enrichment in the Florida Everglades (abs.]. American Chemical Society National Meeting, Orlando, FL, August 1996.
  • Orem W.H., A.L. Bates, A.T. Boylan, M. Corum, C. Hedgman, H.E. Lerch, and R.A. Zielinski, 1997, Biogeochemical cycling of P,S,C, and N in sediments from wetlands of south Florida (abs.]. USGS Program on the South Florida Ecosystem-Proceedings, USGS Open-File Report 97-385, p. 64-65.


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Last updated: 24 April, 2014 @ 01:13 PM (KP)