Announcement of the posting of the Aquatic Cycling of Mercury in the Everglades (ACME) database on the USGS South Florida Information Access (SOFIA) web page
The U.S. Geological Survey (USGS) and the Florida Department of Environmental Protection (FDEP) are pleased to announce the completion and posting of the Aquatic Cycling of Mercury in the Everglades (ACME) database available at the USGS South Florida Information Access (SOFIA) web page: http://sofia.usgs.gov/exchange/acme/introduction.php
This database comprises data from all ACME researchers, now sited in one central data set (presently, 61 parameters and 281 sites) to promote its use by interested stakeholders.
This website will allow download of biogeochemical field data from the ACME study, a long-term multi-investigator research study designed to help comprehend the biogeochemical controls on methylmercury production in the Florida Everglades. Data are available in tab-delimited or CSV (comma-separated values) text format, which may then be imported into Excel, or most spreadsheet or database programs. Data may be selected by station, water quality parameter and date.
In the late-1980' s, the State of Florida noted that methylmercury (MeHg) levels in Everglades fish were elevated, prompting more sampling. The Everglades is now recognized to have among the highest mercury levels in fish in Florida; the Everglades National Park (ENP) currently has mercury levels in fish that are similar to those at other known mercury hot spots in the United States. Such mercury levels represent risk to anglers and wildlife from consuming Everglades fish. Elevated fish mercury values are in part due to the high atmospheric deposition rate of inorganic mercury to south Florida as a consequence of its meteorology, latitude and atmospheric chemistry.
The Aquatic Cycling of Mercury in the Everglades (ACME) study was designed to evaluate the processes that lead to excessive net MeHg production and bioaccumulation in parts of the Everglades. MeHg is the dominant form of mercury that accumulates in food webs. Between 1995 and 2008, the ACME project examined in detail the biogeochemical parameters that influence MeHg production in the Florida Everglades. The interdisciplinary ACME team studied mercury cycling in the Everglades through a process-based, biogeochemical lens. In the Everglades, as in most other ecosystems, inorganic mercury is transformed into methylmercury primarily by the action of anaerobic bacteria in surficial sediments and soils.
The study has built on two decades of research on mercury cycling by the study team from USGS, the Smithsonian Environmental Research Center, and other institutions. The biogeochemical parameters examined focus on those that impact net MeHg production, and include sulfur, carbon and nutrients. The study examined inorganic mercury and MeHg concentrations, and associated biogeochemical parameters in surface waters, soils, periphyton, emergent plants and biota.
The core ACME project team is comprised of:
- David Krabbenhoft, Ph.D., USGS, Middleton, WI
- William Orem, Ph.D., USGS, Reston, VA
- George Aiken, Ph.D., USGS, Boulder, CO
- Cynthia Gilmour, Ph.D., Smithsonian Environmental Research Center, Edgewater, MD
ACME STUDY DESIGN
The ACME field study entailed a detailed assessment, through time, of the biogeochemistry of a core set of study sites across the full length of the Everglades ecosystem. These 10 core sites include locations in each of the main components of the system; from the Loxahatchee National Wildlife Refuge in the north to Everglades National Park in the south (see website). The core study sites are LOX (in Loxahatchee National Wildlife Refuge), ENR103 (in the former Everglades Nutrient Removal project site, now STA1W), WCA2AF1, WCA2AU3 (in Water Conservation Area 2A), WCA2BS (Water Conservation Area 2B), WCA3A33, WCA3A15 and WCA3ATH (in Water Conservation Area 3A), ENPTS7 and ENPTS9 (ENP). From 1995 - 1998, these sites were visited 2-4 times per year; most sites were subsequently visited less frequently.
Many additional marsh, canal, mangrove and Florida Bay sites across the Greater Everglades Ecosystem, including the Stormwater Treatment Areas, were also sampled opportunistically by the ACME team and are included in this data base.
The data set includes information on inorganic mercury and MeHg concentrations in surface water, soil interstitial waters (pore waters), and soils. A wide variety of additional soil and water chemistry data were also collected, as well as some measurements of microbial activity, specifically sulfate reduction rates and inorganic mercury methylation rate constants. ACME parameters were chosen with a focus on sulfur cycling and organic matter characterization.
This data set can be used to provide information on the relationships between MeHg production and biogeochemical variables, like nutrients, sulfate, sulfide, and dissolved organic matter.
The ACME data set highlights the large gradients in sulfur, MeHg and dissolved organic matter across the Greater Everglades Ecosystem, driven in part by agricultural drainage and water management practices.
ACME found that sulfate loading to the Everglades increases microbial sulfate reduction in soils, leading to more reducing conditions, greater cycling of nutrients in soils, production of toxic sulfide, and enhanced MeHg production and bioaccumulation in some parts of the Everglades ecosystem.
The study also showed that sulfate loading and peat degradation are linked processes that lead to increased concentrations and reactivity of dissolved organic matter in the impacted areas. In turn, this highly reactive dissolved organic matter also enhances MeHg production.
Components of the ACME study data have been published in a variety of papers in the primary literature and in reports to the FDEP, South Florida Water Management District (SFWMD), and the USGS. Updates on the study appear regularly in South Florida Environmental Reports (SFER) http://www.sfwmd.gov/portal/page/portal/xweb%20about%20us/agency%20reports .
G. Ronnie Best, PhD, PWS
Coordinator, Greater Everglades Priority Ecosystems Science
United States Geological Survey
Physical Location: Florida Atlantic University - Davie West
3233 College Ave., Room 319
Mail: 3205 College Ave., Ft. Lauderdale FL, 33314-7719
Phone: 954.236.1228 | Cell: 954.658.4676
Donald M. Axelrad, PhD
Florida Department of Environmental Protection
Division of Environmental Assessment and Restoration
2600 Blair Stone Road, MS-6511
Tallahassee, FL 32399-2400
Phone: 850.245.8072 | Cell: 850.443.4626