U.S. Department of the Interior
U.S. Geological Survey
OFR-98-76

This report presents data for samples of periphyton and water collected in 1995 and 1996 from Water Conservation Areas, the Big Cypress National Preserve, and the Everglades National Park in south Florida. Periphyton samples were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Water-column samples collected on the same dates as the periphyton samples were analyzed for concentrations of major ions.

Figure 1. Location of study area and sampling sites for periphyton in South Florida. [larger image]

Periphyton is attached algae; it is ubiquitous in the south Florida ecosystem. Periphyton found in south Florida can be characterized as a plant assemblage, including microbial communities of algae and cyanobacteria, that live on submerged aquatic vegetation (Browder and others, 1997). Algae are known to concentrate heavy metals from surrounding waters (Huntsman and Sunda, 1980; Xue and others, 1988; Crist and others, 1994) and can be indicators of metals in the environment. Algal substrates can be the source of organometallic compounds (Simon and Morrison, 1991). Because of the sorption behavior of algae with respect to heavy metals, periphyton of the south Florida marshes was examined for mercury accumulation.

This report provides a compilation of data collected by the U.S. Geological Survey (USGS) from March 1995 through December 1996 in support of the Aquatic Cycling of Mercury in the Everglades Project of the USGS South Florida Ecosystem Program. The report includes water column chemistry for samples collected in March, July and December 1995 and June and December 1996. It also includes results of analyses of (1) whole periphyton samples representing grab samples, (2) whole periphyton samples with replicates to evaluate homogeneity, and (3) periphyton mat samples that were sectioned before analysis. More than 150 samples of periphyton were analyzed. Methods and techniques for sample analysis are discussed.

The study area is located in the area of Florida south of Lake Okeechobee (Figure 1). It includes Water Conservation Areas (WCA) 2A, 2B, 3A, and 3B. Also included are sites in the Big Cypress National Preserve and Everglades National Park.

The South Florida Ecosystem Program provides funding for the Aquatic Cycling of Mercury in the Everglades Project. The assistance of Benjamin McPherson and Kim Haag, South Florida National Water Quality Assessment Program, USGS, Tampa, FL, and Peter S. Rawlik, South Florida Water Management District, West Palm Beach, FL, in the collection of samples is greatly appreciated.

Related information:

SOFIA Projects:

Cycling and Speciation of Mercury in the Food Chain of South Florida

Aquatic Cycling of Mercury in the Everglades