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Research about Florida

Source-linked reports with geographic coverage including Florida.

At least 1,261 records · Page 70Linked to original sources
USGS2000

Water quality in southern Florida: Florida, 1996-98

Major influences and findings for water quality and biology in southern Florida, including the Everglades, are described and illustrated. Samples were collected to determine total phosphorus, dissolved organic carbon, pesticides, mercury, nitrate, volatile organic carbon compounds, and radon-222. Water-management, agricultural, and land-use practices are discussed. Sixty-three species of fish in 26 families were collected; 43 native species, 10 exotic or nonnative species, and 10 species of marine fish that periodically inhabit canals and rivers were identified.

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USGS2000

Magnitude and distribution of flows into northeastern Florida Bay

Changes in water-management practices have been made to accommodate a large and rapidly growing urban population along the Atlantic Coast and to meet the demand for intensive agricultural activities. These changes have resulted in a highly managed hydrologic system consisting of numerous canals, levees, control structures, and pumping stations that have altered the hydrology of the Everglades and Florida Bay ecosystems. Over the past decade, Florida Bay has experienced sea-grass die-off and algal blooms, which are indicators of ecological change attributed primarily to the increase in salinity and nutrient content of bay waters. Because plans are to restore sheetflow in the Everglades wetlands to its natural state, water managers anticipate a change in the magnitude and timing of freshwater exiting the mainland through the creeks that cut through the embankment or as sheetflow into Florida Bay.

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USGS2000

Interaction between ground water and surface water in the northern Everglades and relation to water budget and mercury cycling; study methods and appendixes

The data presented in this report are products of an investigation that quantified interactions between ground water and surface water at several study sites in the northern Everglades. Goals included identifying the major geologic controls and human alterations that affect interactions between ground water and surface water, and determining how those interactions affect mercury contamination. The primary study area was the 3,815-acre Everglades Nutrient Removal (ENR), a wetland constructed in the early 1990s as a prototype Stormwater Treatment Area (STA), to determine the effectiveness in removing excess nutrients from agricultural drainage. In order to ensure that results from ENR are broadly informative, work was also conducted in Water Conservation Area-2A (WCA-2A), a 105,000-acre basin surrounded by levees. In the past 50 years, WCA-2A has experienced extensive re- engineering of water flow, alterations in the pattern of water-level fluctuations and timing of fire frequency, as well as substantial ecological changes. The most visible ecological alteration is the change in dominance over the past 30 years from a sawgrass wetland to cattail wetland in the northeastern part of WCA-2A. The drastic change in vegetation in WCA-2A resulted at least in part from inputs of excess phosphorus from agricultural drainage. Substantial data collection programs were already in progress in both ENR and WCA- 2A when the present work began. The South Florida Water Management District (SFWMD) constructed the ENR project in 1994 to determine the effectiveness of constructed wetlands for water treatment. Measurements of surface water flow and water quality were made frequently in ENR between 1994 and 1998. Fewer ground water data were collected at ENR, and almost all of it was collected from shallow wells emplaced on perimeter levees. In contrast to the short-term nature of data collection in ENR, hydrologic and chemical data were collected over a much longer period in WCA-2A (since at least the mid- 1970s), but the number of sites and data- collection frequency is much less. Very little prior ground water data were available in WCA-2A. Given the availability of prior information, the present study emphasized the collection of ground water field data, particularly in the interior wetland areas of ENR and WCA- 2A. New wells were emplaced to permit the geologic, hydraulic, and chemical sampling that was needed to characterize interactions between surface water and ground water. In particular, lithology and hydraulic properties of the Surficial aquifer were determined, ground water flow paths and velocities were delineated, hydrologic fluxes between surface water and ground water were measured, and water budgets and surface- subsurface fluxes of mercury were determined. The purpose of this report is to compile under one cover all of the data collected in this investigation. In addition, the report contains a detailed description of the study methods and information about study sites, borehole drilling, well construction, seepage meter installation, and hydraulic and geochemical chemical sampling. Data interpretations are the subject of a companion report.

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USGS2000

Sawgrass density, biomass, and leaf area index: A flume study in support of research on wind sheltering effects in the Florida Everglades

The U.S. Geological Survey is studying the wind sheltering effects of vegetation in the Florida Everglades. In order to test both the flow resistance and wind sheltering effects of sawgrass, uniform dense stands of sawgrass were grown in a tilting flume at Stennis Space Center, Mississippi. In June, 1997, one end of the flume was covered with a wind cowling with a removable top, and a series of experiments were conducted between June, 1997 and July, 1998. During each set of experiments, the sawgrass was sampled for vegetative characteristics, biomass, and leaf area index. The results of the analyses of the vegetation samples are summarized in a series of appendixes.

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USGS2000

A paleoecologic reconstruction of the history of Featherbed Bank, Biscayne National Park, Biscayne Bay, Florida

Using multiple-proxy biological indicators, a paleoecological history of the past 550 years of Featherbed Bank, Biscayne Bay, has been reconstructed from a short (2.26 m) sediment core. Paleoecological changes in ostracode, mollusc, and foraminifer assemblages show that core SEI297-FB-1 can be divided into three distinctly different zones, which together provide evidence for distinct changes in historical environmental conditions at Featherbed Bank. Assemblages from fossil biotic communities within zone 1, representing approximately 1440 to 1550 AD, are characterized by open-marine biota with relatively limited numbers of epiphytic biota. Molluscan faunal indicators suggest the sediment was capable of supporting infaunal organisms and that faunal richness was relatively limited during this time period. A change in the biotic community occurred around 1550 AD and continued until the late 1800's distinguishing zone 2. Fossil biotic indicators from zone 2 show a strong dominance of epiphytic organisms within all of the biotic communities examined. Foraminifers, molluscs, and ostracodes capable of subsisting in salinities slightly lower than normal marine begin to flourish in this time period, and there is a marked decline in infaunal molluscs. Zone 2 assemblages are replaced around 1900 AD by increased numbers of organisms that typify open-marine conditions and a return to decreased epiphytic assemblages, similar to zone 1. Zone 3 assemblages, however, show some strong dissimilarities from zone 1, including limited infaunal molluscs, increased abundances of the ostracode Malzella floridana, and a significant increase in molluscan faunal richness.

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USGS2000

Fate and transport modeling of selected chlorinated organic compounds at Operable Unit 3, U.S. Naval Air Station, Jacksonville, Florida

Ground water contaminated by the chlorinated organic compounds trichloroethene (TCE), cis-dichloroethene (DCE), and vinyl chloride (VC) has been found in the surficial aquifer beneath the Naval Aviation Depot at the U.S. Naval Air Station, Jacksonville, Florida. The affected area is designated Operable Unit 3 (OU3) and covers 134 acres adjacent to the St. Johns River. Site-specific ground-water flow modeling was conducted at OU3 using MODFLOW, and solute-transport modeling was conducted using MT3DMS. Simulations using a low dispersivity value, which resulted in the highest concentration discharging to the St. Johns River, gave the following results. At 60 years traveltime, the highest concentration of TCE associated with the Area C plume had discharged to St. Johns River at a level that exceeded 1x103 micrograms per liter (ug/L). At 100 years traveltime, the highest concentration of TCE associated with the Area D plume had discharged to the river at a level exceeding 3x103 ug/L. At 200 years traveltime, the Area B plume had not begun discharging to the river. Simulations using a first-order decay rate half-life of 13.5 years (the slowest documented) at Area G caused the TCE to degrade before reaching the St. Johns River. If the ratio of the concentrations of TCE to cis-DCE and VC remained relatively constant, these breakdown products would not reach the river. However, the actual breakdown rates of cis-DCE and VC are unknown. Simulations were repeated using average dispersivity values with the following results. At 60 years traveltime, the highest concentration of TCE associated with the Area C plume had discharged to St. Johns River at a level exceeding 4x102 ug/L. At 100 years traveltime, the highest concentration of TCE associated with the Area D plume had discharged to the river at a level exceeding 1x103 ug/L. At 200 years traveltime, the Area B plume had not begun discharging to the river. "Pump and treat" was simulated as a remedial alternative. The concentration of TCE at Area B trended rapidly downward; however, one isolated pocket of TCE remained because of the low-permeability sediments present at this area. The concentration of TCE at Area C trended rapidly downward and was below 1 ug/L in about 16 years. The concentration of TCE at Area D also trended rapidly downward and was below 1 mg/L in about 18 years.

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USGS2000

Interaction between ground water and surface water in Taylor Slough and vicinity, Everglades National Park, South Florida: Study methods and appendixes

The data presented in this report are products of an investigation that quantified interactions between ground water and surface water in Taylor Slough in Everglades National Park. Determining the extent of hydrologic interactions between wetland surface water and ground water in Taylor Slough is important because the balance of freshwater flow in the lower part of the Slough is uncertain. Although freshwater flows through Taylor Slough are quite small in comparison to Shark Slough (the larger of the two major sloughs in Everglades National Park), flows through Taylor Slough are especially important to the ecology of estuarine mangrove embayments of northeastern Florida Bay. Also, wetland and ground- water interactions must be quantified if their role in affecting water quality is to be determined. In order to define basic hydrologic characteristics of the wetland, depth of wetland peat was mapped, and hydraulic conductivity and vertical hydraulic gradients in peat were determined. During specific time periods representing both wet and dry conditions in the area, the distribution of major ions, nutrients, and water stable isotopes throughout the slough were determined. The purpose of chemical measurements was to identify an environmental tracer could be used to quantify ground-water discharge.

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USGS2000

Flow-velocity data collected in the wetlands adjacent to canal C-111 in south Florida during 1997 and 1999

The U.S. Geological Survey (USGS) is working closely with other Federal and State agencies in a comprehensive program to evaluate and restore the south Florida ecosystem. Within the USGS South Florida Ecosystem Program, a project entitled 'Coupling Models for Canal and Wetland Flow/Transport Interaction' is focused on analysis and numerical simulation of flow and potential transport of constituents between canal C-111 and wetlands adjacent to Everglades National Park. In support of this project, comprehensive sets of flow, vegetation, and water-quality data were collected in September 1997 and 1999. The flow-velocity data are compiled, summarized, and tabulated in this report. The flow, vegetation, and water-quality data are available for downloading from the World Wide Web.

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USGS2000

Geochemistry of sulfur in the Florida Everglades: 1994 through 1999

In this report, we present data on the geochemistry of sulfur in sediments and in surface water, groundwater, and rainwater in the Everglades region in south Florida. The results presented here are part of a larger study intended to determine the roles played by the cycling of carbon, nitrogen, phosphorus, and sulfur in the ecology of the south Florida wetlands. The geochemistry of sulfur in the region is particularly important because of its link to the production of toxic methylmercury through processes mediated by sulfate reducing bacteria. Sediment cores were collected from the Everglades Agricultural Area (EAA), Water Conservation Areas (WCAs) 1A and 2A, from Lake Okeechobee, and from Taylor Slough in the southern Everglades. Water collection was more widespread and includes surface water from WCAs 1A, 2A, 3A, 2B, the EAA, Taylor Slough, Lake Okeechobee, and the Kissimmee River. Groundwater was collected from The Everglades Nutrient Removal Area (ENR) and from WCA 2A. Rainwater was collected at two month intervals over a period of one year from the ENR and from WCA 2A. Water was analyzed for sulfate concentration and sulfate sulfur stable isotopic ratio (34S/32S). Sediment cores were analyzed for total sulfur concentration and/or for concentrations of sulfur species (sulfate, organic sulfur, disulfides, and acid volatile sulfides (AVS)) and for their stable sulfur isotopic ratio. Results show a decrease in total sulfur content (1.57 to 0.61 percent dry weight) with depth in two sediment cores collected in WCA 2A, indicating that there has been an increase in total sulfur content in recent times. A sediment core from the center of Lake Okeechobee shows a decrease in total sulfur content with depth (0.28 to 0.08 percent dry weight). A core from the periphery of the lake (South Bay) likewise shows a decrease in total sulfur content with depth (1.00 to 0.69 percent dry weight), however, the overall sulfur content is greater than that near the center at all depths. This suggests input of sulfur in recent times, especially near the lake margins. Sediments show a general decrease in sulfur concentration with depth, probably because of increases in sulfur input to the marshes in recent times. Regional differences in the concentrations and stable isotopic ratios of sulfate sulfur in surface water show that sulfur contamination to the northern Everglades likely originates from canals draining the EAA.

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