| This is a cover page. To go to the actual document, click on the title above. |
| The document is in PDF format (376 K). You will need Acrobat Reader to view and print. If you do not have Acrobat Reader, you will need to download the program. |
| Click here to download Adobe Acrobat 3.0, and follow the download and installation instructions provided. After downloading Acrobat, configure your browser to use Acrobat as a helper application. |
A series of short piston cores (<2m) were taken from eleven stations in Florida Bay in May, 1994 by researchers from the U.S. Geological Survey (St. Petersburg, FL, Woods Hole, MA, and Denver, CO) in cooperation with South Florida Water Management District, and the Everglades National Park, and the National Oceanic and Atmospheric Administration (NOAA). Core 6A from Bob Allen Keys (25°1.391" N, 80°39.41" W) penetrated 172 cm of Holocene sediments in 0.6 m of water on a grass covered mud bank, approximately 1.75 miles (2.82 km) east of the water monitoring station on the southern end of the Bob Allen Keys. Core 6A was sampled for particle size, insoluble residue, water content, loss on ignition, Pb210, Ra222, and paleontologic analyses. Here we present the results of the preliminary paleontologic analyses of the biotic components from core #6A.
The Everglades/Florida Bay ecosystem has formed over the last 5000 years at the southern tip of peninsular Florida. Here it has been influenced by Atlantic, Caribbean and Gulf of Mexico waters, and by tropical and subtropical climatic regimes. This location ensures that over time the ecosystem has undergone climatic changes on both a seasonal and long term basis, and that it has been subjected to many major storms. Additionally, in the last century, the hydrologic regime of the region has been altered profoundly through construction of a canal system to control flooding in southern Florida. This system regulates the timing and amount of freshwater flow into Florida Bay. Recently, algal blooms, seagrass, and sponge die-offs, and declining numbers of shellfish, have been reported in Florida Bay; although it has been assumed that these changes have resulted from human alteration of freshwater flow into the bay, this assumption has not been rigorously tested.
The research described here is part of a project designed to examine the history of the Everglades/Florida Bay ecosystem over the last 150 years and to test assumptions of cause and effect. The purpose of the project is two-fold; first, to determine the characteristics of the ecosystem prior to significant human-induced alteration, including the natural range of variation in the ecosystem. This information will establish a baseline for restoration of the system. Second, the project aims to establish the extent, range, and timing of changes to the ecosystem over the last 150 years, and to determine whether these changes correlate with human alteration of the environment, or meteorological patterns, such as precipitation and major storms, or a combination of factors.
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
|
Information for ordering U.S. Geological Survey maps and reports is available by calling 1-888-ASK-USGS. Information for ordering USGS products also is available from the USGS home page on the World Wide Web at URL http://www.usgs.gov/. You can write to
USGS Information Services Fax: 303-202-4695
|
Return to Geologic Mapping and Regional Geologic Studies in the Eastern United States
Return to Open-File Reports
Return to Geologic Information