Principal Investigator: Dr. Terry A. Nelsen
Collaborating scientist(s):
Dr. H. Wanless - U. Miami
Dr. P. Blackwelder, Dr. T. Hood, C. Alvarez-Zarikian, Dr. P. Swart - U. Miami/RSMAS
Dr. J. Trefry, Woo-Jun Kang, Dr. Simone Metz - Florida Tech
Dr. L. Tedesco, Mike O'Neal - U. Indiana/Purdue
Jennifer Garte - NOAA/AOML
Objective: This program is a combined research effort of scientists at AOML and three academic institutions that is designed to carry out a retrospective analysis of sediments from the South Florida Everglades/Florida Bay region in order to identify natural and anthropogenic changes recorded in this ecosystem over time.
Rationale: Until the building of the water diversion canals and roads, in the early 1900s, freshwater runoff across the South Florida peninsula, and into the lower Everglades/Florida Bay ecosystem, was at volumes considerably in excess (+59%) of today's levels. Perturbations such as these tend to stress natural environments and their ecosystems. Current documented ecological problems, within Florida Bay, may be the result of such perturbations.
Method: The proposed program combines a large variety of physical, chemical, and biological measurements including stratigraphy, mineralogy, geochronology, biostratigraphy, selected heavy-metals, isotopes, and pollen analyses.
Accomplishment: Despite the fact that this program has been funded just one year, our initial studies have documented anthropogenic influences within the portion of the coastal zone that forms the transition between the Everglades and Florida Bay. Specifically, preliminary results of a three core sequence from the Everglades' freshwater zone coastward revealed a elevated landward Hg burden within these sediments (>150 ppb) that declined seaward (~10 ppb). Moverover, age dating of strata via geochronoloy shows an increase above the 1940 time horizon. Ongoing work helps to resolve the causes for this increase (figure). Changes in biocommunity structure are also being evaluated for both anthropogenic and natural causes as seen in the following (figure).
Key reference:
Wanless, H., T. Nelsen, L. Tedesco, J. Trefry, P. Blackwelder, and J. Risi, (1995), Documenting the styles of sedimentation and contained historical sedimentary record in shallow marine environments in and adjacent to Florida Bay, South Florida. Abstract for Florida Bay Science Conference: A Report by Principal Investigators.

Zetwo, M. editor, (1996), The Sediment Record as a Monitor of Natural and Anthropogenic Changes in the Lower Everglades/Florida Bay Ecosystem, NOAA/AOML/OCD, Progress Report.

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