Ecosystem management requires knowledge of environmental dynamics. If historical environmental records do not exist, other methods must be employed to obtain this information. A well-known geochemical procedure that supplies this type of data is the use of natural radioactive nuclides to “date” the timing of events. Of the many naturally occurring nuclides, ²¹⁰Pb is the best suited for gauging the timing of episodes in Florida Bay. The age-depth relationships were calculated using the ²¹⁰Pb method for thirty-five sites within Florida Bay. The ages were independently confirmed by comparing the distribution of known concentrations of atmospherically anthropogenic lead recorded in dated cores to similar data in an annually banded coral. Sediments in the western and northern fringe of Florida Bay are accumulating at 0.3 cm/yr, a rate similar to that of sea level rise. In the north-central part of the bay, sediments are accumulating at a faster rate of ~1.0 cm/yr. The highest rate, ~2.0 cm/yr was measured in the northeastern part of the bay on the bank between Pass and Lake Keys. The rapid rate of accumulation in the northeastern part of the bay permits the deciphering of biological and geochemical changes with an accuracy of about two years. In contrast, the intermediate sediment rate in the central part of the bay provides adequate age-depth relationships for deciphering the environmental record of the past 100 years.

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(This abstract was taken from the Greater Everglades Ecosystem Restoration (GEER) Open File Report (PDF, 8.7 MB))

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