Project Lead: Thomas M. Cronin
Knowing the historical and pre-historical environmental conditions for a coastal ecosystems such as Tampa Bay can be very important when determining the effects of climate variability or sea-level change, conducting habitat restoration, or evaluating the health of ecosystems. Sediment cores are a common method for determining pre-historical conditions and the impact of human activity in the bay and its watershed during the historical period.
The USGS, in cooperation with Eckerd College and the University of South Florida, have collected sediment cores as part of the Tampa Bay Study. The cores are collected from a boat using either a vibracore or push-core system and then brought back into the lab for analysis.
Many variables are studied and measured in the sediment, among them grain-size (useful in analysis of turbidity and water clarity), pollen grains (indicator of climate and land-use), benthic microfossils (indicators of salinity and water quality, and a variety of geochemical proxies (indicators of salinity, water quality, pollution etc). The temporal patterns obtained from these proxies, when interpreted in light of an age model developed from radiocarbon and other dating methods, tell researchers and managers about the environmental health of the bay and how to restore the bay to more pristine conditions.
Sediment grain-size and other variables are collected at depth, which can then be interpreted to a temporal scale using a carbon-dating process.
Read: Research Vessel Marion Dufresne Cores Tampa Bay, Florida (USGS Soundwaves article by Terry Edgar (USGS), September, 2002.)