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St. Petersburg Coastal and Marine Science Center

Climate and environmental change in the Gulf of Mexico and Caribbean

Research: Paleoclimate Proxy Calibration

Scientists study microfossils preserved in ocean sediments to deduce past environmental conditions (Fig. 1). The types of microfossils and chemistry of microfossil shells contain information on past conditions like ocean temperature. The value of the information from these studies is determined in part by our ability to relate the occurrence of specific microfossils and their shell chemistry to modern conditions.

Researchers from the USGS office in St. Petersburg, Florida are conducting a calibration study in the northern Gulf of Mexico to establish the relationship between microfossil assemblages and their shell chemistry to modern ocean conditions. They deployed a sediment-trap mooring in the northern Gulf of Mexico to measure the flux and chemistry of planktic foraminiferal shells collected in the trap (Fig. 2). Data will be compared with concurrent hydrographic data (Fig. 3). The results will provide better calibration of standard climate proxies, leading to improved interpretation and correlation between marine and continental paleoclimate records.

sediment trap
location and description of sediment trap
Figure 2. Location of sediment-trap mooring
Photograph of planktic foraminifers collected from the sediment trap. Figure 1. Photograph of planktic foraminifers collected from the sediment trap. Magnified 255x. Photo credit: Jessica Spear, USGS.
Total planktic foraminifera flux Weekly flux (tests m-2 day-1) (top panel) of all planktic Foraminifera and the 10 most abundant species/groups during 2008.
Figure 3. Left plot: Total planktic foraminifera flux (tests m-2 day-1) (top panel) and weekly percent abundance of the 10 most abundant species/groups of planktic Foraminifera during 2008. Note the scale changes in the y-axes. [larger version] Right plot: Weekly flux (tests m-2 day-1) (top panel) of all planktic Foraminifera and the 10 most abundant species/groups during 2008. Note the scale changes in the y-axes. [larger version]

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