A new study in Marine Micropaleontology proposes a new proxy for winter sea surface temperatures in the past

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Caitlin Reynolds and Julie Richey (Geologists, USGS, St. Petersburg Coastal and Marine Science Center), along with colleagues from University of South Florida, Oregon State University and University of California Davis, published a paper titled "Environmental controls on the geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for paleoceanographic reconstructions."

This study uses foraminifera from the long-running (>10 years) Gulf of Mexico Sediment Trap to investigate the geochemical variations in the calcium carbonate shells of G. truncatulinoides, a species of foraminifera that lives in the surface waters of the Gulf of Mexico exclusively during the winter months. The objective of this study was to verify that this species is living within the surface mixed-layer, and to calibrate its trace metal (Mg/Ca) composition to sea surface water temperature. Ultimately, this study shows that the non-encrusted form of this species can be used to reconstruct winter sea surface temperature in the Atlantic Ocean in the geologic record, allowing scientists to reconstruct changes in seasonal climatic extremes in the past.