Estimating Piacenzian Planktonic Foraminiferal Sea Surface Temperature Preferences

Abstract:

Stationarity of environmental preferences is a primary assumption required for any paleoenvironmental reconstruction using fossil materials based upon calibration to modern organisms. Confidence in this assumption decreases the further back in time one goes. Specifically in Pliocene studies, the validity of the assumption that species temperature tolerances have not changed over time has been challenged. We use paired sea surface temperature (SST) and faunal assemblage data to estimate the temperature preferences of four common Pliocene taxa: Dentoglobigerina altispira, Globorotalia puncticulata, Neogloboquadrina incompta, and N. atlantica. Based upon available data, the extinct species D. altispira is confirmed as a tropical taxon with temperature preferences similar to extant Globigerinoides sacculifer. Globorotalia puncticulata has temperature preferences similar to its evolutionary descendant, Gl. inflata, and the extant species N. incompta has similar preferences today as it did in the Pliocene. The extinct Neogloboquadrina atlantica, like D. altispira, has no present day descendent, but abundances in Pliocene samples suggest that it represents a cold-end member of the genus. With temperature preferences established for these four common Pliocene taxa, we demonstrate greater qualitative confidence in existing paleoenvironmental estimates based upon calibration to modern species.