Paleoecology and evolutionary response of planktonic foraminifera to the mid-Pliocene Warm Period and Plio-Pleistocene bipolar ice sheet expansion

[摘要] The Pliocene-Recent is associated with many important climatic andpaleoceanographic changes, which have shaped the biotic and abiotic nature ofthe modern world. The closure of the Central American Seaway and thedevelopment and intensification of Northern Hemisphere ice sheets hadprofound global impacts on the latitudinal and vertical structure of theoceans, triggering the extinction and radiation of many marine groups. Inparticular, marine calcifying planktonic foraminifera, which are highlysensitive to water column structure, exhibited a series of extinctions asglobal temperatures fell. By analyzing high-resolution ( ∼  5 kyr) sedimentary records from the Eastern Equatorial Pacific Ocean,complemented with global records from the novel Triton dataset, we documentthe biotic changes in this microfossil group, within which three speciesdisplayed isochronous co-extinction, and species with cold-water affinityincreased in dominance as meridional temperature gradients steepened. Wesuggest that these changes were associated with the terminal stages of theclosure of the Central American Seaway, where following the sustained warmthof the mid-Pliocene Warm Period, bipolar ice sheet expansion initiated aworld in which cold- and deep-dwelling species became increasingly moresuccessful. Such global-scale paleoecological and macroevolutionaryvariations between the Pliocene and the modern icehouse climate wouldsuggest significant deviations from pre-industrial baselines within modernand future marine plankton communities as anthropogenic climate forcingcontinues.

[学科分类] 大气科学