HR: 17:15h
AN: PP14A-06    [Abstracts]
TI: Coccolithophorid Productivity Response to Paleocene-Eocene Thermal Maximum
AU: * Stoll, H M
EM: hstoll@williams.edu
AF: Geoscience Dept., Williams College, 947 Main St, Williamstown, MA 01267 United States
AU: Shimizu, N
EM: nshimizu@whoi.edu
AF: Dept. Geology and Geophysics, Woods Hole Oceanographic Inst., Woods Hole, MA 02543 United States
AU: Arevalos, A
EM: 05ala@williams.edu
AF: Geoscience Dept., Williams College, 947 Main St, Williamstown, MA 01267 United States
AU: Theroux, S
EM: 05smt@williams.edu
AF: Geoscience Dept., Williams College, 947 Main St, Williamstown, MA 01267 United States
AB: The response of marine plankton to the Paleocene-Eocene Thermal Maximum may have influenced the rate of uptake of greenhouse gases and recovery of the climate but indicators of marine productivity in the open ocean are sparse and have yielded conflicting results at some sites. Here we report on the productivity response of coccolithophorids during the PETM at sites from the Southern Ocean, Tropical Pacific, and Tropical Atlantic. A novel technique for picking individual coccoliths for analysis using secondary ion mass spectrometery (SIMS) allows us to apply the coccolith Sr/Ca productivity proxy to individual genera and avoid biases from changing species assemblages and noncoccolith carbonate in sediments. In the Southern Ocean site, Chiasmolithus experiences a brief surge in productivity in the first thousand years following the event onset, Zygrhablithus experiences an increase in productivity beginning about 20,000 years following the event onset and lasting about 50,000 years. Toweius, the dominant genera, experiences increased productivity beginning about 20,000 years following the event onset and lasting about 100,000 years and likely contributing to the high carbonate accumulation rates at this site during the carbon isotope recovery. Discoaster shows a slight decrease in productivity. In the Equatorial Pacific Site, Toweius experiences a dramatic decline in productivity after the event onset, and recovery to pre-event levels about 50,000 years later. Discoaster shows a slight increase in productivity during the PETM. In the Equatorial Atlantic site, Toweius shows a slight decrease in productivity during the PETM whereas Coccolithus is unaffected. Consequently, while published Os isotopic data are inferred to indicate increased global average weathering rates, the largest effect of such an increase may have been in higher latitude areas which were previously weathering-limited. Hence, the effect of nutrient fertilization may have been confined to these regions.
DE: 4267 Paleoceanography
DE: 1065 Trace elements (3670)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting