Werne, J. P. Northwestern University, josef@earth.nwu.edu
Hollander, D. P. Northwestern University, david@earth.nwu.edu

 
COMPOUND-SPECIFIC ISOTOPE RECORDS OF PLANKTONIC ECOSYSTEM VARIABILITY IN THE CARIACO BASIN, YOUNGER DRYAS TO PRESENT
 
A high-resolution organic-isotopic study has indicated that the planktonic ecosystem in the Cariaco Basin, Venezuela, has undergone significant variation over the past 12.6 ka. These changes are directly linked to documented local oceanographic and global climate fluctuations associated with the transition from the Younger Dryas cold period to the Holocene conditions. Accumulation rates of individual biomarker compounds indicate that the dominant primary producer in the phytoplanktonic assemblage has changed from diatoms during the Younger Dryas to coccolithophorids during the Holocene. Compound-specific isotopic analyses have indicated further changes in the planktonic community structure. Zooplankton biomarker isotopic values track those of diatom biomarkers, suggesting that diatoms are the primary food source for zooplankton in the Cariaco Basin throughout the period from the Younger Dryas to present. Isotopic shifts of approximately 10 have been identified in several biomarkers, while others shift by less than 3. The differences in isotopic trends of biomarkers indicative of diatoms, dinoflagellates, coccolithophorids and zooplankton are interpreted in the context of variability in habitat (e.g., depth in the water column, season of production), external oceanographic forcings, and metabolic differences.
 
Day: Tuesday, Feb. 2
Time: 08:30 - 08:45am
Location: Eldorado Hotel
 
Code: SS32TU0830E