[SIO GP Seminars] June 2 Earth Section Seminar: Charlotte Beucher

[Lihini Aluwihare]

Hi all,
Our seminar speaker for Monday, June 2 will be Dr. Charlotte Beucher 
from UCSB. Her talk title is: "Combining d30 Si and d15 N to 
reconstruct nutrients dynamic in the glacial Southern Ocean", and the 
talk abstract is below. Please join us for refreshments at 3:00 in 
Hubbs 4500! The talk will start at 3:15.

Cheers,
-Danny Richter

Abstract
Evaluating the role of the Southern Ocean in regulating 
glacial-interglacial atmospheric CO2 cycles remains a major issue in 
paleoceanography. The study of past nutrient dynamics in the surface 
ocean has recently benefited from new proxies for nutrients use: the 
d30 Si and the diatom-bound d15 N. Silicon and nitrogen isotope 
records from sediment cores from the Antarctic and Subantarctic Zones 
of the Southern Ocean imply a shift from high to low silicon:nitrogen 
uptake ratios in phytoplankton with transition from interglacial to 
glacial periods. Using isotopic mass balance for records of d30 Si 
and d15 N we estimate the nitrate and silicic acid contents of 
Antarctic and Subantarctic surface waters during the Holocene and the 
last glacial maximum (LGM) in the Indian sector of the Southern 
Ocean. We discuss the influence of the Si:N ratio of the exported 
nutrients on low latitude production in the context of the Silicic 
Acid leakage Hypothesis (SALH).


Lihini I Aluwihare
Assistant Professor
Geosciences Research Division
Scripps Institution of Oceanography
La Jolla, CA 92093-0244
Office Phone: (858) 822 4886
Lab Phone: (858) 822 0997
Fax:   (858) 822 3310
http://aluwiharelab.ucsd.edu/
"If not now, then when?"

Please note NEW office address
FedEx and other courier service address
302 Vaughan Hall,
8675 Discovery Way,
La Jolla Ca 92037

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