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Jones, A. A., California Institute of Technology, Pasadena, USA, jonesaa@caltech.edu
Sessions, A. L., California Institute of Technology, Pasadena, USA, als@gps.caltech.edu
Schimmelmann, A. ., Indiana University, Bloomington, USA, aschimme@indiana.edu
Sauer, P. ., Indiana University, Bloomington, USA, pesauer@indiana.edu
Topalov, K. ., Indiana University, Bloomington, USA, topalovk@indiana.edu

USING D/H RATIOS OF BULK FRACTIONS TO CONSTRAIN THE BIOCHEMICAL SOURCES OF PARTICULATE ORGANIC MATTER

As marine particulate organic matter (POM) is transported to the deep ocean, it is chemically altered such that much of it becomes unidentifiable at the molecular level. Because it can compose the large majority of POM in deep waters, understanding the source of this molecularly unidentifiable material is important to building a detailed, mechanistic model of carbon export to sediments. A proxy for the unidentifiable organic matter is the fraction remaining after hydrolysis in 6 M HCl - the acid-insoluble (AI) fraction. Previous investigations into bulk properties of the AI fraction have resulted in conflicting hypotheses on the biochemical source(s) of this material: is it carbohydrate-like, lipid-like, or a transformed mixture of other compounds? Because D/H ratios vary between biochemical classes to a greater extent than other isotopic signatures, the determination of &deltaD in the AI fraction could help constrain its source more precisely. Here we will present a new approach to measuring the D/H ratios of nonexchangeable hydrogen in bulk organic fractions, together with the first measured &deltaD values for the AI fraction from POM.

Poster presentation

Session #:012
Date: 01-27-09
Time: 18:00 - 20:00

Presentation is given by student: Yes