Lipid biomarker composition of lower Ganges-Brahmaputra River and Bay of Bengal sediments

GEOC 77

Andrew R. Zimmerman, azimmer@ufl.edu, Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gaineville, FL 32611 and Siddhartha Mitra, smitra@binghamton.edu, Department of Geological Sciences and Environmental Studies, Binghamton University, PO Box 6000, Binghamton, NY 13902-6000.
The Ganges-Brahmaputra River complex (GBR), delivers more sediment to the world's ocean than any other river system and is a globally significant contributor of organic matter (OM) to the ocean. Yet, the sources of this discharged OM from this large and tectonically active drainage basin are not well defined. Using a lipid biomarker approach, we have identified the major biological sources of OM in both solvent-extractable (free and loosely bound) and refractory (released by catalytic hydrogen-pyrolysis) portions of GBR riverine and coastal sediments and suspended particulate materials. While a mixture of algal and terrestrially derived lipid biomarkers were identified in all samples, the majority of lipid compounds found in both loosely bound and refractory OM fractions were likely derived from algal or microbial sources. Mineralogical associations leading to OM preservation in this system will also be discussed.
 

Geochemistry Poster Session
6:00 PM-8:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Geochemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007