Organic geochemical characterization of sediments from the continental shelf south of New England as an indicator of shelf edge exchange

Abstract

Organic geochemical determinations of total organic carbon (TOC), lignin and extractable alkanes, polycyclic aromatic hydrocarbons, fatty acids, alcohols, sterols, amino acids and carbohydrates have been performed on six cores collected during the SEEP—I cruises from the continental margin off southern New England. Our objective was to study the areal distribution and sources of the various classes of organic compounds which would enable us to understand their transport from the shelf through slope to the rise. Measured components in the cores in the mud patch region are homogeneously distributed throughout their length, indicating either bioturbation or low rate of mineralization in the sediments. The identifiable organic matter decreases from the shelf through slope to rise. A generally linear correlation is observed between TOC and most of the organic compound classes studied. Assuming that organic matter is transported by resuspension of sediment or along the sediment floor, we estimate that nearly 40–50% of the organic matter is exported to the slope from the shelf.