Transfer of organic carbon through marine water columns to sediments - insights from stable and radiocarbon isotopes of lipid biomarkers

TitleTransfer of organic carbon through marine water columns to sediments - insights from stable and radiocarbon isotopes of lipid biomarkers
Publication TypeJournal Article
Year of Publication2014
AuthorsWakeham S.G, McNichol A.P
JournalBiogeosciences
Volume11
Issue23
Pagination6895-6914
ISSN1726-4170
Abstract

Compound-specific C-13 and C-14 compositions of diverse lipid biomarkers (fatty acids, alkenones, hydrocarbons, sterols and fatty alcohols) were measured in sinking particulate matter collected in sediment traps and from underlying surface sediments in the Black Sea, the Arabian Sea and the Ross Sea. The goal was to develop a multiparameter approach to constrain relative inputs of organic carbon (OC) from marine biomass, terrigenous vascular-plant and relict-kerogen sources. Using an isotope mass balance, we calculate that marine biomass in sediment trap material from the Black Sea and Arabian Sea accounted for 66-100% of OC, with lower terrigenous (3-8 %) and relict (4-16 %) contributions. Marine biomass in sediments constituted lower proportions of OC (66-90 %), with consequentially higher proportions of terrigenous and relict carbon (3-17 and 713 %, respectively). Ross Sea data were insufficient to allow similar mass balance calculations. These results suggest that, whereas particulate organic carbon is overwhelmingly marine in origin, pre-aged allochthonous terrigenous and relict OC become proportionally more important in sediments, consistent with pre-aged OC being better preserved during vertical transport to and burial at the seafloor than the upper-ocean-derived marine OC.

DOI10.5194/bg-11-6895-2014