Riverine Organic Carbon Input into the Ocean in Relation to Late Quaternary Climate Change.

Abstract

Isotopic and geochemical proxies measured in bulk sediment samples have been used to evaluate changes in the riverine organic carbon accumulation of the western equatorial Atlantic. In order to determine the dominant glacial to interglacial controls on the accumulation of terrestrial organic matter discharged by rivers, as weIl as to estimate the amount of terrestrial organic carbon stored in marine sediments off rivers, sediment sampies from the Amazon deep sea fan recovered during "F.S. Meteor" cruise M16-2 and ODP Leg 155 were analysed. Sediments recovered on "F.S. Meteor" cruise M34-4 south of Barbados were further used to trace the fate of terrestrial organic matter discharged by the Amazon and/or Orinoco rivers. Fina11y, a re-estimate of the modern fluviatile terrestrial organic carbon discharge and burial rates is performed on aglobai scale in order to address the question of the fate of terrestrial organic carbon in the ocean. It is intended to enable a better estimate of the portion of terrestrial organic carbon that survives degradation and how much this is relative to the amount of marine organic carbon buried.