In this proposal, Prahl advances the hypothesis that the organic carbon accumulating in the slope region is highly degraded and derives from the erosion of soils. Further organic geochemical study of sediments collected along an offshore transect extending from the midshelf and down the slope to the opening of Cascadia Basin are proposed to test this hypothesis. Results from these analyses will provide answers to two fundamental questions: 1) Do sediments from the slope region, in general, contain a 20-30% terrestrial component of total organic carbon or does the terrestrial component continuously decrease with further distance down the slope? 2) Is there geochemical evidence preserved in sediment cores from this coastal region that the composition of bulk organic carbon discharged by the Columbia River has changed qualitatively over the past 50-100 years.
