Assessment of the Sources and Quality of Organic Carbon Preserved in Sediments from the Southern Washington Continental Shelf and Slope

在这一提议中，Prahl提出了一个假设，即斜坡区有机碳的积累是高度退化的，来源于土壤的侵蚀。为了验证这一假设，我们提出了进一步的有机地球化学研究，对从中陆架延伸到卡斯卡迪亚盆地开口的海岸样带收集的沉积物进行研究。这些分析的结果将提供两个基本问题的答案：1)一般来说，斜坡地区的沉积物含有总有机碳的20-30%的陆地成分，还是陆地成分随着斜坡的进一步下降而不断减少？2)该沿海地区沉积物岩心中是否有地球化学证据表明，在过去的50-100年里，哥伦比亚河排放的大块有机碳的组成发生了质的变化？

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.