Investigation of Marine Organic Carbon Cycles in the North Pacific and Atlantic Oceans

该项目将完成正在进行的溶解有机碳（DOC）在海洋碳循环中的作用的研究。具体来说，放射性碳（14C）和稳定碳同位素（13C）比值将在两个DOC池中测量：由紫外线（uv）辐射氧化的部分和由高温（HT）燃烧氧化的部分。这些同位素特征，加上总DOC浓度（uv和HT）以及下沉和悬浮颗粒有机碳库的14C、13C和15N特征，将进一步加深我们对海洋中溶解有机质的来源和循环速率的理解。将完成在中太平洋北部环流、马尾藻海和南加州圣莫尼卡盆地收集的海水样本中DOC的同位素特征（14C、13C）和总浓度。将对从亚马逊河羽流和从加利福尼亚州康森普蒂奇外的东北太平洋的一个开放海洋站收集的样本进行额外的测量。后一种测量将与WHOI的E. Druffel和佛罗里达州立大学的J. Bauer联合进行。还计划通过其他氧化技术，如超声波和氯离子的Hg（II）络合配合紫外线照射来证实doc - ht14c的测量。这个项目的目标与美国全球海洋通量联合研究（GOFS）的目标直接相关。

This project will complete ongoing investigations of the role of dissolved organic carbon (DOC) in oceanic carbon cycles. Speci- fically, radiocarbon (14C) and stable carbon isotope (13C) ratios will be measured in two DOC pools: the fraction oxidized by ultraviolet (uv) radiation, and the fraction oxidized by high- temperature (HT) combustion. These isotopic signatures, coupled with total DOC concentrations (uv and HT) and the 14C, 13C and 15N signatures of sinking and suspended particulate organic carbon pools, will further our understanding of the sources and rates of cycling of dissolved organic matter in the oceans. Isotopic signatures (14C, 13C) and total concentrations will be completed for DOC in seawater samples collected in the north central Pacific gyre, the Sargasso Sea, and the Santa Monica Basin off Southern California. Additional measurements will be made on samples to be collected in the Amazon River plume and from an open-ocean station in the northeast Pacific off Point Conception, California. These latter measurements will be in conjunction with E. Druffel, WHOI, and J. Bauer, Florida State University. It is also planned to confirm the DOC-HT 14C measurements by other oxidation techniques, such as ultrasonication and Hg(II) complexation of chloride ion coupled with uv irradiation. The goals of this project are directly related to those of the U.S. Joint Global Ocean Flux Study (GOFS).