Collaborative Research: Tracing the Transformations of Organic Carbon in Marine Sediments using Natural C Isotopes

合作研究：利用天然 C 同位素追踪海洋沉积物中有机碳的转化

• 批准号: 0726819
• 负责人: Tomoko Komada
• 金额: $ 40.27万
• 依托单位: San Francisco State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726819&HistoricalAwards=false
• 关键词: Collaborative; Research; Tracing; Transformations; Organic

Pore-water dissolved organic carbon (DOC) is one of the least characterized pools of organic carbon in the ocean. Thus, its biogeochemical role in the marine carbon cycle remains unclear. Scientists from San Francisco State University and Old Dominion University propose to test the hypothesis that pore water DOC consists not only of material hydrolyzed from labile particulate organic carbon (POC), but also of resistant moieties derived from the solubilization of 14C-depleted, recalcitrant POC. To test their hypothesis, vertical profiles of '13C and '14C signatures of DOC, dissolved inorganic carbon, POC, and carbonates in sediment cores from Santa Monica Basin would be determined. Results from these cores would be analyzed using an isotope mass balance model to determine the component of POC that supplies DOC to pore waters, the component of DOC that is oxidized to dissolved inorganic carbon, and the component that is accumulated in pore water and subsequently released from sediments as a benthic flux. Results of this research would provide new insight into the sources and reactivity of DOC accumulating in, and effluxing from, anoxic continental margin sediments. As regards broader impacts, the outcome of this research would not only impact our understanding of the significance of benthic DOC fluxes on the cycling of DOC in the oceans, but would also further our understanding of the controls on organic carbon mineralization in marine sediments. This research includes funding to support numerous education and training opportunities for graduate and undergraduate students as well as hands on research experiences for high school students through the Project SEED summer programs, an American Chemical Society program created to encourage students from low-income families to pursue a career in the chemical sciences. Findings from this study would also be disseminated beyond the professional scientific community through outreach activities such as teacher workshops and open-house events.

孔隙水溶解有机碳（DOC）是海洋中特征最少的有机碳库之一。因此，其在海洋碳循环中的地球化学作用仍不清楚。来自旧金山弗朗西斯科州立大学和Old自治领大学的科学家们提出了一个假设，即孔隙水DOC不仅由不稳定的颗粒有机碳（POC）水解的物质组成，而且还由来自14 C耗尽的难溶性POC溶解的抗性部分组成。为了验证他们的假设，将确定圣莫尼卡盆地沉积物岩心中DOC、溶解无机碳、POC和碳酸盐的'13 C和' 14 C特征的垂直剖面。将使用同位素质量平衡模型对这些岩心的结果进行分析，以确定向孔隙沃茨提供DOC的POC组分、氧化为溶解无机碳的DOC组分以及在孔隙水中积累并随后作为底栖通量从沉积物中释放的组分。该研究结果将为了解缺氧大陆边缘沉积物中DOC的来源和反应性提供新的思路。至于更广泛的影响，这项研究的结果将不仅影响我们的理解的意义，底栖DOC通量的DOC在海洋中的循环，但也将进一步我们的理解控制海洋沉积物中的有机碳矿化。这项研究包括资助支持研究生和本科生的众多教育和培训机会，以及通过项目种子暑期项目为高中生提供研究经验，这是一个美国化学学会项目，旨在鼓励来自低收入家庭的学生从事化学科学事业。这项研究的结果还将通过教师讲习班和开放日等外联活动在专业科学界以外传播。