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: 0727179
• 负责人: David Burdige
• 金额: $ 12.22万
• 依托单位: Old Dominion University Research Foundation
• 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 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727179&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 '4C 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）是海洋中最不具特征的有机碳库之一。因此，其在海洋碳循环中的生物地球化学作用尚不清楚。来自旧金山州立大学和老多明尼安大学的科学家们提出要验证这样的假设，即孔隙水中的DOC不仅由可降解颗粒有机碳（POC）水解的物质组成，而且还包括来自14c耗尽的难降解POC增溶的抗性部分。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“13C”和“4C”特征的垂直剖面。这些岩心的结果将使用同位素质量平衡模型进行分析，以确定向孔隙水提供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生物通量从沉积物中释放的组分。本研究结果将对缺氧大陆边缘沉积物中DOC的来源和反应性提供新的认识。就更广泛的影响而言，本研究的结果不仅会影响我们对底栖生物DOC通量对海洋DOC循环意义的理解，而且还会进一步加深我们对海洋沉积物中有机碳矿化控制的理解。这项研究包括为研究生和本科生提供大量的教育和培训机会，以及通过SEED项目暑期项目为高中生提供实践研究经验。SEED项目是美国化学会的一个项目，旨在鼓励低收入家庭的学生从事化学科学方面的职业。这项研究的结果还将通过教师讲习班和开放活动等外联活动传播到专业科学界以外。