Influence of Pre- and Post-depositional Processes on Sedimentary Organic Matter Composition

沉积前后过程对沉积有机质组成的影响

• 批准号: 0526268
• 负责人: Timothy Eglinton
• 金额: $ 59.21万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526268&HistoricalAwards=false
• 关键词: Influence; Pre; Post; depositional; Processes

OCE-0526268The sequestration of organic carbon (OC) in marine sediments is a key component of the global carbon cycle, yet there are still many unanswered questions regarding the exact origin and nature of the organic matter that is buried on the continental margins and in the deep sea. A growing body of evidence indicates that oceanic particulate OC is subject to extensive redistribution by bottom currents, a process that may be particularly prevalent on continental margins. If advective processes are widespread, this finding would have important implications for our understanding of the global carbon cycle and for the interpretation of the paleoceanographic record. In this project, researchers at the Woods Hole Oceanographic Institution will continue their molecular multi-isotopic (especially 14C) investigations of organic matter preserved in contemporary marine sediments. The proposed research builds on several key and somewhat unexpected findings from their prior work that raise new questions and challenge current paradigms on sources and cycling of organic matter in the marine environment. These findings implicate lateral particle transport as a pervasive influence on the amount and type of organic matter that is buried in continental margin sediments, and in general, suggest that pre-depositional processes play an important role in dictating the fate of terrestrial and marine organic carbon in the oceans.The research team seeks to determine whether their preliminary findings are applicable to a broad range of depositional settings and to better characterize and quantify the underlying mechanisms. In particular, they expect to quantify timescales involved in the lateral transport of OC across continental margins, examine the role of benthic nepheloid layers in promoting sediment redistribution and organic matter preservation, and develop a molecular-level understanding of age-reactivity relationships in sedimentary organic matter. In terms of broader impacts, there is reason to expect that findings from this study will bear on models that examine the role of the ocean margins in the sequestration of atmospheric CO2 and forecast the response to climate change. In addition to assessment of the consequences of increasing atmospheric CO2 concentrations, the results of the study may improve current knowledge of the dispersion and fate of other anthropogenic contaminants introduced to the oceans margins. The PI is active in advising postdoctoral, graduate, and undergraduate summer students. The proposed research program will form the foundation for a project to be led by a postdoctoral investigator. The PI also routinely involves undergraduate summer students in his research, and it is anticipated that this activity will continue with respect to the current project. Findings from this study will also be incorporated into the curriculum of the MIT-WHOI Joint Program in Oceanography.

OCE-0526268海洋沉积物中有机碳（OC）的固存是全球碳循环的关键组成部分，但关于埋藏在大陆边缘和深海中的有机物质的确切来源和性质仍有许多未解之谜。 越来越多的证据表明，海洋颗粒有机碳受到底层洋流的广泛重新分配，这一过程在大陆边缘可能特别普遍。 如果平流过程是广泛的，这一发现将对我们理解全球碳循环和解释古海洋学记录具有重要意义。在这个项目中，伍兹霍尔海洋研究所的研究人员将继续对保存在当代海洋沉积物中的有机物进行分子多同位素（特别是14 C）调查。 拟议的研究建立在他们先前工作的几个关键和有点意想不到的发现的基础上，这些发现提出了新的问题，并挑战了海洋环境中有机物质来源和循环的现有范式。 这些发现表明，横向颗粒迁移对埋藏在大陆边缘沉积物中的有机质的数量和类型具有普遍影响，一般来说，这表明，沉积过程在决定海洋中陆地和海洋有机碳的命运方面起着重要作用。研究小组试图确定他们的初步研究结果是否适用于广泛的沉积环境，更好地描述和量化潜在机制。 特别是，他们希望量化OC跨大陆边缘横向运输所涉及的时间尺度，研究底栖云状层在促进沉积物再分布和有机质保存方面的作用，并在分子水平上了解沉积有机质中的年龄-反应性关系。就更广泛的影响而言，有理由预期，这项研究的结果将对研究海洋边缘在大气二氧化碳固存中的作用和预测对气候变化的反应的模型产生影响。 除了评估大气中二氧化碳浓度增加的后果外，这项研究的结果可能会改善目前对海洋边缘其他人为污染物的扩散和归宿的了解。 PI积极为博士后，研究生和本科暑期学生提供咨询。 拟议的研究计划将形成一个项目的基础，由博士后研究人员领导。 PI还定期让本科暑期学生参与其研究，预计这项活动将继续进行。 这项研究的结果也将纳入麻省理工学院-世界卫生组织海洋学联合方案的课程。