CYCLING OF DISSOLVED ORGANIC MATTER IN THE PACIFIC AND ATLANTIC OCEANS USING RADIOCARBON

使用放射性碳循环太平洋和大西洋中的溶解有机物

• 批准号: 1458941
• 负责人: Ellen Druffel
• 金额: $ 64.01万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1458941&HistoricalAwards=false
• 关键词: CYCLING; DISSOLVED; ORGANIC; MATTER; PACIFIC

Dissolved organic carbon is the largest pool of carbon in the ocean, comparable to the total carbon content in the atmosphere. Radiocarbon, a radioactive isotope of carbon, can provide information on the source and timescale of carbon cycling in the environment. Therefore, knowing the carbon isotopic signatures of dissolved organic carbon is important for understanding the biogeochemistry and dynamics of dissolved organic carbon cycling, and is essential for the carbon cycle modeling community. The main objective of this research is to determine the radiocarbon values of dissolved organic carbon in seawater samples from areas in the Pacific and Atlantic Oceans for which little or no data is available to provide much needed, quantitative information on the timescale of dissolved organic carbon cycling in the ocean. Atmospheric carbon will end up in the ocean, and it is critical to improve our understanding of the processes that influence its long-term storage in the deep sea. Results of this research will be made available for use in models that assess present and future concentrations of atmospheric carbon dioxide and its impact on ocean biogeochemistry. This research will also support the work of one graduate student and two undergraduate students and provide hands-on experience that will prepare them for careers as scientists and educators.The average radiocarbon (14C) age of dissolved organic carbon (DOC) in the deep ocean ranges from 4000 to 6500 years. Previous research indicates that DOC 14C in the deep South Pacific is equal to that in the deep North Pacific, suggesting that there is a sink for labile DOC in the subtropical South Pacific, In addition, findings suggest that the content of post-bomb DOC has decreased in Sargasso Sea waters on decadal timescales. These findings indicate that processes other than water mass circulation controls DOC 14C in the deep sea. In this study, a researcher from the University of California, Irvine, will use seawater samples from the Pacific and Atlantic Oceans to test two hypotheses: (1) Radiocarbon of bulk DOC is similar at all latitudes of the deep Pacific basin, and values are higher in the Southern Ocean, suggesting the dual governance of DOC aging, remineralization, and young DOC injection concomitant with deep ocean circulation; (2) Deep DOC radiocarbon values in the North Atlantic Ocean reflect the presence of variable amounts of post-bomb carbon. To test these hypotheses, seawater samples will be analyzed for DOC isotopic signatures in profiles from Pacific and Atlantic Oceans to establish a quantitative understanding of the timescale of DOC cycling in the ocean. This study addresses fundamental gaps in knowledge of the global carbon cycle and the dynamic nature of DOC in the ocean.

溶解的有机碳是海洋中最大的碳池，与大气中的总碳含量相当。放射性碳是一种碳的放射性同位素，可以提供有关环境中碳循环的来源和时间尺度的信息。因此，了解溶解有机碳的碳同位素特征对于理解溶解有机碳循环的生物地球化学和动态非常重要，对于碳循环建模社区至关重要。这项研究的主要目的是确定来自太平洋和大西洋地区的海水样品中溶解有机碳的放射性碳值，这些地区几乎没有或根本没有数据可提供有关溶解有机碳循环的时间表的数量信息。大气碳将最终进入海洋，至关重要的是要提高我们对影响其在深海长期存储的过程的理解。这项研究的结果将用于用于评估当前和未来浓度二氧化碳及其对海洋生物地球化学的影响的模型。这项研究还将支持一名研究生和两名本科生的工作，并提供动手经验，使他们成为科学家和教育工作者的职业。先前的研究表明，南太平洋深太平洋地区的DOC 14C等于北太平洋地区的DOC 14C，这表明南太平洋亚热带的DOC有一个不稳定的DOC，此外，研究结果表明，炸弹后DOC的含量在萨尔加索海水中减少了十年时间表的Sargasso Sea Waters。这些发现表明，除水量循环以外的其他过程中，深海中的DOC 14C。 In this study, a researcher from the University of California, Irvine, will use seawater samples from the Pacific and Atlantic Oceans to test two hypotheses: (1) Radiocarbon of bulk DOC is similar at all latitudes of the deep Pacific basin, and values are higher in the Southern Ocean, suggesting the dual governance of DOC aging, remineralization, and young DOC injection concomitant with deep ocean circulation; （2）北大西洋中深的DOC放射性碳价值反映了存在可变量后炸弹的存在。为了检验这些假设，将对来自太平洋和大西洋的剖面中的DOC同位素特征分析海水样品，以确定对海洋中DOC循环的时间尺度的定量理解。这项研究探讨了全球碳周期知识和DOC在海洋中的动态性质的基本差距。