Development and application of a high sensitivity, ultra low volume method to measure biomarkers of terrigenous organic matter in the open ocean

长期以来，海洋学家一直对海洋中陆源或陆源有机质的分布和命运感兴趣，但随着对海洋和全球碳循环研究的加强，这种兴趣大大增加了。木质素是一种主要的结构聚合物，仅存在于维管植物中，使木质素成为输入海洋环境的陆源有机物的独特示踪剂。目前用于分析木质素的分析工具，将其分解成一系列可识别的酚类化合物，复杂，耗时，需要10到30升水。鉴于这些限制，木质素酚类作为海洋陆生有机碳示踪剂的应用一直很少。通过这个项目，研究人员的目标是重新设计现有的化学方法，以及改进的仪器检测，使用不到200毫升的样品，灵敏度甚至提高3倍。为科学界提供新的方法来灵敏地追踪陆源有机碳的标记，将使人们更清楚地了解陆地和海洋储层之间和内部的有机质通量，并有可能将木质素酚作为一种强大的海洋示踪剂。该项目将支持下一代科学家的发展，包括一名早期职业研究者，以及研究生和本科生。木质素酚测量已被用于研究全球海洋中陆源溶解有机碳（tDOC）的一般分布模式和分解机制。海洋盆地间tDOC的分布格局与全球河流向海洋盆地的排放格局基本一致。然而，由于现有木质素酚法的困难和局限性，需要大规模推广和更全面地解决木质素作为tDOC示踪剂的分布问题受到了阻碍。该项目的主要目标是：(1)开发在开放海水中以高灵敏度测量超低体积溶解木质素的方法；(2)应用新方法研究北冰洋欧亚盆地的陆源tDOC加工和运输，西伯利亚大河将大部分tDOC输送到大陆架地区。这项研究的结果将有助于评估木质素酚作为强大的海洋示踪剂，有助于研究北冰洋的物理混合，并有可能提高我们对海洋中陆源有机碳的命运和去除的理解。解决第二个目标将为北冰洋中木质素和tDOC的衰减常数提供良好的约束，并提供关于盐斜形成的新信息。tDOC预算、淡水预算、环流和大气模式的整合将最终提高对北冰洋生物地球化学循环及其在全球气候中的作用的认识。

Development and application of a high sensitivity, ultra low volume method to measure biomarkers of terrigenous organic matter in the open oceanKarl KaiserID: 1536506The distribution and fate of land-derived, or terrigenous, organic matter in the ocean has long been of interest to oceanographers, but that interest has grown considerably as research on the marine and global carbon cycle intensifies. Lignin is a major structural polymer found only in vascular plants, making lignin a unique tracer of terrigenous organic matter input to the marine environment. The current analytical tool for analyzing lignin, breaking it into a suite of identifiable phenolic compounds, is complex, time consuming and requires 10 to 30 liters of water. Given these limitations, applications of lignin phenols as tracers of terrestrial organic carbon in the ocean have been sparse. Through this project, the researchers aim to redesign existing chemical methodology together with modified instrumental detection for even 3 times greater sensitivity using a sample of less than 200 milliliters. Outfitting the scientific community with new methodology to sensitively trace this marker of terrigenous organic carbon will provide a clearer understanding of organic matter fluxes between and within terrestrial and oceanic reservoirs, and potentially establish lignin phenols as a robust oceanographic tracer. This project will support the development of the next generation of scientists, including an early career investigator, and graduate and undergraduate students.Lignin phenol measurements have been used to study general distribution patterns and mechanisms of decomposition of terrigenous dissolved organic carbon (tDOC) in the global ocean. The distribution pattern of tDOC among ocean basins is generally consistent with the global pattern of riverine discharge to the ocean basins. However, large scale generalizations required and more fully resolved distributions of lignin as a tracer of tDOC are hampered by the difficulties and limitations associated with the present lignin phenol method. The main objectives of this project are to (1) develop methodology for measuring dissolved lignin in ultra-low volumes at high sensitivity in open ocean seawater and (2) apply the new method to study terrigenous tDOC processing and transport in the Eurasian Basin of the Arctic Ocean, where large Siberian rivers deliver the bulk of tDOC to the shelf areas. Results from this research will help evaluate lignin phenols as robust oceanographic tracers, useful to study physical mixing in the Arctic Ocean and potentially improve our understanding of the fate and removal of terrigenous organic carbon in the oceans. Addressing the second objective would provide well-constrained decay constants for lignin and tDOC in the Arctic Ocean and provide novel information on halocline formation. Integration of tDOC budgets, freshwater budgets, and circulation and atmospheric patterns will ultimately improve understanding of biogeochemical cycles in the Arctic Ocean and its role in global climate.