Collaborative Research: Constraining the sources, ages and alteration of dissolved and particulate lipids in estuarine and coastal organic matter

溶解有机碳（DOC）和颗粒有机碳（POC）的生物化学类别的碳-14研究结果表明，碳水化合物和蛋白质来源于最近固定到有机物质中的二氧化碳（即，而脂质组分是DOC和POC的最高年龄（约103-104岁BP）组分。 脂质部分的年龄较大被认为是由于有机物质来源、停留时间和/或反应性的差异。 然而，需要更多的研究来了解脂质组分的年龄及其对海洋DOC和POC平均年龄的贡献。 出于这个原因，威廉学院和玛丽弗吉尼亚海洋科学研究所的一位科学家以及她来自俄亥俄州州立大学的合作者计划检查这些来源（即，陆源的，海洋的，自然的，人为的），转换，亲脂性有机物的命运跨越陆地-海洋边界的特拉华州湾及其邻近的沿海沃茨。 为了实现他们的目标，研究人员将对不同有机成分的保守与非保守行为进行地球化学评价（即，大部分DOC和POC以及它们的脂质组分）和它们的同位素（δ 14 C和δ 13 C）特征作为盐度的函数。这将提供有关整个河口尺度上每个成分的总体平均输入和汇的信息。 此外，DOC、POC和脂质组分的光化学和微生物反应性将在与河口混合和停留时间相关的时间尺度上的受控培养实验中进行评估。预计这项研究将为亲脂性有机物如何影响河口和沿海沃茨DOC和POC的年龄、反应性和循环提供新的见解。就更广泛的影响而言，这位来自弗吉尼亚海洋科学研究所的威廉和玛丽学院的科学家计划让里约热内卢州大学的研究生参与该研究项目，从而建立美国和巴西科学家之间的合作。 作为该项目的一部分，将支助和培训弗吉尼亚海洋科学研究所威廉和玛丽学院的一名研究生和俄亥俄州州立大学的一名研究生。

Results from carbon-14 studies of biochemical classes of dissolved organic carbon (DOC) and particulate organic carbon (POC) have shown that carbohydrate and protein derive from carbon dioxide that has been recently fixed into organic matter (i.e., modern in age), whereas the lipid fraction is the most highly aged (~103-104 yrs BP) component of both DOC and POC. The older age of the lipid fraction is believed to be due to differences in organic matter sources, residence times, and/or reactivity. However, more studies are needed to understand the age of the lipid fraction and its contribution to the average age of oceanic DOC and POC. For this reason, a scientist from the College of William and Mary Virginia Institute of Marine Science and her collaborator from Ohio State University plan to examine the sources (i.e., terrigenous, marine, natural, anthropogenic), transformations, and fate of lipophilic organic matter across the land-ocean boundary of Delaware Bay and its adjacent coastal waters. To attain their goal, the researcher will carry out a geochemical evaluation of the conservative vs. non-conservative behavior of different organic constituents (i.e., bulk DOC and POC and their lipid components) and their isotopic (delta14C and del13C) signatures as a function of salinity. This will provide information on the overall mean inputs and sinks of each constituent on the scale of the entire estuary. In addition, the photochemical and microbial reactivity of DOC, POC and lipid components will be evaluated in controlled incubation experiments on timescales relevant to estuarine mixing and residence times.It is anticipated that this study will provide new insights on how the lipophilic organic matter contributes to the age, reactivity, and cycling of DOC and POC in estuarine and coastal waters.In terms of the broader impacts, at no cost to the project, the scientist from the College of William and Mary Virginia Institute of Marine Science plans to involve graduate students from the Universidade do Estado do Rio de Janeiro in the research project, thereby building a collaboration between U.S. and Brazilian scientists. One graduate student from the College of William and Mary Virginia Institute of Marine Science and one graduate student from Ohio State University would be supported and trained as part of this project.