Collaborative Research: New Constraints on Marine Oxygen Cycling

海洋氧气与海洋环境中有机物质的循环密切相关，因此，其预算对于解决海洋学中的许多悬而未决的问题至关重要。在这项研究中，研究人员将测量三种氧同位素的数量，这些氧同位素可以结合在一起组成溶解在海洋水域中的分子氧气体。当氧与其他物质反应时，根据反应类型的不同，这三种同位素的行为方式可能略有不同；这使得有可能识别导致海洋不同地方发现的氧存在的过程的种类。这些结果有望对氧在各种海洋环境条件下如何与生物、有机物、矿物和其他物质相互作用提供新的见解，对未来海洋生产力和海洋低氧(低氧)带的研究具有重要意义。一名女研究生将亲身体验这些新方法，研究结果将通过社交媒体和视频向公众传播。在这个项目中，研究人员将同时测量氧气的五个稳定同位素变体，即所谓的五重同位素分析，以提供对海洋氧气循环的新限制。他们将使用现场和实验相结合的研究方法，评估五重同位素方法追踪海洋氧气循环的可能性。利用这些新的分析方法，他们将分析圣佩德罗海洋时间序列(SPOT)水柱中O2同位素的深度剖面和暗瓶孵化。这些测量，结合营养剖面和补充的实验室实验，将产生对光合作用、呼吸作用和混合如何影响溶解的海洋O2的同位素组成的第一级了解。

Marine oxygen is strongly linked to the cycling of organic matter in the marine environment, and as such, its budget is central to addressing many of the outstanding questions in oceanography. In this study, researchers will measure the amounts of three isotopes of oxygen that can combine to make up the molecular oxygen gas dissolved in oceanic waters. When oxygen reacts with other substances, the three isotopes can behave in slightly different ways depending on the type of reactions; this makes it possible to identify the kinds of processes that have led to the existence of the oxygen found at different places in the ocean. These results are expected to yield new insights into how oxygen interacts with organisms, organic matter, minerals, and other substances under a variety marine environmental conditions, with important implications for future studies of ocean productivity and hypoxic (low oxygen) zones in the ocean. A female graduate student will gain hands-on experience with these new methods, and results from the research will be disseminated to the general public through social media and a video. In this project, researchers will make simultaneous measurements of five stable isotopic variants of O2, known as quintuple-isotopologue analysis, to provide new constraints on marine oxygen cycling. Using a combined field and experimental study they will evaluate the potential for the quintuple-isotopologue method to trace marine O2 cycling. Utilizing these novel analytical methods, they will analyze depth profiles and dark bottle incubations of O2 isotopologues in the water column at San Pedro Ocean Time Series (SPOT). These measurements, combined with nutrient profiles and complementary laboratory experiments, will yield a first-order understanding of how photosynthesis, respiration, and mixing affect the isotopologue composition of dissolved marine O2.