Nitrogen Isotope and N2/Ar Biogeochemistry of the Peru Suboxic Zone

世界各大洋的亚氧中间沃茨虽然只占海洋总体积的一小部分（0.1%），但在海洋的氮循环及其生物地球化学和同位素特征中起着至关重要的作用。需要亚氧条件来激活将氮气转化为N2气体的微生物过程。正因为如此，低氧沃茨作为一个主要的水槽，从生物圈中去除氮。位于达特茅斯的马萨诸塞州大学的一名海洋化学家正在与GEOMAR/基尔大学的科学家合作，完成对秘鲁沿海东热带南太平洋的广泛实地研究，这是三个主要的开放海洋低氧区之一。从秘鲁边缘的一系列横断面收集的水样将进行同位素和气体比率分析，以评估以下内容：（1）了解秘鲁亚氧化带对海洋氮和氮同位素收支的净影响以及（2）氮汇强度与边缘沉积物中保存的氮同位素信号之间的关系。 这项研究的结果将使科学界更好地了解海洋氮循环与低氧沃茨之间的关系。至于更广泛的影响，这项研究将完善有关海洋氮循环和气候变化之间过去相互作用的古记录的解释，并有助于全球海洋循环的数值模拟研究。 这项研究代表了美国，德国和秘鲁科学家。 作为该项目的一部分，将支助和培训一名研究生。

The suboxic intermediate waters of the world's oceans, though constituting only a small fraction of total oceanic volume (0.1%), play a vital role in the ocean's nitrogen cycle and its biogeochemical and isotopic signatures. Suboxic conditions are required to activate the microbial processes that convert nitrogen to N2 gas. Because of this, suboxic waters act as a predominant sink, removing nitrogen from the biosphere. An ocean chemist from the University of Massachusetts at Dartmouth is working in collaboration with scientists from GEOMAR/Kiel University to complete an extensive field study of the Eastern Tropical South Pacific Ocean off the coast of Peru, one of the three major open ocean suboxic zones. Water samples, collected from a series of transects off the Peruvian margin, would undergo isotopic and gas ratio analyses to assess the following: (1) insights on the net impact of the Peru suboxic zone on oceanic nitrogen and nitrogen isotope budgets and (2) the relationship between the intensity of the nitrogen sink and the nitrogen isotope signal preserved in margin sediments. Results from this research would provide the science community with a greater understanding of the relationship between the oceanic nitrogen cycle and suboxic waters. As regards broader impacts, this research would refine the interpretation of paleo-records with respect to past interactions between the oceanic nitrogen cycle and climate variability and contribute to numerical modeling studies of the global oceanic cycle. This study represents a collaborative effort between U.S., German, and Peruvian scientists. One graduate student would be supported and trained as part of this project.