Collaborative Research: GEOTRACES Arctic Ocean section-Constraining Nitrogen Cycling in the western Arctic Ocean.

合作研究：GEOTRACES 北冰洋部分 - 限制北冰洋西部的氮循环。

• 批准号: 1434417
• 负责人: Mark Altabet
• 金额: $ 17.46万
• 依托单位: University of Massachusetts, Dartmouth
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434417&HistoricalAwards=false
• 关键词: Collaborative; Research; GEOTRACES; Arctic; Ocean

In this project, a group of investigators from the University of Connecticut, the University of Massachusetts-Dartmouth, and Brown University will participate in the 2015 U.S. GEOTRACES Arctic expedition to determine the biogeochemistry of nitrogen in the region. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. Nitrogen is one of the two major nutrients required universally by plankton in the ocean, and this study in the Arctic Ocean will increase our understanding of the ocean?s ecology, productivity, and carbon cycle. This study will also provide training for graduate and undergraduate students, and results will be shared through public outreach events.The state of knowledge of Arctic nitrogen (N) biogeochemistry remains cursory as compared to that in other ocean basins despite the fact that understanding Arctic Ocean nitrogen cycling is central to understanding its global biogeochemistry. For one, benthic nitrogen loss on Arctic continental shelves may represent a globally significant sink of oceanic fixed nitrogen. Second, benthic nitrogen loss on the Arctic continental shelf and slope reduces the ratio of nitrate to phosphate substantially below the mean requirements of phytoplankton nitrogen, consequently limiting primary production at the ice-free surface of the western Arctic Ocean. In light of the rapid changes in Arctic climatology, the characterization of its biogeochemistry and establishment of a baseline from which to monitor future changes is critical. Researchers will use the stable N isotope (15N/14N) ratio in nitrate, nitrite, ammonium, and nitrogen gas determined for a suite of dissolved, particulate, atmospheric, snow, and sea-ice samples to better constrain the spatial and temporal variability of biological nitrogen transformations in the Arctic. Results from this study will provide a first order understanding of the contribution of water masses to the regional nitrogen budget, identify regional nitrogen sources and sinks, and diagnose important biological nitrogen transformations that occur on the Chukchi shelf, and in the central basins.

在该项目中，来自康涅狄格大学，马萨诸塞州达特茅斯大学和布朗大学的一组研究人员将参加2015年美国北极探险队，以确定该地区氮的生物地球化学。 美国北极探险队的目标是与国际地理计划计划中的其他跨国公司计划相同，是确定过程并量化流量，以控制海洋中关键的微量元素和同位素的分布，并确定这些分布对不断变化环境条件的敏感性。一些痕量元素对生命至关重要，另一些是已知的生物毒素，而另一些则很重要，因为它们可以用作海洋中各种物理，化学和生物过程的示踪剂。氮是浮游生物在海洋中普遍要求的两种主要营养物质之一，这项在北极海洋中的研究将增加我们对海洋生态，生产力和碳循环的理解。这项研究还将为研究生和本科生提供培训，并将通过公共外展活动分享结果。与其他海洋盆地相比，北极氮知识的状态仍然粗略，尽管了解北极海洋氮循环是理解其全球生物地球化学的中心。首先，北极大陆架上的底栖氮损失可能代表了海洋固定氮的全球显着水槽。其次，北极大陆架上的底栖氮损失并坡度降低了硝酸盐与磷酸盐的比例，其比率大大低于浮游植物氮的平均要求，从而限制了西北极海洋中无冰表面的一级产生。鉴于北极气候学的快速变化，其生物地球化学的表征和建立基线以监测未来的变化至关重要。研究人员将在硝酸盐，亚硝酸盐，铵和氮气中使用稳定的N同位素（15n/14n）比，并针对溶解的，颗粒物，大气，雪和海冰样品确定的套件确定，以更好地限制植物中生物氮转化的空间和时间变化。 这项研究的结果将提供对水质量对区域氮预算的贡献的一阶理解，确定区域氮源和下水道，并诊断出在Chukchi架子上发生的重要生物氮转化以及中央盆地。