Measuring Dissolved Gases to Reveal the Processes that Drive the Solubility Pump and Determine Gas Concentration in Antarctic Bottom Water

测量溶解气体以揭示驱动溶解度泵的过程并确定南极底水中的气体浓度

• 批准号: 1744562
• 负责人: Brice Loose
• 金额: $ 26.95万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1744562&HistoricalAwards=false
• 关键词: Measuring; Dissolved; Gases; Reveal; Processes

Near the Antarctic coast, polynyas are open-water regions where extreme heat loss in winter causes seawater to become cold, salty, and dense enough to sink into the deep sea. The formation of this dense water has regional and global importance because it influences the ocean current system. Polynya processes are also tied to the amount of sea ice formed, ocean heat lost to atmosphere, and atmospheric CO2 absorbed by the Southern Ocean. Unfortunately, the ocean-atmosphere interactions that influence the deep ocean water properties are difficult to observe directly during the Antarctic winter. This project will combine field measurements and laboratory experiments to investigate whether differences in the concentration of noble gasses (helium, neon, argon, xenon, and krypton) dissolved in ocean waters can be linked to environmental conditions at the time of their formation. If so, noble gas concentrations could provide insight into the mechanisms controlling shelf and bottom-water properties, and be used to reconstruct past climate conditions. Project results will contribute to the Southern Ocean Observing System (SOOS) theme of The Future and Consequences of Carbon Uptake in the Southern Ocean. The project will also train undergraduate and graduate students in environmental monitoring, and earth and ocean sciences methods. Understanding the causal links between Antarctic coastal processes and changes in the deep ocean system requires study of winter polynya processes. The winter period of intense ocean heat loss and sea ice production impacts two important Antarctic water masses: High-Salinity Shelf Water (HSSW), and Antarctic Bottom Water (AABW), which then influence the strength of the ocean solubility pump and meridional overturning circulation. To better characterize how sea ice cover, ocean-atmosphere exchange, brine rejection, and glacial melt influence the physical properties of AABW and HSSW, this project will analyze samples and data collected from two Ross Sea polynyas during the 2017 PIPERS winter cruise. Gas concentrations will be measured in seawater samples collected by a CTD rosette, from an underwater mass-spectrometer, and from a benchtop Membrane Inlet Mass Spectrometer. Noble gas concentrations will reveal the ocean-atmosphere (dis)equilibrium that exists at the time that surface water is transformed into HSSW and AABW, and provide a fingerprint of past conditions. In addition, nitrogen (N2), oxygen (O2), argon, and CO2 concentration will be used to determine the net metabolic balance, and to evaluate the efficacy of N2 as an alternative to O2 as glacial meltwater tracer. Laboratory experiments will determine the gas partitioning ratios during sea ice formation. Findings will be synthesized with PIPERS and related projects, and so provide an integrated view of the role of the wintertime Antarctic coastal system on deep water composition.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在南极海岸附近，冰穴是开放水域，冬季的极端热量损失导致海水变得寒冷，咸，密度足以沉入深海。这种稠密水的形成具有区域和全球重要性，因为它影响了洋流系统。Polynya过程也与海冰形成量，海洋热量损失到大气中以及南大洋吸收的大气CO2有关。不幸的是，影响深海水特性的海洋-大气相互作用在南极冬季很难直接观测。该项目将联合收割机与实验室实验相结合，调查溶解在海洋沃茨中的稀有气体（氦、氖、氩、氙和氪）的浓度差异是否与其形成时的环境条件有关。如果是这样的话，惰性气体浓度可以提供控制大陆架和底层水特性的机制的洞察力，并用于重建过去的气候条件。项目成果将有助于南大洋观测系统的主题“南大洋碳吸收的未来和后果”。该项目还将对本科生和研究生进行环境监测以及地球和海洋科学方法方面的培训。要了解南极沿海过程与深海系统变化之间的因果关系，就需要研究冬季冰间湖过程。冬季海洋热损失和海冰生成强烈影响了两个重要的南极水团：高盐度陆架水（HSSW）和南极底层水（AABW），进而影响海洋溶解度泵和南极翻转环流的强度。为了更好地描述海冰覆盖、海洋-大气交换、盐水排斥和冰川融化如何影响AABW和HSSW的物理特性，该项目将分析2017年PIPERS冬季巡航期间从罗斯海两个冰穴收集的样本和数据。气体浓度将在收集的海水样品中进行测量，这些样品由CTD玫瑰花、水下质谱仪和台式膜入口质谱仪收集。稀有气体浓度将揭示在地表水转化为HSSW和AABW时存在的海洋-大气（非）平衡，并提供过去条件的指纹。此外，氮（N2），氧（O2），氩，和CO2浓度将被用来确定净代谢平衡，并评估N2作为替代O2作为冰川融水示踪剂的功效。实验室实验将确定海冰形成过程中的气体分配比。研究结果将与PIPERS和相关项目进行综合，从而提供冬季南极海岸系统对深水组成的作用的综合观点。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Sea-ice production and air/ice/ocean/biogeochemistry interactions in the Ross Sea during the PIPERS 2017 autumn field campaign

• DOI: 10.1017/aog.2020.31
• 发表时间: 2020-09-01
• 期刊: ANNALS OF GLACIOLOGY
• 影响因子: 2.9
• 作者: Ackley, S. F.;Stammerjohn, S.;Parno, J.
• 通讯作者: Parno, J.

Instrument Bias Correction With Machine Learning Algorithms: Application to Field-Portable Mass Spectrometry

• DOI: 10.3389/feart.2020.537028
• 发表时间: 2020-12
• 期刊: Energy Procedia
• 作者: B. Loose;R. Short;S. Toler

Winter seal-based observations reveal glacial meltwater surfacing in the southeastern Amundsen Sea

冬季基于海豹的观测揭示了阿蒙森海东南部的冰川融水表面

• DOI: 10.1038/s43247-021-00111-z
• 发表时间: 2021
• 期刊: Communications Earth & Environment
• 影响因子: 7.9
• 作者: Zheng, Yixi;Heywood, Karen J.;Webber, Benjamin G. M.;Stevens, David P.;Biddle, Louise C.;Boehme, Lars;Loose, Brice
• 通讯作者: Loose, Brice

Frazil ice growth and production during katabatic wind events in the Ross Sea, Antarctica

• DOI: 10.5194/tc-14-3329-2020
• 发表时间: 2020-10-06
• 期刊: CRYOSPHERE
• 影响因子: 5.2
• 作者: Thompson, Lisa;Smith, Madison;Loose, Brice
• 通讯作者: Loose, Brice