US GEOTRACES GP17-OCE and GP17-ANT: Atmospheric Deposition and Aerosol Fractional Solubility in Remote Ocean Regions

美国 GEOTRACES GP17-OCE 和 GP17-ANT：偏远海洋区域的大气沉降和气溶胶溶解度分数

• 批准号: 2049305
• 负责人: Clifton Buck
• 金额: $ 48.87万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049305&HistoricalAwards=false
• 关键词: US; GEOTRACES; GP17; OCE; ANT

Trace Elements are defined by their low concentrations in the open ocean and their addition and removal rates are key uncertainties in our understanding of ocean chemistry. In spite of their scarcity, trace elements can play an outsized role in determining where living things thrive in the open ocean. Near the coasts, these elements may be found in abundance because of features like rivers which bring source material from the continents to the ocean. Far from land, however, trace elements are scarce. The most significant source of these elements to the open ocean may come from dust and other particles falling onto the surface water either directly, or within rain droplets. An improved understanding of this process will further knowledge of element cycling in the ocean, including the carbon cycle. This project will sample the atmosphere of the South Pacific Ocean and the Pacific sector of the Southern Ocean around Antarctica. Input from the atmosphere to these waters is not well known and the research results will provide much needed information to the scientific community. This project will support an early career researcher as well as a graduate student.The deposition and subsequent dissolution of aerosols in surface waters remains a critical research area in the oceanographic community. Much of the ocean remains poorly sampled and improvements in flux estimates, chemical characterization, and fractional solubility estimates are necessary to improve the understanding of this important trace element source. This project will include a cruise in the South Pacific Ocean and one in the Amundsen Sea sector of the Southern Ocean, both as part of the GEOTRACES program. The cruise tracks will cover regions which lie downwind of dust producing regions of Australia and where atmospheric deposition could play a role in dictating distributions of trace elements in the water column. The flux of aerosols across the air-sea interface is a key research area within GEOTRACES and the broader oceanographic community. Flux from the atmosphere to the ocean is highly episodic making the capture of this important term difficult in the open ocean. Flux rates will be determined by the use of the cosmogenic isotope 7Be, providing a rate estimate for time scales longer than the cruise period. Aerosol trace element fractional solubility remains poorly constrained and is one of the reasons that biogeochemical models show poor agreement for marine trace element distributions. Aerosol dissolution will be tested in several solution of varying chemistry to provide a range of solubility estimates which are representative of conditions in precipitation, surface seawater, and in more aggressive environments which provide a high-end solubility estimate. Calculated terms like residence time are also poorly constrained due to this uncertainty. This project will address these questions by capturing bulk and size-fractionated aerosol samples as well as samples of precipitation. The study will advance understanding of dust and soluble aerosol trace element flux from the atmosphere to the ocean and provide contextual data for complimentary studies associated with these GEOTRACES section cruises.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.

微量元素的定义是它们在公海中的浓度较低，它们的添加和去除率是我们理解海洋化学的关键不确定因素。尽管微量元素稀缺，但它们在决定生物在公海中繁衍生息方面可以发挥巨大作用。在海岸附近，由于河流等特征，这些元素可能会大量存在，这些特征将大陆的原材料带到海洋。然而，远离陆地，微量元素稀缺。公海中这些元素最重要的来源可能来自直接落在地表水中或在雨滴中的灰尘和其他颗粒。加深对这一过程的了解将进一步了解海洋中的元素循环，包括碳循环。该项目将对南太平洋和南极洲周围南大洋太平洋部分的大气进行采样。从大气到这些水域的输入尚不清楚，研究结果将为科学界提供急需的信息。该项目将为一名早期职业研究员和一名研究生提供支持。地表水中气溶胶的沉积和随后的溶解仍然是海洋学界的一个关键研究领域。大部分海洋的采样仍然很差，需要改进通量估计、化学表征和溶解度分数估计，以提高对这一重要微量元素来源的了解。该项目将包括在南太平洋的一次巡航和在南大洋阿蒙森海区域的一次巡航，两者都是 GEOTRACES 计划的一部分。巡航路线将覆盖澳大利亚产尘区下风的区域，这些区域的大气沉降可能在决定水体中微量元素的分布方面发挥作用。气溶胶穿过海气界面的通量是 GEOTRACES 和更广泛的海洋学界的一个关键研究领域。从大气到海洋的通量是高度偶发性的，使得在公海中捕捉这个重要术语变得困难。通量率将通过使用宇宙成因同位素 7Be 来确定，提供比巡航周期更长的时间尺度的通量率估计。气溶胶微量元素溶解度分数仍然受到很弱的限制，这也是生物地球化学模型与海洋微量元素分布一致性较差的原因之一。将在不同化学性质的几种溶液中测试气溶胶溶解，以提供一系列溶解度估计值，这些溶解度估计值代表降水、表层海水和更具侵蚀性的环境中的条件，从而提供高端溶解度估计值。由于这种不确定性，计算出的术语（例如停留时间）也受到很少的限制。该项目将通过捕获散装和粒度分级气溶胶样本以及降水样本来解决这些问题。该研究将增进对从大气到海洋的灰尘和可溶性气溶胶微量元素通量的了解，并为与这些 GEOTRACES 部分巡航相关的免费研究提供背景数据。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。