Collaborative Research: Impact of Atmospheric Deposition on the Distribution and Speciation of Trace Elements in the Upper Ocean - Focus on Iron in the Sargasso Sea

合作研究：大气沉降对上层海洋微量元素分布和形态的影响 - 关注马尾藻海中的铁

• 批准号: 0926780
• 负责人: Peter Sedwick
• 金额: --
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926780&HistoricalAwards=false
• 关键词: Collaborative; Research; Impact; Atmospheric; Deposition

Recent studies in the Sargasso Sea (BATS region) have revealed a large, seasonal-scale change in the dissolved iron (Fe) concentration of the surface waters where concentrations decreased from ~1-2 nM in summer 2003, when aerosol Fe concentrations were high, to ~0.1-0.2 nM in spring 2004, when aerosol Fe concentrations were low. These changes were interpreted as the result of the seasonal dust input into the highly-stratified, oligotrophic surface waters during the summer, followed by the removal of this aeolian iron due to the convective mixing, biological uptake and particle scavenging during the winter-early spring. Researchers from the Bermuda Biological Station for Research, the University of Delaware and Woods Hole Oceanographic Institute have devised a simple model that implies that aeolian input of dissolved Fe into the surface ocean does not scale with total aerosol Fe concentrations. To test this hypothesis, the scientists will use the Sargasso Sea as a natural laboratory to carry out the following objectives: (1) achieve a quantitative understanding of the impact of mineral aerosol deposition (dry and wet) on the concentration and speciation of Fe in surface waters of the Sargasso Sea; (2) test the new model for aerosol Fe solubility that have been developed for the Sargasso Sea, and thus evaluate the potential for application of this model at the global scale; and (3) evaluate the need for an autonomous, buoy-mounted aerosol sampler for quantifying the concentration and solubility of aerosol iron over the open ocean. To attain these goals, both time-series observations and intensive process studies will be done. The work will include shipboard water-column sampling, atmospheric sampling at the Tudor Hill tower on Bermuda, the use of an autonomous aerosol sampler on the Bermuda Testbed Mooring, and subsequent analyses of the concentration and speciation of Fe and other trace metals in seawater, aerosol, and rainwater samples. As regards broader impacts, this study will provide needed data to improve predictive capabilities of biogeochemical-ecosystem models. In addition, this project will document the utility of an autonomous, buoy-mounted aerosol sampling systems linking atmospheric and oceanographic processes for environmental monitoring and research in marine geochemistry and biogeochemistry. The goals of this research are compatible with the focus of the SOLAS and GEOTRACES programs. One graduate student and one undergraduate student (funded as part of the REU program) from the University of Delaware will be trained as part of this project.

最近对马尾藻海（BATS 地区）的研究表明，地表水中的溶解铁 (Fe) 浓度发生了巨大的季节性变化，2003 年夏季，浓度从约 1-2 nM 下降，当时气溶胶 Fe 浓度很高2004 年春季，当气溶胶铁浓度较低时，降至约 0.1-0.2 nM。这些变化被解释为季节性尘埃在夏季输入到高度分层、贫营养的地表水中，随后由于冬季至早春期间的对流混合、生物吸收和颗粒清除而去除了风积铁。 。来自百慕大生物研究站、特拉华大学和伍兹霍尔海洋研究所的研究人员设计了一个简单的模型，该模型表明溶解铁进入表层海洋的风输入并不与气溶胶铁总浓度成比例。 为了检验这一假设，科学家们将利用马尾藻海作为天然实验室来实现以下目标：（1）定量了解矿物气溶胶沉积（干和湿）对水中铁浓度和形态的影响马尾藻海的表层水体； (2) 测试针对马尾藻海开发的气溶胶铁溶解度新模型，从而评估该模型在全球范围内的应用潜力； (3) 评估对自动浮标式气溶胶采样器的需求，以量化公海上气溶胶铁的浓度和溶解度。为了实现这些目标，将进行时间序列观察和深入的过程研究。 这项工作将包括船上水柱采样、百慕大都铎山塔的大气采样、在百慕大试验台系泊装置上使用自动气溶胶采样器，以及随后对海水中铁和其他微量金属的浓度和形态进行分析，气溶胶和雨水样本。至于更广泛的影响，这项研究将提供所需的数据，以提高生物地球化学生态系统模型的预测能力。 此外，该项目还将记录连接大气和海洋过程的自主浮标气溶胶采样系统在海洋地球化学和生物地球化学环境监测和研究中的实用性。 这项研究的目标与 SOLAS 和 GEOTRACES 计划的重点是一致的。 作为该项目的一部分，特拉华大学的一名研究生和一名本科生（作为 REU 计划的一部分资助）将接受培训。