Collaborative Research: US GEOTRACES GP17-ANT: Characterizing the composition, scavenging efficiency and bioavailability of size fractionated particles

合作研究：美国 GEOTRACES GP17-ANT：表征尺寸分级颗粒的组成、清除效率和生物利用度

• 批准号: 2123303
• 负责人: Phoebe Lam
• 金额: $ 36.67万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123303&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

The Amundsen Sea adjacent to Antarctica has gained increasing attention because of rapid melting of glaciers that drain into it. While most of the scientific and media attention has focused on how melting glaciers will affect sea level rise, there are also important consequences for ocean chemistry and biology. Parts of the Amundsen Sea have the highest rates of photosynthesis of all open water regions surrounding Antarctica, and this may be because melting glaciers are supplying essential nutrients such as iron. A detailed understanding of how melting glaciers affect the supply and removal of nutrients including iron is necessary to predict the biological, chemical, and climate consequences of melting glaciers.This project aims to study this system by focusing on the role that marine particles play in the supply and removal of trace nutrient levels. Marine particles include all suspended, solid material in seawater that derive from biological, chemical, and geological processes. Some types of marine particles supply nutrients to seawater, whereas other types remove nutrients from seawater. The investigators will determine the concentrations and chemical compositions of marine particles in the Amundsen Sea in order to understand which types supply and which types remove nutrients from seawater. This work will clarify the essential role of particles in the supply and removal of nutrients in this quickly changing part of the world. This work will train undergraduate and graduate students from three public US institutions in the west coast (University of California, Santa Cruz), northeast (University of Rhode Island), and southeast (University of Georgia). This project will also support a journalist to participate in the cruise and pitch, report, and write stories from the expedition to communicate the results of this collaborative project to the public.The Amundsen Sea is a classic “warm Antarctic continental shelf”, where intrusions of warm Circumpolar Deep Water (CDW) onto the shelf have resulted in the highest glacial basal melt rates on the Antarctic Margin. The US GEOTRACES program has been funded for a 60-day research cruise in the Amundsen Sea to bring geochemical tools to study the biogeochemical consequences of this high melt. Particles are a key parameter for all GEOTRACES section cruises because of their importance in the supply, internal cycling, and removal of many trace elements and isotopes (TEIs). Previous cruises to the Amundsen Sea have suggested that particulate Fe, abundant in meltwater-influenced regions, may be helping to fuel the high NPP in the Amundsen. Particles also play an essential role in the removal of dissolved Fe and other particle-reactive TEIs via scavenging. Indeed, models have shown that scavenging by particles is by far the largest loss term for dissolved Fe (dFe), even larger than biological uptake when integrated over the entire water column. So far, particles have been represented only as particulate organic matter (POM). The inclusion of other particle types besides POM is likely important for scavenging: for example, Fe and Mn (oxyhydr)oxides have been shown to be 1-3 orders of magnitude more efficient at scavenging some TEIs compared to other particle types, including POM. Thus, the composition of particles, not just their concentration, is important for the scavenging removal of TEIs. To address this gap in the understanding of particle biogeochemistry in the Amundsen Sea, this project has the following three main goals: 1) To determine the distributions of major and minor phases (particulate organic carbon, opal, CaCO3, lithogenic particles, Fe oxyhydroxides, Mn oxides), and trace element and suspended particulate mass concentrations of size fractionated particles collected by in-situ filtration2) To determine the speciation and bioavailability of particulate Fe in the Amundsen Sea to assess its role as a source and sink of TEIs 3) To examine the factors affecting the formation, reactivity, and stability of Mn oxides in the Amundsen SeaThis 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.

由于冰川迅速融化，与南极洲相邻的Amundsen海已经引起了人们的关注。尽管大多数科学和媒体的关注都集中在融化冰川将如何影响海平面上升上，但对海洋化学和生物学也有重要影响。 Amundsen海的一部分的光合作用率最高，在南极洲周围的所有开放水域，这可能是因为融化冰川正在提供必需的营养素，例如铁。对融化冰川如何影响包括铁在内的供应和去除（包括铁）的详细理解对于预测熔化冰川的生物学，化学和气候后果是必要的。该项目旨在通过关注海洋颗粒在痕量营养水平的供应和去除方面的作用来研究该系统。海洋颗粒包括源自生物，化学和地质过程的海水中的所有悬浮固体物质。某些类型的海洋颗粒向海水提供营养，而其他类型的养分从海水中清除了养分。研究人员将确定Amundsen Sea海洋颗粒的浓度和化学成分，以了解哪种类型的供应以及哪种类型从海水中消除了养分。这项工作将阐明颗粒在世界快速变化的部分中供应和去除营养中的重要作用。这项工作将培训来自西海岸（加利福尼亚大学圣克鲁斯分校），东北（罗德岛大学）和东南（乔治亚州大学）的三个美国公共机构的本科生和研究生。该项目还将支持一名记者参与巡游，报告和撰写来自探险的故事，以将该协作项目的结果传达给公众。AmundsenSea是经典的“温暖的南极大陆架”，在那里，温暖的圆环深水（CDW）侵入到了最高的Glacial Basical Basic Bation Bation the Ant Antarcic contarcitic Marctic Marctic Marctic Marctic Marctic Marctic antarcict ant artarctic Marcctic har ant artarcial rincic the narf。美国的地理领域计划已用于在阿蒙森海进行的60天研究巡航，以携带地球化学工具来研究这种高融化的生物地球化学后果。粒子是所有地理位置部分巡航的关键参数，因为它们在供应，内部循环以及删除许多痕量元素和同位素（TEIS）方面的重要性。以前前往阿蒙森海的巡游表明，受融化的影响区域中丰富的颗粒物可能有助于为阿蒙森的高NPP加油。颗粒在去除溶解的Fe和其他颗粒反应性TEI中也起着至关重要的作用。实际上，模型表明，颗粒的清除是迄今为止溶解的Fe（DFE）最大的损失项，在整个水柱上整合时，颗粒的损失项（DFE）甚至比生物摄取大。到目前为止，颗粒仅表示为颗粒有机物（POM）。除了POM之外，还包含其他粒子类型对于清除可能很重要：例如，与其他粒子类型相比，Fe和Mn和Mn（Oxyhydr）氧化物在清除某些TEI时的效率更高1-3个数量级。这是颗粒的组成，不仅是它们的浓度，对于清除TEI的清除很重要。为了解决Amundsen海中粒子生物地球化学的理解，该项目具有以下三个主要目标：1）确定主要和次要阶段的分布（颗粒有机碳，蛋白石，蛋白石，CACO3，岩性颗粒，岩性颗粒，Fe氧化羟化物，MN氧化物，MN氧化物），以及透明型粒子的质量分析，以及悬浮的尺寸颗粒质量素质素质素材，该尺寸粒子粒子素质分析差异差异差异差异， specification and bioavailability of particular Fe in the Amundsen Sea to assess its role as a source and sink of TEIs 3) To examine the factors affecting the formation, reactivity, and stability of Mn oxides in the Amundsen SeaThis award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.