Collaborative Research: Particle Scavenging Controls on Trace Element Distributions

合作研究：微量元素分布的粒子清除控制

• 批准号: 2124317
• 负责人: Jess Adkins
• 金额: $ 13.96万
• 依托单位: California Institute of Technology
• 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: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2124317&HistoricalAwards=false
• 关键词: Collaborative; Research; Particle; Scavenging; Controls

Nearly all of the photosynthesis in the oceans is carried out by microscopic, single-cell “plants” called phytoplankton. The photosynthesis by phytoplankton forms the base of the food chain, supporting almost all life in the oceans. One of the key nutrients that phytoplankton need to grow is iron, which is often in short supply in ocean surface waters and can limit the phytoplankton growth and photosynthesis rates. This project seeks to better understand the cycling of iron in the oceans, focusing on the removal of iron from the oceans by particle scavenging. Particle scavenging refers to dissolved iron sticking to large, sinking particles, which ultimately remove iron to the sediments. This modeling study will simulate iron cycling in the oceans, along with the cycling of several different metal isotopes, that are also subject to removal by particles scavenging, but do not act as nutrients for phytoplankton. This will help separate the biological influences on iron distributions, from the impacts of particle scavenging and other physical processes. The external sources of iron to the oceans coming from dust deposition, ocean sediments, river runoff, and the seafloor hydrothermal vents will also be evaluated. This work is important for understanding how climate change and human activities will modify the iron cycle and impact biogeochemistry in the future. This project will also support two graduate students and an undergraduate student researcher. The model simulations will be evaluated and constrained with extensive comparisons to field measurements of iron and the other key variables. The GEOTRACES program has recently produced a global set of ship measurement surveys, with full depth measures of numerous isotopes and trace elements, including iron, that are ideal for evaluating the prognostic ocean model (Community Earth System Model (CESM) ocean component). The GEOTRACES datasets are also ideal for incorporation into our offline, inverse model (OCIM, CYCLOCIM) which can interpret the still sparse observations in the context of 3D circulation and biogeochemistry. The simulations of 230Th, 232Th, 231Pa, and Fe cycling will improve mechanistic understanding of particle scavenging and place stronger observational constraints on the patterns and magnitude of external lithogenic sources of trace elements to the oceans. Results and products from this study, with the ocean model component of the Community Earth System Model (CESM), will be incorporated into future versions of CESM, to improve the current ability to predict how ocean biogeochemistry and marine ecosystems will respond to climate change along a range of potential future climate trajectories.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.

海洋中几乎所有的光合作用都是由称为浮游植物的微观单细胞“植物”进行的。 浮游植物的光合作用构成了食物链的基础，支撑着海洋中几乎所有的生命。 浮游植物生长所需的关键营养物质之一是铁，而铁在海洋表面沃茨中通常供应不足，并且会限制浮游植物的生长和光合作用速率。 该项目旨在更好地了解铁在海洋中的循环，重点是通过颗粒清除从海洋中去除铁。 颗粒清除是指溶解的铁粘附在大的下沉颗粒上，最终将铁去除到沉积物中。 这项建模研究将模拟海洋中的铁循环，沿着几种不同金属同位素的循环，这些同位素也会被颗粒清除，但不会作为浮游植物的营养物质。 这将有助于将生物对铁分布的影响与颗粒清除和其他物理过程的影响分开。 还将评估来自灰尘沉积、海洋沉积物、河流径流和海底热液喷口的海洋铁的外部来源。 这项工作对于了解气候变化和人类活动将如何改变铁循环和影响未来的地球化学具有重要意义。 该项目还将支持两名研究生和一名本科生研究员。将通过与铁和其他关键变量的现场测量进行广泛比较，对模型模拟进行评估和约束。 GEOTRACES方案最近制作了一套全球性的船舶测量调查，对包括铁在内的许多同位素和微量元素进行了全深度测量，这是评价预测海洋模型（共同体地球系统模型海洋部分）的理想选择。 GEOTRACES数据集也非常适合纳入我们的离线逆模型（OCIM，CYCLOCIM），该模型可以在3D环流和地球化学的背景下解释仍然稀疏的观测结果。 230 Th，232 Th，231 Pa和Fe循环的模拟将提高粒子清除的机制理解，并将更强的观测约束的模式和规模的微量元素的海洋外部成岩源。这项研究的结果和产品，以及共同体地球系统模型（CESM）的海洋模型部分，将被纳入未来版本的CESM，提高当前预测海洋生物地球化学和海洋生态系统将如何沿着一系列潜在的未来气候轨迹对气候变化做出反应的能力。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响审查标准。