Collaborative Research: The importance of particle disaggregation on biogeochemical flux predictions

合作研究：颗粒分解对生物地球化学通量预测的重要性

基本信息

批准号：
2326735
负责人：
Matthew Rau
金额：
$ 41.06万
依托单位：
George Washington University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-03-15 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2326735&HistoricalAwards=false
关键词：
Collaborative Research importance particle disaggregation

项目摘要

Collaborative Research: The importance of particle disaggregation on biogeochemical flux predictionsParticle settling is one of the major ways that material in surface waters reaches the deep ocean. Particulate matter in the open ocean consists primarily of organic material from plankton and other biological detritus, which can readily aggregate to form large flocs. A combination of physical, chemical, and biological processes transforms these flocs as they settle, redistributing material throughout the water column and potentially sequestering elements such as carbon in the deep ocean. The impact of these transformations is affected by the sinking speed of these flocs, with larger and denser particles settling faster than smaller, less-dense ones. One of the key questions facing oceanographers today is what controls particle settling speed (for example, particle size, shape, and density). There is considerable evidence that particles readily break apart as they settle, decreasing their average size and settling speed, but it is not yet understood what conditions cause these disaggregation events. This work will measure the breakup characteristics of organic settling particles both in the laboratory and at sea to quantify the importance of these breakup processes relative to particle transport. The work will be done at the Pennsylvania State University in collaboration with the University of Georgia to target the development of future marine particle disaggregation models for use by the oceanographic community.This research will play an important role in determining the importance of disaggregation on the vertical transport of particulate matter in the ocean. The project will quantify the breakup of organic marine aggregates due to fluid forces caused by turbulence or swimming organisms. Phytoplankton will be cultured and formed into aggregates in the lab prior to disaggregation using calibrated turbulence. The size, shape, and structure of these aggregates before and after breakup will be quantified using high-speed visualization and holographic imaging. In addition to the laboratory measurements, a deployable instrument that can disrupt particles in-situ and measure their size and shape will be built and deployed in the North Atlantic during the spring bloom of phytoplankton. Detailed measurements of particle concentrations, breakup characteristics, organic content, and ambient turbulence as a function of depth in the water column will be collected. This work will represent the first study of marine aggregate breakup in-situ. Specifically, the project will clarify: (1) under what conditions disaggregation is important, (2) how strong different types of natural marine aggregates are and how their strength varies with size, composition, and morphology, and (3) how aggregate size, composition, and structure influences the distribution of its breakup mass. This project will advance the career of a doctoral student and engage numerous undergraduate researchers with the field of ocean science.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.

协作研究：粒子分解对生物地球化学预测粒子沉降的重要性是地表水中物质到达深海的主要方式之一。露天海洋中的颗粒物主要由浮游生物和其他生物碎屑的有机材料组成，这些材料可以很容易地聚集以形成大泡沫。物理，化学和生物学过程的结合会在沉降时转化这些泡沫，在整个水柱中重新分布材料以及潜在的隔离元素，例如深海中的碳。这些转换的影响受这些泡沫的下沉速度的影响，其较大且密集的颗粒比较小，较小的粒子更快地沉降。当今海洋学家面临的关键问题之一是控制粒子沉降速度的原因（例如粒径，形状和密度）。有大量证据表明，粒子在沉降时很容易分解，降低了平均大小和沉降速度，但尚不清楚导致这些分解事件的条件。这项工作将测量实验室和海上有机沉降颗粒的分裂特性，以量化这些分裂过程相对于粒子传输的重要性。这项工作将在宾夕法尼亚州立大学与佐治亚大学合作，以针对未来的海洋粒子分解模型的开发，以供海洋学界使用。这项研究将在确定分类在海洋中颗粒物垂直运输的重要性方面起着重要作用。由于湍流或游泳生物引起的流体力，该项目将量化有机海洋骨料的破裂。浮游植物将在实验室中培养并形成在实验室中的聚集体，然后使用校准的湍流进行分解。分解前后这些聚集体的大小，形状和结构将使用高速可视化和全息成像进行量化。除了实验室测量外，在浮游植物春季春天，将在北大西洋上建造和部署一种可部署的仪器，该工具可以破坏颗粒并测量其大小和形状。将收集粒子浓度，分解特性，有机含量和环境湍流作为水柱中深度的详细测量。这项工作将代表原位海洋分解的首次研究。具体而言，该项目将澄清：（1）在什么条件下分解很重要，（2）不同类型的天然海洋聚集体的强度如何以及它们的强度如何随尺寸，组成和形态而变化，以及（3）骨料大小，组成和结构如何影响其分裂质量的分布。该项目将推动博士生的职业生涯，并通过海洋科学领域与众多本科研究人员互动。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准通过评估来支持的。