Collaborative Research: SGER - Rapid Resolution of Particle Sampling Issues for GEOTRACES

利用探索性研究小额赠款（SGER）的资金，加州大学伯克利分校和伍兹霍尔海洋学研究所的研究人员将参与美国-GEOTRACES相互校准研究的第一阶段，于2008年夏天在大西洋海上部署多单元大容量原位过滤系统（MULVFS）。 较大的采样方法偏差（有一个报告称瓶和泵之间的差异高达200倍，多个病例的差异为3倍或更多）继续困扰着微粒采样界。有充分的证据表明，MULVFS颗粒物样品不受偏倚的影响。此外，这样的采样偏差远远超出了目前资助的IC颗粒工作几乎完全旨在解决的分析方法问题，该项目的中心目标是消除对GEOTRACES计划颗粒采样的PI/采样方法的依赖，并协调在该计划的科学阶段使用的不同采样方法。 这项工作将支持多调查员利用多变量颗粒物系统在环境上容易的地点（如最佳可行技术）和在物理动态和生物可变的地点（如墨西哥湾流）进行颗粒物相互校准研究。 在具有挑战性和非挑战性的环境中与其他颗粒采样方法进行比较，将有助于理解和解决已发表文献中记录的实质性偏倚/差异，并在本提案中进一步记录。这样的内部校准以前从未进行过。另一个好处是，多边可变流量系统将通过提供上层水柱中痕量金属和核素的高分辨率基线剖面，大大提高2008年6月离子交换实验的效率。这个项目将解决非常真实的问题的方法依赖的粒子采样和预分析的偏见（某些泵的大量颗粒损失、瓶中过滤前的显著沉降损失、样品保存不良等）。这项工作与从事颗粒研究的海洋学界所有成员有关，因此与NSF化学和生物海洋学计划的广泛内容有关。

With funds from this Small Grant for Exploratory Research (SGER), researchers at the University of California at Berkeley and the Woods Hole Oceanographic Institution will participate in the first phase of the US-GEOTRACES Intercalibration study by providing deployment of the Multiple Unit Large Volume in-situ Filtration System (MULVFS) at sea in the Atlantic in the summer of 2008. Large sampling methodological biases (with one reported differences between bottles and pumps as large as a factor of 200, and multiple cases of factor of 3 or more differences) continue to confound the particulate sampling community. There is good evidence that MULVFS particulate matter samples are not subject to bias. Furthermore, such sampling biases far out weigh issues of analytical methodology issues that the currently funded IC particle work is almost exclusively designed to address.The central goal of this project is to eliminate PI/sampling approach dependency for the GEOTRACES Program particulate sampling and to reconcile the different sampling approaches to be used in the science phase of the Program. Work will support multi-investigator particulate matter intercalibration studies using MULVFS in both the environmentally easy locations such as BATS and in physically dynamic and biologically variable locations such as in the Gulf Stream. Comparison with other particle sampling methodologies in both challenging and non-challenging environments will lead to understanding and resolution of biases /differences that are both substantial, documented in published literature, and further documented in this proposal. Such an inter calibration has never been done before. A Further benefit is that MULVFS will greatly improve the efficiency of the June 2008 IC experiment by providing high resolution baseline profiles of trace metals and nuclides in the upper water column.Broader Impacts: This project will tackle the very real problems of method-dependent particle sampling and pre-analysis biases (large particle loss from some pumps, significant settling loss before filtration in bottles, poor sample preservation, etc.). The work is of relevance to all members of the oceanography community who engage in particle studies, and thus is of relevance to broad elements of the NSF Chemical and Biological Oceanography Programs.