U.S. GEOTRACES PMT: Measurement of the organic complexation and chemical lability of dissolved copper using multiple techniques

美国 GEOTRACES PMT：使用多种技术测量溶解铜的有机络合和化学不稳定性

基本信息

批准号：
1756415
负责人：
James Moffett
金额：
$ 26.33万
依托单位：
University of Southern California
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-03-01 至 2022-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1756415&HistoricalAwards=false
关键词：
U.S.GEOTRACES PMT Measurement organic

项目摘要

Copper (Cu) is an element in the ocean that is essential for life. Like many elements taken up by marine life, its concentrations in seawater are very low; however, Cu has a distribution in the water column that is different from other biologically essential elements. This difference may be attributed to the presence of a residual fraction in seawater that is virtually inert. This project seeks to understand what this material is, why it is so unreactive, and how it can eventually be 'cracked" and re-enter the biological cycle. A scientist from the University of Southern California (USC) will characterize the Cu chemistry during the US GEOTRACES Pacific Meridional Transect (PMT) cruise. This cruise is a north-south transect from Alaska to Tahiti that spans a wide range of water depths, temperatures, biology, and chemistry. The Cu measurements will be made alongside many other trace elements that have different chemistries. By comparing their behavior, coupled with the knowledge of each element?s chemical properties, the scientist will further our knowledge of what controls the behavior of Cu in the ocean. Training of graduate students and outstanding undergraduates in the speciation techniques is planned. The graduate students will also mentor high school students from inner city schools through the USC Young Investigators Program. The cruise and its findings will be incorporated into outreach activities and courses taught at USC, including a general education class for non-science majors.A scientist from USC hypothesizes that non-labile complexes will predominate in high-scavenging regimes and that labile forms will accumulate in older deep waters above a non-labile background pool. To quantify the distribution and chemical properties, two different speciation techniques will be used based on competitive ligand exchange. The first, adsorptive cathodic stripping voltammetry, was used on previous GEOTRACES sections. The second is based on a ligand exchange, liquid/liquid partition methodology developed by the researcher. Partitioning leads to physical separation of fractions that are reactive or not with the competitive ligand allowing the exchangeability of strongly complexed copper by using Cu-65 as a tracer. The tracer enables much slower reactions to be studied experimentally. Samples will be analyzed using isotope dilution by inductively coupled plasma-mass spectrometry. Samples will also be prepared for natural Cu isotope analysis of non-labile Cu by a colleague at USC (Seth John) to test the hypothesis that non-labile or semi-labile complexes contribute to the heavy isotope signature of dissolved Cu in seawater. The PMT enables high volume sample collection from deep waters at the terminus of the oceanic conveyor belt, along with data for particulate metals and isotope tracers of scavenging. Moreover, the relationship between labile and non-labile Cu can be studied over several distinct biomes, including high-nutrient, low chlorophyll regions and oligotrophic subtropical gyres along the PMT.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.

铜（CU）是海洋中对生命必不可少的元素。就像海洋生物所占据的许多元素一样，其在海水中的浓度也很低。但是，Cu在水柱中具有与其他生物学基本要素不同的分布。这种差异可能归因于实际上是惰性的海水中存在残留分数。 This project seeks to understand what this material is, why it is so unreactive, and how it can eventually be 'cracked" and re-enter the biological cycle. A scientist from the University of Southern California (USC) will characterize the Cu chemistry during the US GEOTRACES Pacific Meridional Transect (PMT) cruise. This cruise is a north-south transect from Alaska to Tahiti that spans a wide range of water depths, temperatures,生物学和化学测量将与许多其他化学的痕量元素进行比较，并了解每个元素的化学特性，科学家将进一步了解我们对研究生的培训者的培训者，这是我们对培训的培训。计划及其发现将纳入USC的外展活动和课程中，包括非科学专业的通用教育课程。为了量化分布和化学特性，将基于竞争性配体交换使用两种不同的物种技术。第一个吸附性阴极剥离伏安法，用于以前的地理位置部分。第二个基于研究人员开发的配体交换，液体/液体分区方法。分区会导致与竞争性配体有反应性或不使用竞争性配体的物理分离，从而可以将CU-65用作示踪剂，从而允许强烈复杂的铜交换。示踪剂可以通过实验研究大量较慢的反应。将通过电感耦合等离子体质谱法分析样品。样本还将准备好由USC（Seth John）的同事对非同位素CU进行天然CU同位素分析，以检验以下假设：非标准或半长脂配合物有助于海水中溶解的Cu的重量同位素特征。 PMT可从海洋传送带末端的深水中收集大量样品，以及颗粒金属和清除的同位素示踪剂的数据。此外，可以在PMT上进行几种不同的生物群落研究，包括高氮，低叶绿素区域和寡嗜性亚热带回旋之间的关系。该奖项反映了NSF的法定任务，并认为通过基金会的知识优点和广泛的crietia crietia criperia criperia criperia criperia criperia criperia criperia criperia criperia，这一奖项沿PMT进行了研究。