The Behavior and Distribution of Particle-Reactive Radionuclide Tracers in Particulates, Colloids, and Solution in the Canada Basin of the Arctic Ocean

这项建议是调查的行为，提供同位素示踪剂的颗粒去除过程中的北冰洋加拿大盆地的一系列元素。 这些将包括铀和钍系列核素、钕和钚。 将强调颗粒、胶体和溶液之间的分配作用。 与其他海洋相比，这一区域的颗粒通量特别低，这是独一无二的，原因至少有两个：（一）这是北冰洋的一个基本特征，需要更好地理解沿着它对颗粒反应性污染物同化的影响;（二）仔细描述这一极端情况下的过程将为其他研究提供重要的参考点。 该提案纳入了目前关于胶体大小颗粒在清除痕量金属中的作用的想法，这是拟议工作的一个重要重点。 待检验的假设如下： “由于加拿大盆地的颗粒浓度较低，胶体在颗粒反应性放射性核素的循环中发挥着重要作用。" 早期对溶解有机碳和悬浮颗粒物浓度（SPM）的研究表明，加拿大海盆胶体物质的浓度与其他主要海盆相似，而SPM浓度比其他海盆低一个数量级。 为了验证这一假设，本研究将沿着以下几条调查路线进行：1. 长寿命的TH同位素和短寿命的同位素之间的颗粒，胶体和溶解的物种的分布将被测量在加拿大盆地水柱在大陆架，斜坡和深盆。 通过颗粒清除Pb和Po的去除率将从它们在水柱中的测量值计算，以与Th的去除率进行比较。 2. 测量了Nd同位素在颗粒、胶体和溶解态之间的分布。 3. 溶解和颗粒PU同位素在水柱中的分布将在不同的网站进行测量，其传输和去除率将通过与其他粒子反应性核素的比较进行研究。 这项研究的一个关键方面是将TH的短寿命同位素与长寿命Th同位素和稳定Nd同位素的数据相结合。

This proposal is to investigate the behavior of a range of elements that provide isotopic tracers for particle removal processes in the Canada Basin of the Arctic Ocean. These will include U- and Th-series nuclides, Nd and Pu. The role of partitioning between particulates, colloids, and solution will be emphasized. This region is unique in having exceptionally low particle fluxes compared with other oceans for at least two reasons: (i) It is a fundamental characteristic of the Arctic Ocean that needs to be better understood along with the implications it has for the assimilation of particle-reactive contaminants, and (ii) a careful characterization of the processes in this extreme case will provide an important reference point for other studies. This proposal incorporates current ideas about the role of colloid-size particles in the removal of trace metals by scavenging and this is an important focus of the proposed work. The hypothesis to be tested is as follows: "Due to low particle concentration in the Canada Basin, the colloids play a major role in the cycling of particle-reactive radionuclides." Earlier studies on the dissolved organic carbon and suspended particle concentration (SPM) indicate that the concentration of colloidal material in Canada Basin is likely similar to other major ocean basins while the SPM concentration is about an order of magnitude lower than that of other ocean basins. In order to test the hypothesis, the study will focus along the following lines of investigation: 1. The distribution of the long-lived TH isotopes and short-lived isotopes between particles, colloids, and dissolved species will be measured in the Canada Basin water column in both continental shelf, slope and deep basin. The removal rate by particulate scavenging of Pb and Po will be calculated from their measurement in the water column for comparison with the removal of Th. 2. The distribution of Nd isotopes between particles, colloids and the dissolved species will be m easured. 3. The distribution of dissolved and particulate PU isotopes in the water column will be measured at various sites and their rates of transport and removal will be investigated by comparison with other particle-reactive nuclides. A key aspect of the study is the combining of data for the short-lived isotopes of TH with the long lived Th isotopes and stable Nd isotopes.