The Application of In-Situ CFF and TIMS to the Study of Oceanic Particle Dynamics

本研究的重点是量化大西洋盆地表层和深水中溶解、胶体、小颗粒和大颗粒大小类别之间的转化率。方法是使用高灵敏度的热电离质谱法和放射化学程序来确定各种尺寸类别的234、228Th和230Th。胶体相，传统上与滤液一起收集，将使用横流过滤技术进行原位采样。现场取样方法将包括使用过滤器（33um）收集大颗粒，以及使用原位横流过滤直接分离和收集胶体（5,000 NMW-0.2 um）和溶解（5,000 NMW）馏分。这些数据将使颗粒表面的吸附过程与胶体和悬浮颗粒的聚集/分解过程分离开来。特别是，胶体Th的质量贡献和胶体作为反应中间体在海洋颗粒循环和金属清除中的潜在重要作用将被评估。

The focus of this research is to quantify transformation rates between dissolved, colloidal, small particle, and large particle size classes in the surface and deep waters of the Atlantic basin. The approach is to use highly sensitive thermal ionization mass spectrometry and radiochemical procedures to determine 234Th, 228Th, and 230Th in the various size classes. The colloidal phase, traditionally collected along with the filtrate, will be sampled in-situ using a cross-flow filtration technique. Field sampling methods will involve the collection of large particles using filters (33um) and the direct separation and collection of colloidal (5,000 NMW-0.2 um) and dissolved (5,000 NMW) fractions using in-situ cross-flow filtration. These data will allow for a separation of the processes of sorption onto particle surfaces from the aggregation/disaggregation of colloids and suspended particles. In particular, the mass contribution of colloidal Th and the potentially important role colloids play as reactive intermediates in oceanic particle cycling and metal scavenging will be assessed.