Biogeochemical Consequences of Metal Partitioning in Phytoplankton

9617675 Fisher海洋表层水体中许多微量元素的生物地球化学循环受到生物过程的强烈影响。尽管如此，对于元素一旦被纳入生物量，是什么控制了它们的命运，人们所知相对较少。例如，金属可以被吸收到食物网中，或再生到溶解相，或以下沉颗粒的形式输出。鉴于我们对这一领域缺乏了解，目前很难预测在广泛的海洋环境中金属循环中不同途径的命运和相对重要性。在此，主要研究人员首次提出了亚细胞分配和金属化学计量对自然系统中金属生物地球化学的影响，以促进我们对痕量金属循环的理解。有两种主要的方法，包括实验室和实地工作。实验室研究使用受控测量和标记的金属放射性核素来检查碳与金属的比例以及金属与生物质结合的分配和命运。一种新的双重标记技术允许主要研究人员在细胞间和细胞表面金属池之间进行分离。在实地，将检查浮游植物的自然组合，以了解各种金属的细胞分配，并将进行船上孵化实验，以检查金属的周转速度。这项研究的结果将大大增加我们对生物过程在海洋化学循环和运输中的作用的理解。

9617675 Fisher The biogeochemical cycling of many trace elements in ocean surface waters is strongly influenced by biological process. Despite this fact, relatively little is known about what controls the fate of elements once they are incorporated into biomass. For example, metals can be assimilated into the food web, or regenerated to the dissolved phase or exported on sinking particles. Given our lack of understanding in this area, it is difficult at present to predict the fate and relative importance of different pathways in metal cycling throughout the wide range of oceanic settings. The principal investigators propose here to advance our understanding of trace metal cycling by quantifying for the first time the effects of subcellular partitioning and metal stoichiometires on metal biogeochemistry in natural systems. There are two main approaches, consisting of laboratory and field work. The lab studies use controlled measurements and labeled metal radionuclides to examine carbon:metal ratios and the partitioning and the fate of metals incorporated into biomass. A novel dual labeling technique allows the principle investigators to separate between intercellular and cell surface pools of metals. In the field, natural assemblages of phytoplankton will be examined for the cellular partitioning of the various metals, and ship board incubation experiments will be conducted to examine the rates of metal turnover. The results of this study will significantly increase our understanding of the role of biological processes in chemical cycling and transport in the oceans.