Roles of Bioactive Trace Metals and Trace Metal Chelators with Respect to Oceanic Phytoplankton Productivity in the Central Equatorial Pacific and Western North Pacific

该项目将通过改变生长所需的溶解微量金属（铁、锰和锌）的数量，以及那些可能有毒且经常存在的微量金属（铜和Co）的数量，来测试有关控制海洋初级生产力（主要是浮游植物生产力）的几个假设。在自然界中，这些金属与自然产生的有机化合物的络合程度可能控制它们对浮游植物的可利用性。这项研究将调查海洋的几个地区，这些地区没有充分利用溶解的营养物质硝酸盐和磷酸盐，可能是因为缺乏所需的微量金属或过量的有毒微量金属。将要进行的实验将包括：1)在几个站点确定溶解的微量金属随深度的浓度，以及2)在每个站点改变浮游植物培养物中微量金属铁、锰、锌、铜和钴的数量和可用性。第二组实验的结果将与浮游植物生长实验进行比较，其中没有添加额外的金属，以便量化痕量金属的不同可用性的大小。

This project will test several hypotheses regarding the control of oceanic primary productivity (primarily phytoplankton productivity) by varying the amounts of dissolved trace metals needed for growth (Fe, Mn and Zn) and also those which may be toxic and are often also present (Cu and Co). In nature the extent to which these metals are complexed by naturally occurring organic compounds may control their availability to the phytoplankton. This research will investigate several areas of the ocean which are underutilizing the dissolved nutrients nitrate and phosphate, perhaps because of lack of needed trace metals or excess of toxic trace metals. The experiments to be done will involve: 1) determining the concentrations of dissolved trace metals versus depth at several stations, and 2) at each station varying the amounts and availabilities of the trace metals Fe, Mn, Zn, Cu and Co in living phytoplankton cultures. The results of the second set of experiments will be compared with phytoplankton growth experiments wherein no additional metals have been added in order to quantify the magnitude of varying availabilities of the trace metals.