Interactions between Cobalt, Cadmium, and Zinc Biogeochemistry and Phytoplankton Dynamics in the Ross Sea

这项拟议的工作扩展了一项跨学科船上计划的范围，该计划旨在通过在先前资助的项目中包括的铁成分中添加钴、镉和锌的痕量金属分析，来调查调节罗斯海南极藻类群分布和生产的环境因素。额外的微量金属分析将对巡航目标起到很大的补充作用，因为海洋浮游植物获取碳依赖于碳酸氢酶，这是一种金属酶，可以被这三种痕量元素中的任何一种激活。对罗斯海地区浮游植物丰度的研究表明，生产力由两个主要浮游植物类群主导：南极洲棕囊藻和硅藻。在高度分层的水域中，硅藻往往占主导地位，而在观察到更深混合的地方，棕囊藻占主导地位，这意味着棕囊藻在弱光条件下更有效。已经观察到棕囊藻种群导致光层中碳的快速和早期输出，这导致了一种假设，即如果气候导致的上层海洋层化增加，二氧化碳排放量可能会显著减少。***

The proposed work extends the scope of an interdisciplinary shipboard program to investigate the environmental factors that regulate the distribution and production of antarctic algal groups in the Ross Sea, by adding cobalt, cadmium, and zinc trace metal analyses to the iron component that had been included in a previously funded project. The additional trace metal analyses will be highly complementary to the cruise objectives because carbon acquisition by marine phytoplankton is known to be dependent on carbonic anhydrase, a metalloenzyme that may be activated by any of these three trace elements.Studies of phytoplankton abundances in the Ross Sea region have shown that productivity is dominated by two major phytoplankton groups: Phaeocystis antarctica and diatoms. Diatoms tend to dominate in highly stratified waters, while Phaeocystis is dominant where deeper mixing is observed, implying that Phaeocystis are more efficient under low light conditions. Phaeocystis populations have been observed to cause rapid and early export of carbon from the photic zone, leading to the hypothesis that CO2 drawdown could decrease significantly if climate-induced upper ocean stratification were to increase. ***