The Relationship Between Iron Availability and PhytoplanktonProductivity in the Southern Ocean

南大洋水域以其高浮游植物生产力而闻名。然而，熟悉南大洋的人知道，高生产力通常仅限于浅海陆架地区和冰缘水域；相比之下，近海几乎没有生产力，尽管该水域含有大量主要植物营养物质。对这一发现的一种可能的解释是，一种必要的微量元素或有机营养素缺失。尽管过去60年来一直在寻找支持这一想法的证据，但在最近开发出避免微量金属污染的超清洁技术之前，严格的测试是不可能的。马丁有证据表明，铁是限制性的微量元素。为了测试铁的存在与否是南极海洋浮游植物生产力变化的原因这一理论，马丁提议使用超清洁技术测量近岸和离岸南大洋水域以及冰样中的铁浓度。还将进行超清洁浮游植物富铁实验。检验缺铁假说很重要，因为如果不知道浮游植物没有利用主要营养物质的原因，就永远不会充分了解南极生态系统(S)。这些主要营养素的使用或不使用在决定全球大气二氧化碳水平方面起着重要作用。

Southern Ocean waters are famous for their high phytoplankton productivities. However, those familiar with the Southern Ocean know that the high productivity is generally confined to shallow shelf areas and to waters along the ice edge; in comparison, little productivity occurs offshore even though the waters contain massive amounts of major plant nutrients. One possible explanation for this finding is that an essential trace element or organic nutrient is missing. Although evidence supporting this idea has been sought for the past 60 years, rigorous testing was not possible before the recent development of ultra-clean techniques which avoid trace-metal contamination. Martin has evidence which suggests that iron is the limiting trace element. In order to test the theory that the presence or absence of iron is responsible for variations in Antarctic marine phytoplankton productivity, Martin proposes to measure iron concentrations in nearshore and offshore Southern Ocean waters and in ice samples using ultra-clean techniques. Ultraclean phytoplankton iron-enrichment experiments will also be performed. Testing the iron-deficiency hypothesis is important because the Antarctic ecosystem will never be adequately understood without knowing the reason(s) why major nutrients are not used by phytoplankton. The use or non-use of these major nutrients plays a significant role in determining global atmospheric carbon dioxide levels.