The Controls of Sulfur Storage in Lake Sediments by Interactions among the Carbon, Iron, Oxygen and Sulfur Cycles

世界上许多地区的湖泊现在从酸沉积中获得了相当大的硫酸盐输入。Giblin、Peterson和Fry之前专注于由于硫酸盐负荷增加而在湖泊中发生的生物地球化学变化。他们的工作揭示了一些现有的关于湖泊中硫循环如何发挥作用的范例可能需要修改。研究人员现在从实验室培养和沉积物剖面中都有证据表明，碳限制了一些湖泊中硫酸盐的还原。在这项提案中，研究人员将重点放在几个问题上，这些问题是他们之前工作的直接结果。这些是：1)湖泊沉积物中硫储存的碳限制有多普遍？2)富营养化如何影响湖泊沉积物中储存的硫的数量和形态？3)铁的有效性是否影响许多湖泊沉积物中的硫储存？研究人员提出了一种多方面的实验方法，包括测量各种湖泊的沉积物元素剖面，在整个湖泊水平上进行新陈代谢研究，以及在野外和实验室环境中对变量进行实验操作。这种平衡的方法应该可以得出强有力的结论，说明C、N、Fe和P循环对硫酸盐负荷变化的响应，以及这些响应是如何被富营养化改变的。这项研究是由一个来自一家杰出机构的高素质团队进行的。这项工作的结果将为了解湖泊对富营养化和酸降水的响应提供重要的知识。

Lakes in many areas of the world now receive considerable inputs of sulfate from acid deposition. Giblin, Peterson, and Fry previously focused on the biogeochemical changes that occur in lakes due to increased sulfate loading. Their work revealed that some of the existing paradigms on how the sulfur cycle in lakes functions may need to be modified. The investigators now have evidence from both laboratory incubations and sediment profiles that carbon limits sulfate reduction in some lakes. in this proposal the investigators focus on several questions that are a direct outgrowth of their previous work. These are: 1) How widespread is carbon limitation of sulfur storage in lake sediments? 2) How does eutrophication influence the amounts and forms of sulfur stored in lake sediments? 3) Does iron availability effect sulfur storage in sediments in many lakes? The investigators propose a multifaceted experimental approach that includes the measurement of sediment element profiles from a variety of lakes, metabolic studies at the whole lake level, and the experimental manipulation of variables in field and laboratory settings. This balanced approach should allow robust conclusions about responses of the C,N,Fe, and P cycles to changes in sulfate loading, and how these responses are altered by eutrophication. This research is being conducted by a highly qualified team from an outstanding institution. The results of this work will provide important knowledge for understanding the responses of lakes to eutrophication and acid precipitation.