Collaborative Research: The Biogeochemistry of DMS and Related Compounds in a Chemically Stratified Antarctic Lake

电话：+86-98 -15998 J. PriscuOPP98-18140 P.I. G.二甲基硫（DMS）是海洋排放的主要挥发性硫化物，占海洋至大气生物硫通量的90%。 据推测，由与DMS氧化产物相关的凝结核引起的云形成可以直接抵消温室气体产生的CO2的变暖效应。 尽管二甲硫醚和相关的锍化合物具有全球重要性，而且水生系统在二甲硫醚的产生中发挥着重要作用（特别是在南极地区），但二甲硫醚和相关的锍化合物的源和汇仍然不明确。 我们提议的多研究者实地和实验室研究将研究水柱和沉积DMS/DMSP（二甲基磺基丙酸盐）的地球化学，以及相关化合物（例如二甲亚砜，二甲基化多硫化物）在邦尼湖中的作用。 邦尼湖是一个相对简单的（没有湍流，没有食草动物和很少的大气交换）水生系统，因此为研究微生物介导的生物硫循环提供了一个非常容易处理的环境。 初步数据表明，DMS前体的最大水平发生在深叶绿素层的湖泊，一个区占主导地位的隐藻藻类。 此外，邦尼湖无光沃茨的二甲硫醚浓度是自然水生系统中记录的最高浓度之一。 这些观察结果表明，前体产生的营养区浮游植物下沉到无光沃茨和沉积物中，在那里它们被微生物分解为二甲基硫和其他含硫化合物。 拟议的研究将界定二甲基硫醚和相关化合物的来源和汇，并将其与整个生态系统功能联系起来。 将开发邦尼湖有机硫化合物的地球化学转化模型。

OPP 98-15998 P.I. J. PriscuOPP98-18140 P.I. G. DiTullioDimethylsulfide (DMS) is the dominant volatile sulfur compound emitted from the ocean and may represent up to 90% of the sea-to-air biogenic sulfur flux. It has been hypothesized that cloud formation caused by condensation nuclei associated with products of DMS oxidation can directly counteract warming effects of anthropogenically produced CO2. Despite the global importance of DMS and related sulfonium compounds, and the significant role of aquatic systems in DMS production (particularly in south polar regions), the sources and sinks of DMS and associated sulfonium compounds remain equivocal. Our proposed multi-investigator field and laboratory research will examine the biogeochemistry of water column and sedimentary DMS/DMSP (dimethylsulfoniopropionate), and the role of associated compounds (e.g. dimethylsulfoxide, dimethylated polysulfides) in Lake Bonney. Lake Bonney is a relatively simple (no turbulence, no grazers and little atmospheric exchange) aquatic system and therefore provides a highly tractable environment for investigating microbially mediated cycling of biogenic sulfur. Preliminary data suggest that maximum levels of DMS precursors occur in the deep-chlorophyll layer of the lake, a zone dominated by cryptophyte algae. In addition, DMS concentrations in the aphotic waters of Lake Bonney are among the highest recorded in a natural aquatic system. These observations indicate that precursors produced by trophogenic zone phytoplankton sink to the aphotic waters and sediments where they are microbially decomposed to DMS and other sulfur compounds. The proposed research will define the sources and sinks of DMS and associated compounds and relate them to overall ecosystem function. A model of biogeochemical transformations of organo-sulfur compounds in Lake Bonney will be developed.