Research on Ocean-Atmosphere Variability and Ecosystem Response in the Ross Sea: Dimethylsulfide Dynamics

摘要P.I.Giacomo DiTullio OPP97-25800初步的二甲基硫化物和二甲基磺基丙酸酯的数据表明，南极棕囊藻在罗斯海的碳和硫循环中起着重要作用。较高的沉积物DMSP和DMS浓度，加上深(400米)的荧光峰，表明与棕囊藻水华相关的碳输出通量可能被严重低估。棕囊藻向深水的相关碳通量也可能对冰川铁假说有重要影响。例如，如果亚南极地区发生了硅酸盐枯竭，那么在最后一次冰盛期期间增强的风成铁沉积可能优先刺激了棕囊藻的数量。棕囊藻在边缘冰区的水华可能会封存碳，并促进大气中二氧化碳的减少。这项拟议的研究将作为ROAVERRS项目的一部分，测量罗斯海水柱、沉积物和大气中的DMS和DMSP浓度。特别是，我们建议确定罗斯海棕囊藻水华对深水和底栖动物的碳和硫通量的意义。浮游植物种类组成将与DMS动态和DMSP向沉积物的通量进行比较。此外，还将研究DMS和DMSP的循环，以及DMS生产/消费与大气浓度之间的关系。

Abstract P.I. Giacomo DiTullio OPP97-25800 Preliminary dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) data indicate that Phaeocystis antarctica plays an important role in carbon and sulfur cycling in the Ross Sea. High sediment DMSP and DMS concentrations, coupled with deep ( 400m) fluorescence peaks, suggest that the carbon export flux associated with Phaeocystis blooms may be significantly underestimated. The Phaeocystis-associated carbon flux to deep water also may have important implications for the glacial iron hypothesis. For example, if silicate depletion in the subantarctic zone occurred, then enhanced eolian iron deposition during the last glacial maximum may have preferentially stimulated Phaeocystis populations. Phaeocystis blooms in the marginal ice zone may sequester carbon and promoted a decrease in atmospheric pCO2. The proposed research will measure DMS and DMSP concentrations in the water column, sediments and in the atmosphere of the Ross Sea as part of the ROAVERRS project. In particular, we propose to determine the significance of Phaeocystis blooms in the Ross Sea to carbon and sulfur fluxes to deep water and to the benthos. Phytoplankton species composition will be compared to DMS dynamics and to DMSP fluxes to the sediments. In addition, the cycling of DMS and DMSP, and the relationship between DMS production/consumption and atmospheric concentrations will be examined.