Distribution, Biomass and Ecological Role of Macrozooplankton and Fishes in the Arabian Sea and Equatorial Indian Ocean

9415601 MADIN本项目的目标是确定阿拉伯海大型浮游动物和鱼类的丰度和分布，并估计它们对这些环境中有机物质垂直通量的贡献。季风强迫的阿拉伯海生态系统是世界上生产力最高的生态系统之一，但在生产和沉积方面存在鲜明的季节性对比。该系统在其动物群的分布和比较以及将地表生产分配到水柱和海底的途径上都是不同寻常的。索马里沿海上升流带是支持高生物量、低多样性的远洋动物群的生产区，而赤道印度洋是典型的寡养区，有大量未知物种的高度多样性。在这些不同的系统中，大型生物体的排泄和垂直迁移等过程在调节垂直物质通量方面的作用仍有许多问题有待回答。这项研究的具体目标包括：1)确定大型浮游动物和鱼类的分布和丰度；2)确定浮游动物和鱼类的垂直迁移范围和时间；3)检查和量化大型浮游动物的胃内容物和排泄率；4)利用拖网收集资料，为其他调查人员同时进行的声学采样提供地面真实校正；5)分析阿拉伯海和邻近赤道印度洋大型浮游动物和鱼类的物种多样性和动物地理。我们的结果将有助于了解阿拉伯海和印度洋远洋生态系统的群落结构和营养动态。这些巡航将与JGOFS远洋过程巡航的两次同时进行，我们的数据将与JGOFS测量和了解阿拉伯海垂直通量的目标有关。

9415601 Madin The goal of this project is to determine the abundance and distribution of macrozooplankton and fishes in the Arabia Sea, and to estimate their contribution to the vertical flux of organic matter in these environments. The monsoonally forced Arabian Sea ecosystem is one of the most productive in the world, but with sharp, seasonal contrasts in production and sedimentation. The system is unusual in the distribution and comparison of its fauna, and in the pathways by which surface production is distributed into the water column and sea floor. The Somali coastal upwelling zone is a productive region supporting a high-biomass, low- diversity pelagic fauna, and the equatorial Indian Ocean is a typical oligotrophic zone with a high diversity of inadequately known species. Many questions remain to be answered on the role of such processes as defecation and diel vertical migration of large organisms in regulating vertical fluxes of material in these contrasting regimes. Specific objectives of the study include: 1) determination of distribution and abundance of macrozooplankton and fishes; 2) determination of the extent and timing of diel vertical migration of zooplankton and fish; 3) examination and quantification of stomach contents and egestion rates of macrozooplankton; 4) use of trawl collections to provide ground-truth calibration of concurrent acoustic sampling by other investigators; and 5) analysis of the species diversity and zoogeography of macrozooplankton and fishes in the Arabian Sea and adjacent equatorial Indian Ocean. Our results will contribute to understanding community structure and trophic dynamics in the Arabian Sea and Indian Ocean pelagic ecosystems. The cruises will be concurrent with two of the JGOFS Pelagic Process cruises, and our data will bear on JGOFS objectives of measuring and understanding vertical fluxes in the Arabian Sea.