Grazing and Carbon Cycling by the Epipelagic Crustacean Zooplankton of the Arabian Sea

史密斯9310599 阿拉伯海是地球上大气对海洋特性最强的强迫作用之一，那里季节性逆转的季风驱动着快速流动的、垂直延伸的海流、复杂的涡流场、大规模的开阔洋上涌、沿海上涌和明显的混合层加深。 该地区的生产周期是季节性波动。 在西南季风季节（6月至9月），由于强风不仅使富含营养物质的深水上升，而且还将风尘输送到这一热带海洋的表层，初级生产力最大。 在东北季风期（11月至11月）和季风间期，初级生产力显着减少。 浮游动物的生物量和次级生产力也在西南季风季节升高。 根据早期的研究关闭索马里，阿曼的上层浮游动物被假设为经历了显着的变化，从一个季风季节到另一个物种组成，生物量在西南季风占主导地位的快速增长的中型和macrozoooacutonic食草动物，如Calanoides和Eucalanus。 在其他季节，这些食草动物在地下深处的丰度减少。 季节性出现的相对较大，快速增长的食草动物决定，在很大程度上，放牧的影响，浮游植物群落的发展，在阿拉伯海西南季风（上升流）。 放牧的影响，反过来调制的碳通量的深度，是一个重要的因素，在空间和时间模式的碳沉积在这一地区。 在阿曼的阿拉伯海，碳通量驱动的大型，季节性变化的上升流区的放牧社区可以结合调查与常年oligotrophi c区域的阿拉伯海中部的放牧贡献的碳通量进行研究。 位于大约150米处的氧气浓度的陡峭梯度将大多数上层食草动物限制在该深度以上的表层。 海洋上层中型和大型食草动物的作用将通过以下方法进行研究：多张开/闭网（MOCNESS），以确定分布和丰度，特别注意氧化-亚氧化界面和孵化实验，以确定摄食、粪粒产生和生长速率

Smith 9310599 Some of the strongest atomspheric forcing of oceanic properties anywhere on our planet is observed in the Arabian Sea where seasonally reversing monsoon winds drive fast- flowing, vertically extensive currents, complex eddy fields, broad-scale, open ocean upwelling, coastal upwelling and pronounced mixed-layer deepening. Cycles of production in this region are seasonal oscillations. During the southwest monsoon season (June-September inclusive), primary productivity is maximal owing to strong winds which not only cause the uplift of deep water rich in nutrient, but also deliver aeolian dust to the surface layer of this tropical ocean. During the northeast monsoon (October-November inclusive) and intermonsoon periods, primary productivity is markedly reduced. Biomass of zooplankton and secondary productivity are also elevated during the southwest monsoon season. Based upon earlier studies off Somalia, the epipelagic zooplankton off Oman is hypothesized to undergo significant changes in species composition from one monsoon season to another, with biomass during the southwest monsoon dominated by rapidly growing meso- and macrozooplanktonic grazers such as Calanoides and Eucalanus. These grazers exist in reduced abundance at subsurface depths during other seasons. The seasonal appearance of relatively large, fast growing grazers determines, to a large extent, the grazing impact of the zooplanktonic community on the phytoplankton assemblage that develops in the Arabian Sea during the southwest monsoon (upwelling). The grazing impact in turn modulates the flux of carbon to depth and is an important factor in the spatial and temporal patterns in carbon deposition in this region. In the Arabian Sea off Oman, carbon fluxes driven by large, seasonal changes in the grazing community of the upwelling area can be studied in combination with investigation of the grazing contribution to carbon fluxes associated with the perennially oligotrophi c region of the central Arabian Sea. A steep gradient in oxygen concentration located at approximately 150 meters acts to restrict most epipelagic grazers to a surface layer above this depth. The role of the epipelagic meso- and macrozooplanktonic grazers will be studied using: multiple opening/closing nets (MOCNESS) to determine distribution and abundance with particular attention to the oxic-suboxic interface and incubation experiments to determine ingestion, fecal pellet production, and growth rates