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

阿拉伯海表层甲壳类浮游动物的放牧和碳循环

• 批准号: 9310599
• 负责人: Sharon Smith
• 金额: $ 71.94万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-15 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9310599&HistoricalAwards=false
• 关键词: Grazing; Carbon; Cycling; Epipelagic; Crustacean

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

Smith 9310599 在阿拉伯海观察到地球上任何地方对海洋特性最强烈的原子层强迫，那里季节性反转的季风驱动快速流动的垂直广泛的洋流、复杂的涡流场、大范围的开放海洋上升流、沿海上升流和明显的混合层加深。 该地区的生产周期呈季节性波动。 在西南季风季节（包括6月至9月），由于强风，初级生产力达到最大，这不仅导致富含营养物质的深水上升，而且还将风尘输送到热带海洋的表层。 东北季风（10月至11月）和季风间期，初级生产力显着下降。 西南季风季节期间，浮游动物的生物量和次生生产力也有所提高。 根据索马里附近的早期研究，阿曼附近的表层浮游动物被认为在不同季风季节的物种组成上会发生显着变化，西南季风期间的生物量主要由快速生长的中型和大型浮游动物食草动物（例如 Calanoides 和 Eucalanus）主导。 在其他季节，这些食草动物在地下深处的数量减少。 相对较大、生长较快的食草动物的季节性出现在很大程度上决定了西南季风（上升流）期间阿拉伯海浮游动物群落的放牧影响。 放牧影响反过来又调节碳向深度的通量，是该地区碳沉积时空格局的重要因素。 在阿曼附近的阿拉伯海，可以结合对阿拉伯海中部常年贫营养区域的放牧对碳通量贡献的调查来研究由上升流区域放牧群落的大规模季节性变化驱动的碳通量。 大约 150 米处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。 将使用多个开/关网（MOCNESS）来研究上层中型和大型浮游食草动物的作用，以确定分布和丰度，特别关注有氧-低氧界面和孵化实验，以确定摄入、粪便颗粒产生和生长速率