Collaborative Research: JGOFS (Arabian Sea): Effects of the Oxygen Minimum Zone on Mesozooplankton Distributions and Food Webs

9310591希望这项研究是阿拉伯海联合戈巴尔海洋通量研究的一部分，探讨阿拉伯海真光层以下普遍的亚氧条件是否将后生动物的碳循环主要限制在氧气最低层以上和以下的区域，以及这是否导致深海碳浓度(以浮游生物生物量的形式)增加。该项目有两个重点：(1)测量深海垂直地层中浮游动物的分布和不同大小的生物量，特别注意氧最小带及其上下界面，以及(2)研究氧最小带对浮游动物营养关系的影响，包括潜在的浮游动物-细菌联系。将在四季期间利用MOCNESS浮游生物网系统在四个密集的JGOFS站和站之间的横断面上每隔一段时间采集3500米以下的垂直分层浮游动物样本，以确定中浮游动物的分布和不同大小的生物量。将用透射电子显微镜分析浮游动物的肠道内容物，以确定营养网。潜在的细菌-浮游动物之间的联系将通过使用分子探针进行进一步的研究。氧气最小区域的上下界面可能是浮游动物和颗粒丰度较高的地方，也可能是有机物质密集加工的地方，将专门用于研究分布和食物网。最低含氧量范围内的低中浮游动物数量可能有助于增加有机物质向海底的通量，因为这些有害动物对中水中颗粒物质的利用将会减少。中浮游动物的高丰度和氧气最小带界面上的短食物链(细菌到浮游动物)表明，对位于狭窄深度窗口内的有机物质进行了密集的处理，可能起到了过滤下沉颗粒的作用。这项工作将有助于阐明有机物质如何在通过水柱进入海底的过程中发生变化。它将有助于理解阿拉伯海的季节性季风循环和由此产生的生产力高峰如何与碳通量和沉积相关联，并可能为预测气候变化的影响提供一些类比。

9310591 Wisher This research, part of the Joint Gobal Ocean Flux Study (JGOFS) of the Arabian Sea, addresses the question of whether the widespread suboxic conditions below the euphotic zone in the Arabian Sea restrict carbon cycling by metazoans primarily to regions above and below the oxygen minimum zone and whether this results in elevated carbon concentrations (in the form of plankton biomass) at depth. This project has two foci: (1) the measurement of mesozooplankton distributions and size-fractionated biomass in vertical strata to the deep sea, with particular attention to the oxygen minimum zone and its upper and lower interfaces, and (2) examination of oxygen minimum zone effects on zooplankton trophic relationships, including the potential zooplankton-bacteria link. Vertically stratified zooplankton samples down to 3500 m will be taken during four seasons with a MOCNESS plankton net system day and night at the four intensive JGOFS stations and at intervals along transects between the stations for the determination of mesozooplankton distributions and size-fractionated biomass. Gut contents of zooplankton will be analyzed by transmission electron microscopy for determination of trophic webs. The potential bacteria-zooplankton link will be investigated further with the use of molecular probes. The upper and lower interfaces of the oxygen minimum zone, which may be locations of high zooplankton and particle abundances and intense processing of organic material, will be specially targetted for studies of distributions and food webs. Low mesozooplankton abundances within the oxygen minimum zone may contribute to enhanced fluxes of organic materials to the sea floor, because the utilization of particulate material in midwater by these detritivores would be reduced. High mesozooplankton abundances and a short food chain (bacteria to zooplankton) at the oxygen minimum zone interfaces would suggest intense processing of organic material localiz ed within a narrow depth window, possibly acting as a filter for sinking particles. This work will help elucidate how organic material may be altered during passage through the water column to the sea floor. It will contribute to understanding how the seasonal monsoom cycle of the Arabian Sea and resultant productivity peaks are coupled to carbon fluxes and deposition and may provide some analogies for predicting effects of climate change.