RAPID - Assessing the response of the Seychelles-Chagos Thermocline Ridge ecosystem to an Indian Ocean Dipole event

RAPID - 评估塞舌尔-查戈斯温跃层海脊生态系统对印度洋偶极子事件的响应

• 批准号: 2019983
• 负责人: JOAQUIM GOES
• 金额: $ 19.18万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2019983&HistoricalAwards=false
• 关键词: RAPID; Assessing; response; Seychelles; Chagos

Phytoplankton constitute the base of the marine food web. Their diversity, productivity and abundance have a huge influence on fisheries. For example, seasonal increases in phytoplankton biomass caused by the surge of deep ocean nutrient rich waters into the upper sunlit layers in the Equatorial Indian Ocean lead to an increase in tuna stocks. However, non-periodic increases of sea surface temperatures in the Seychelles-Chagos Thermocline Ridge region in the eastern Equatorial Indian Ocean, a phenomenon known as the Indian Ocean Dipole, weakens deep ocean water surge, which seems to alter phytoplankton community structure and to reduce phytoplankton’s productivity to the detriment of tuna stocks. Yet, the impact from such unpredictable events is not fully understood. This project investigates the impacts of an ongoing Indian Ocean Dipole, one of the most severe on record, on phytoplankton. The broader impacts of the project relate to its value to inform fisheries management plans in that area. Data derived from this study is valuable to understand and predict wider changes in the food web in a region that is coming under increasing pressures of global warming. All the data is made publicly available.The research team is working with South Korean collaborators to understand how changes in phytoplankton biomass and in deep chlorophyll maxima may be linked to changes in phytoplankton productivity and growth rates due nutrient and/or iron limitation as a result of the weakening of deep-water upwelling. The team is also investigating the impact of the dipole event on cell size of dominating phytoplankton populations. Finally, they are testing if the phytoplankton community rely primarily on recycled as opposed to new nitrogenous nutrients for photosynthesis and growth during dipole events. The hypotheses are tested through extensive biological, hydro-chemical and biogeochemical measurements that include: 1) microscopic, Flow Cytometry, FlowCAM and HPLC pigment based analysis of phytoplankton biomass, community composition and size structure and Fast Repetition Rate based measurements of phytoplankton photosynthetic competency along a cruise track and different depths in the water column, and 2) on-deck incubation based photosynthesis and nutrient uptake experiments. In situ measurements and sample collection is carried out as part of the Korea-US inDian Ocean Scientific (KUDOS) Research Program cruise (April-May 2020) on board the Korea Institute of Ocean Sciences and Technology Ship R/V Isabu, one of the only multi-disciplinary oceanographic cruises planned for the Seychelles-Chagos Thermocline Ridge region during the dipole event.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

浮游植物构成海洋食品网的基础。他们的多样性，生产力和抽象对渔业产生了巨大影响。例如，赤道富裕的水域涌入赤道印度洋的上阳光层导致浮游植物生物量的季节性增加导致金枪鱼库存的增加。 However, non-periodic increases of sea surface temperatures in the Seychelles-Chagos Thermocline Ridge region in the Eastern Equatorial Indian Ocean, a phenomenon known as the Indian Ocean Dipole, weakens deep ocean water surge, which seems to alter phytoplankton community structure and to reduce phytoplankton’s productivity to the detriment of tuna stocks.但是，尚未完全理解这种不可预测的事件的影响。该项目调查了正在进行的印度洋偶极子，这是浮游植物对浮游植物的影响。该项目的更广泛影响与其价值有关，以告知该领域的渔业管理计划。从这项研究中得出的数据对于理解和预测面向全球变暖压力的地区的食物网的更广泛变化非常有价值。所有数据均可公开使用。研究团队正在与韩国合作者合作，以了解浮游植物生物量和深层叶绿素最大值的变化如何与浮游植物生产率和增长率的变化有关，因此由于养分和/或铁的限制而导致深水上升膨胀的弱化。该小组还正在调查偶极事件对浮游植物种群主导的细胞大小的影响。最后，他们正在测试浮游植物群落是否主要依靠回收，而不是与新的氮营养素相反，以用于偶极子事件期间的光合作用和生长。通过广泛的生物学，水化学和生物地球化学测量进行测试，其中包括：1）基于基于浮游植物的生物量，社区组成和尺寸结构以及基于快速重复速率的phytoplank photos and groptection的微观，流式细胞仪，流动型和HPLC色素分析的分析，以及在植物上的基于快速重复的测量值，并具有相同的水平。 2）基于甲板孵育的光合作用和养分吸收实验。作为韩国 - 美国印度洋科学（Kudos）研究计划巡航（2020年4月至5月至2020年）的一部分进行原位测量和样品收集使用基金会的知识分子优点和更广泛的审查标准，被认为值得通过评估来支持。

项目成果

Reviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian Ocean

• DOI: 10.5194/bg-17-6051-2020
• 发表时间: 2020-12
• 期刊: Biogeosciences
• 影响因子: 4.9
• 作者: T. Rixen;G. Cowie;B. Gaye;J. Goes;Helga do Rosário Gomes;R. Hood;Z. Lachkar;Henrike Schmidt;J. Segschneider;Arvind Singh