Life Cycles of Diapausing Copepods in the Arabian Sea: cues for sinking at the end of the SW Monsoon

阿拉伯海滞育桡足类的生命周期：西南季风结束时下沉的线索

• 批准号: 1259255
• 负责人: Sharon Smith
• 金额: $ 54.92万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1259255&HistoricalAwards=false
• 关键词: Life; Cycles; Diapausing; Copepods; Arabian

Intellectual Merit. The infusion or transport of large-bodied copepods, whose life cycle includes diapauses (hibernation) at subsurface depths, into the upwelling area off Oman is fundamental to the success of the pelagic ecosystem in the region. Changes in the SW Monsoon wind pattern or strength can alter timing and intensity of upwelling and mixing, presenting the possibility that primary productivity during upwelling (dominated by diatoms) and the large-bodied, diapausing copepods that ingest phytoplankton, may become de-coupled. When decoupling has happened in other ecosystems, populations crash forcing a food web reorganization, often with outcomes that are undesirable. In the case of Oman, the abundant myctophid fish, a key link to upper trophic level fish of commercial importance, may be at risk for a significant population decline because of changes in the timing of primary production.Now that climate change may be altering the monsoon cycle of wind forcing in the Arabian Sea, there exists the possibility that the life cycle of diapausing C. carinatus may become mismatched with the appearance of their food supply occurring during the upwelling season. While ontogenetic migration is generally associated with high latitude environments, where the spring bloom of phytoplankton driven by the annual cycle of sunlight provides a spatially and temporally reliable food supply, there are no other copepods inhabiting the tropics and subtropics that have diapause at depth in their life cycle (except perhaps Subeucalanus crassus in the Arabian Sea). Understanding the cues that trigger downward migration of C. carinatus at the end of the upwelling season, and investigating whether S. crassus has a phenology similar to C. carinatus, are the goals of this project. An international archive of samples from the Arabian Sea extending back to 1992, as well as new samples, will be used in this study.Broader Impacts. Collaboration will continue with the Sultan Qaboos University in Muscat, Oman. The university is just 26 years old, and marine science in Oman is not much older in spite of the fact Oman has 1700 miles of coastline bordering the Sea/Gulf of Oman and the Arabian Sea. These collaborative efforts will extend times series observations that began six years ago off Masirah Island (located in the seasonal upwelling zone) with a goal of introducing Omanis to the value of sustained measurements in their coastal waters. There have been important successes, especially with the Beduin fishermen on Masirah Island, who have known their local waters for a lifetime, and recognize that dramatic changes are happening now. They are eager participants in the "knowledge gathering" such as making daily measurements of sea surface temperature. As fish kills and red tides proliferate in the coastal waters of Oman, and costly cyclones impact the coast with greater frequency, the value of sustained observations has become appreciated. In addition, the PI has recently co-authored two books on Arabian Sea plankton taxonomy and two more volumes are expected to result from the research.

知识价值。大型桡足类动物的生命周期包括在地下深处的滞育（冬眠），将它们注入或运输到阿曼附近的上升流区是该地区远洋生态系统成功的基础。西南季风风模式或强度的变化可以改变上升流和混合的时间和强度，这表明上升流期间的初级生产力（以硅藻为主）和以浮游植物为食的大型滞育桡足类动物可能会脱钩。当其他生态系统发生脱钩时，种群崩溃迫使食物网重组，结果往往是不受欢迎的。以阿曼为例，由于初级生产时间的变化，丰富的胞菌鱼（与具有商业重要性的高营养鱼类的关键环节）可能面临种群大量减少的危险。既然气候变化可能正在改变阿拉伯海风的季风周期，那么滞育C. carinatus的生命周期可能会与上升流季节出现的食物供应不匹配。虽然个体发生迁移通常与高纬度环境有关，在那里，浮游植物的春季开花由每年的阳光循环驱动，提供了空间和时间上可靠的食物供应，但没有其他生活在热带和亚热带的桡足类动物在其生命周期中有深度滞育（可能除了阿拉伯海的亚种）。了解在上升流季节结束时触发C. carinatus向下迁移的线索，并调查S. crassus是否具有类似于C. carinatus的物候学，是本项目的目标。本研究将使用阿拉伯海1992年以来的国际样本档案以及新样本。更广泛的影响。将继续与阿曼马斯喀特的苏丹卡布斯大学合作。这所大学只有26年的历史，尽管阿曼有1700英里的海岸线与阿曼海/阿曼湾和阿拉伯海接壤，但阿曼的海洋科学并没有太久。这些合作努力将延长六年前在Masirah岛（位于季节性上升流区）开始的时间序列观测，目的是向阿曼人介绍其沿海水域持续测量的价值。已经取得了重要的成功，特别是马西拉岛上的贝都因渔民，他们一生都熟悉当地的水域，并认识到现在正在发生巨大的变化。他们是“知识收集”的热心参与者，比如每天测量海面温度。随着阿曼沿海水域的鱼类死亡和赤潮激增，以及代价高昂的气旋更频繁地影响海岸，持续观测的价值已得到重视。此外，PI最近还与人合著了两本关于阿拉伯海浮游生物分类的书，预计还会有两卷书的出版。