Collaborative Research: RAPID: Nearshore settlement and hydrodynamics in Southern California during El Nino, and the transition to normal ocean conditions: boom and bust?

合作研究：RAPID：厄尔尼诺期间南加州近岸沉降和流体动力学，以及向正常海洋条件的过渡：繁荣与萧条？

• 批准号: 1630459
• 负责人: Jesus Pineda
• 金额: $ 9.9万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1630459&HistoricalAwards=false
• 关键词: Collaborative; Research; RAPID; Nearshore; settlement

Understanding how larvae are transported in the coastal ocean is key for characterizing the population fluctuations of marine organisms. Studies demonstrate that larvae of species that inhabit shallow waters can behaviorally respond to changing oceanographic conditions by moving vertically into currents that can promote their transport to coastal, nearshore habitats where they settle to bottom habitats and complete their life cycle. However, the oceanographic mechanisms that promote such transport, and how they might be impacted by infrequent events such as El Niño, are poorly resolved. Given that El Niño events might increase in frequency and magnitude under climate change, it is imperative to assess how El Niño affects larval transport and larval settlement. To this end, this study will use an unprecedented set of nearshore biological and physical measurements spanning pre-El-Niño, during El Niño, and the predicted return to El Niño neutral conditions, to test mechanistically how larval transport and settlement respond in a nearshore coastal environment. This project will also provide educational and research opportunities for students at the University of San Diego, a liberal arts university. At least one laboratory exercise demonstrating the impacts of El Niño on larval transport and settlement will be developed for undergraduate students, and students will be recruited to participate in all aspects of the project to provide them with hands-on research experience. This research will form the basis for the thesis work of at least one M.S. graduate student. Finally, given that the research falls within a Marine Protected Area, results will be broadly disseminated and shared with coastal managers and the CA Department of Fish and Wildlife.Larval transport and settlement are fundamental processes for understanding the population dynamics of benthic invertebrates. Previous studies and unpublished observations indicate that El Niño events profoundly impact community and population processes, and in Southern California, El Niño effects range from alteration of larval transport and settlement of local populations, to the geographic expansion of subtropical species. This research will test the hypothesis that the current (2015-2016) El Niño event will result in a reduction of barnacle larval transport and settlement in Southern California nearshore habitats. Two mechanisms might be involved; first, a deepening of the thermocline forced by El Niño would result in reduction of larval transport by internal tidal bores, a mechanism that requires shallowing of the thermocline. Second, the distribution of larvae of littoral barnacles would be deeper, more offshore, and less constrained to nearshore habitats during El Niño than in El Niño neutral conditions, resulting in a reduction of nearshore larval abundance and settlement. The effects of El Niño on nearshore circulation, hydrography, larval transport and settlement in Bird Rock, Southern California, will be measured by a) deploying an array of instrumentation to measure temperature, pressure (waves) and currents; b) measuring daily barnacle larval settlement, and; c) assessing cross-shore and depth distribution of invertebrate larvae. These observations will be contrasted with two years of comparable observations taken at Bird Rock in 2014 (El Niño neutral conditions) and 2015 (during El Niño). Additionally, the investigators will measure weekly settlement at Bird Rock, and at Dike Rock, a site 7 km to the north, where previous observations at the end of the 1997/1998 El Niño indicated that barnacle settlement was very high. This will enable the evaluation of the generality of the settlement response as El Niño conditions eclipse, and examination of how settlement varies along a coastline.

了解如何在沿海海洋中运输幼虫是表征海洋生物体人口波动的关键。研究表明，居住在浅水水域的物种的幼虫可以通过垂直移动到可以促进其运输到沿海，近岸栖息地的水流中来对变化的海洋条件做出反应，在那里它们定居至底部的栖息地并完成生命周期。但是，促进这种运输的海洋机制以及诸如厄尔尼诺之类的不经常事件的影响如何，它们的影响很差。鉴于在气候变化下厄尔尼诺事件可能会增加频率和幅度，因此必须评估厄尔尼诺现象如何影响幼虫运输和幼虫沉降。为此，这项研究将使用一套前所未有的近海生物学和物理测量值，这些生物和物理测量涵盖了Elniño期间，以及预测返回ElNiño中性条件，以机械地测试幼虫的运输和在近岸沿海环境中的响应。该项目还将为文科大学圣地亚哥大学的学生提供教育和研究机会。至少将为本科生开发至少一项实验室锻炼，证明厄尔尼诺对幼虫运输和设置的影响，将招募学生参加该项目的各个方面，以为他们提供动手的研究经验。这项研究将构成至少一个M.S.的论文工作的基础。研究生。最后，鉴于该研究属于海洋保护区，结果将与沿海经理和CA鱼类和野生动植物部进行广泛传播和共享。LARVAL运输和环境是了解底栖无脊椎动物的种群动态的基本过程。先前的研究和未发表的观察结果表明，厄尔尼诺事件会深刻影响社区和人口过程，在南加州，厄尔尼诺现象的影响范围从幼虫运输和当地人口的改变到亚热带物种的地理扩张。这项研究将检验以下假设：当前（2015-2016）厄尔尼诺事件将导致南加州近海栖息地的藤壶幼虫运输和环境减少。可能涉及两种机制；首先，厄尔尼诺尼诺强制强制的热跃层的加深将导致潮汐孔内部的幼虫运输减少，这种机制需要降低热阶线。其次，沿海藤壶的幼虫的分布比在厄尔尼诺现象中的近海更深，离岸更大，对近海栖息地的约束较少，导致近海幼虫抽象和环境的减少。 ElNiño对南加州鸟岩近海循环，水文，幼虫的运输和设置的影响将通过a）衡量，以测量一系列仪器以测量温度，压力（波浪）和电流； b）测量每日藤壶幼虫设置，并且； c）评估无脊椎动物幼虫的跨近岸和深度分布。这些观察结果将与2014年在Bird Rock（厄尔尼诺中性条件）和2015年（在Elniño期间）对鸟岩进行了两年可比的观察。此外，调查人员将每周在Bird Rock进行每周的设置，在Dike Rock（北部7公里）的Dike Rock，在1997/1998年结束时，ElNiño的先前观察表明，藤壶设置很高。这将使设置响应的通用性评估为厄尔尼诺（Elniño）条件日食，并检查定居方式沿海岸线变化。