RAPID: Understanding Thresholds and regime shifts in marine ecosystems: effects of the 2014-2015 El Nino in the Galapagos rocky subtidal

该项目解决的问题是：2014-2015年El Niño是否会导致加拉帕戈斯群岛潮下生态系统的政权转变？如果是这样的话，跨越了什么阈值来推动从拥有丰富珊瑚的潮下岩石群落到以藤壶为主的政权的变化？制度转移是非线性的“生态惊喜”，因为终点不能作为驱动变量的线性结果来预测。这个项目的工作假设是，即将到来的2014-2015年厄尔尼诺Niño将产生非线性效应，这对厄尔尼诺Niño南方涛动（ENSO）极端温度变化期间漂白的珊瑚是负面的，但对依赖藤壶为食物的底栖生物（海底栖息）食物链是积极的。加拉帕戈斯群岛的具体工作将有助于了解气候压力对海洋生态系统的非线性影响，这是了解气候变化对生态系统影响所需的关键信息缺口。这项研究还将为保护珊瑚提供最佳实践，珊瑚在世界范围内受到多种压力和累积的直接和间接影响的威胁。从高中生到研究生，这个为期一年的项目将对各个层次的学生产生更广泛的教育影响。例如，该研究项目将为布朗大学的一名潮下场生态学和气候科学博士生提供宝贵的指导。本科生将受益于布朗大学的大型生态学课程中关于气候振荡对生态影响的强化讲座，以及实验室的培训。研究小组致力于通过向当地高中介绍研究结果来培养海洋和气候变化知识，从而扩大其影响力。当超过阈值并突然过渡到另一种状态（制度）时，像El Niños这样的扰动可以将生态系统推向一个临界点。由于预计极端厄尔尼诺Niños的频率将随着气候变化而增加，因此迫切需要更全面地了解气候变化背景下enso如何影响海洋群落。目前，美国国家海洋和大气管理局（NOAA）气候预测中心预测，2014-2015年北半球夏冬期间发生厄尔尼诺Niño的概率为70- 80%。该项目利用加拉帕戈斯群岛潮下底栖生物群落结构的现有定量基线，对即将到来的2014-2015年厄尔尼诺Niño对群落生态系统水平的影响进行了12项预测。该研究采用观察实验的方法来测试预测，并辨别与这种ENSO相关的珊瑚额外的白化压力和藤壶的进一步增加是否最终导致珊瑚种群减少和藤壶及其捕食者增加的生态系统状态（制度）。

The question addressed in this project is: Does the 2014-2015 El Niño cause a regime shift in Galapagos subtidal ecosystems? And if so, what thresholds are crossed to drive the change from rocky subtidal communities with abundant corals to a barnacle dominated regime? Regime shifts are non-linear "ecological surprises" in the sense that the endpoint is not predictable as a linear outcome of a driver variable. The working hypothesis for this project is that the forthcoming 2014-2015 El Niño will create non-linear effects that are negative for corals which bleach during extreme temperature variability of the El Niño Southern Oscillation (ENSO), but are positive for the benthic (bottom dwelling) food chain dependent on barnacles for food. The specific work in the Galapagos will contribute to the general understanding of non-linear effects of climate stress in marine ecosystems, which has been highlighted as a critical information gap needed to understand the effects of climate change on ecosystems. The study will also inform best practices for the conservation of corals, which are threatened worldwide by multiple stressors and cumulative direct, and indirect impacts. Broader educational impacts of the one-year project will transpire at all levels from high school students to graduate students. For example, the research program will provide valuable mentoring of a Brown University PhD student in subtidal field ecology and climate science. Undergraduate students will benefit from enhanced lectures on ecological impacts of climate oscillations in a large Ecology course at Brown and from training in the lab. The research team is committed to expanding outreach beyond these venues by fostering ocean and climate change literacy in presentations about the research results to local high schools. Perturbations such as El Niños can drive ecosystems to a tipping point as thresholds are exceeded and a sudden transition to a different state (regime) occurs. Since the frequency of extreme El Niños is projected to increase with climate change, there is a pressing need to develop a more comprehensive understanding of how ENSOs affect marine communities in the context of climate change. Currently, the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center predicts a 70-80 % chance of an El Niño occurring during the northern hemisphere summer-winter of 2014-2015. This project leverages an existing quantitative baseline on benthic community structure in the Galapagos subtidal to address 12 predictions about community-ecosystem level impacts of the oncoming 2014-2015 El Niño. The research employs an observational-experimental approach to test the predictions and to discern if additional bleaching stress to corals and further increases in barnacles associated with this ENSO ultimately leads to an ecosystem state (regime) characterized by declining coral populations and increasing barnacles and their predators.