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年厄尔尼诺现象是否会导致加拉帕戈斯潮下带生态系统的政权转变？如果是这样的话，是什么样的门槛推动了从拥有丰富珊瑚的岩石潮下带群落到藤壶主导政权的变化？ 制度变迁是非线性的“生态惊喜”，因为终点是不可预测的，是驱动变量的线性结果。该项目的工作假设是，即将到来的2014-2015年厄尔尼诺现象将产生非线性影响，对在厄尔尼诺/南方涛动极端温度变化期间漂白的珊瑚不利，但对依赖藤壶食物的底栖（底栖）食物链有利。 在加拉帕戈斯开展的具体工作将有助于人们普遍了解气候压力对海洋生态系统的非线性影响，这已被强调为了解气候变化对生态系统的影响所需的一个重要信息缺口。该研究还将为保护珊瑚的最佳做法提供信息，珊瑚在世界范围内受到多种压力因素和累积的直接和间接影响的威胁。这个为期一年的项目将对从高中生到研究生的各个层次产生更广泛的教育影响。 例如，该研究计划将为布朗大学的博士生在潮下带生态学和气候科学方面提供宝贵的指导。本科生将受益于在布朗大学的大型生态学课程中对气候振荡的生态影响的增强讲座和实验室培训。该研究小组致力于通过向当地高中介绍研究成果来促进海洋和气候变化知识，从而将外联范围扩大到这些场所之外。 厄尔尼诺等扰动可能会将生态系统推向临界点，因为阈值被超过，并突然过渡到一种不同的状态（制度）。由于预计极端厄尔尼诺现象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厄尔尼诺/南方涛动如何在气候变化的背景下影响海洋群落。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年北方半球夏季至冬季发生厄尔尼诺现象的可能性为70- 80%。该项目利用关于加拉帕戈斯潮下带底栖生物群落结构的现有定量基线，对即将到来的2014-2015年厄尔尼诺现象在群落生态系统一级的影响作出12项预测。该研究采用了观察实验方法来测试预测，并确定是否对珊瑚造成额外的漂白压力，以及与ENSO相关的藤壶进一步增加，最终导致以珊瑚数量下降和藤壶及其捕食者增加为特征的生态系统状态（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.