RAPID- The implications of El Nino-related bleaching on coral recruitment in Moorea

这项研究探讨了2015-16年El-Niño对法属波利尼西亚珊瑚礁的影响，美国国家科学基金会在那里支持了一个长期生态研究站点。El Niño给太平洋带来了各种不同寻常的环境，但对珊瑚礁来说，最重要的影响是夏季海水变暖造成的。白化，导致珊瑚失去颜色和死亡的过程，是El Niño对珊瑚礁珊瑚负面影响的一个戏剧性例子，但高温也有潜在的影响，通过破坏繁殖和不良招募小珊瑚。因此，El Niño条件很可能与珊瑚礁在受到干扰后重新生长的能力下降有关，这可能会阻止完全恢复，或者有利于正在发展的群落发生实质性变化。这项研究建立在Moorea无与伦比的LTER调查历史的基础上，通过测量到达珊瑚礁的小珊瑚数量，生长的小珊瑚数量以及由于这些事件而发展的群落类型，来询问El Niño对珊瑚招募的影响。这项研究包括由教师和研究生在Moorea进行的实地考察，在此期间，将安装沉降瓦并监测小珊瑚，对小珊瑚的整体“健康”进行评估，并对自然和人工珊瑚礁表面进行量化，以促进社区发展。这项研究的结果将有助于了解海洋生态系统如何应对它们所面临的各种自然和人为干扰，包括全球气候变化，并将提高人们了解美国水域和全世界珊瑚礁将以何种形式生存到下个世纪的能力。该项目为研究生在国际背景下工作创造了独特的机会，他们将在那里进行研究，促进STEM职业发展，了解多样化的热带生态系统，以及气候变化在改变生态系统动态中的作用。通过将结果整合到当地高中的生命科学课程中，该项目的更广泛影响将得到加强，部分原因是在由加州州立大学北岭分校研究生组成的课堂练习中使用Moorea的定居瓷砖。该项目解决了2015-16年El-Niño对法属波利尼西亚Moorea珊瑚繁殖的影响，自2005年以来，人们一直在研究Moorea珊瑚礁LTER。该计划支持的时间序列研究提供了一个独特的历史背景，可以衡量即将到来的El-Niño的生态影响。由于珊瑚白化会对珊瑚繁殖产生负面影响，并且之前的El Niño事件与全球珊瑚招募的减少有关，因此有理由假设Moorea的珊瑚招募将在明年发生规模（即密度下降）和类型（即分类组成）的变化。这些可能性具有重要的意义，因为珊瑚的补充调节了群落对干扰的恢复能力，并调节了未来珊瑚礁发展的轨迹。在这个为期12个月的项目中，将进行一项测量和操作实验，以解决四个假设：(1)El Niño-related海水变暖将抑制珊瑚的招募；(2)变暖将影响珊瑚在定居后的成功；(3)对于Pocillopora，对珊瑚招募的影响将通过密度依赖过程进行调节；(4)由此产生的招募扰动将改变珊瑚群落发展轨迹。这项研究的结果将普遍应用于揭示确定珊瑚礁群落对周期性脉冲干扰（如El Niño事件）的反应的人口统计过程。

This research explores the effects of the 2015-16 El-Niño on coral reefs in French Polynesia where the US National Science Foundation supports a Long-Term Ecological Research site. El Niño brings a diversity of unusual conditions to the Pacific Ocean, but for coral reefs the most important effect is caused by seawater warming during the summer. Bleaching, the process causing corals to lose color and die, is a dramatic example of the negative effects of El Niño on reef corals, but high temperature also has insidious effects through impaired reproduction and poor recruitment of baby corals. As a result, El Niño conditions are likely to be associated with a degraded ability of coral reefs to regrow following disturbances, potentially preventing a full recovery, or favoring substantial changes in the community that develops. This research builds on the unrivalled history of LTER investigations in Moorea to ask how coral recruitment is affected by El Niño, as measured by the number of baby corals arriving to the reef, the number of baby corals that grow, and the kinds of communities that develop as a result of these events. The study involves fieldwork conducted in Moorea by faculty and graduate students, during which settlement tiles will be installed and monitored for baby corals, baby corals will be evaluated for overall "health", and natural and artificial reef surfaces will be quantified for community development. The results of this study will help to understand how marine ecosystems are responding to the spectrum of natural and human-related disturbances to which they exposed, including global climate change, and will improve the capacity to understand in what form coral reefs in US waters and throughout the world will survive the coming century. The project creates unique opportunities for graduate students to work in an international context, where they will conduct research promoting STEM careers, an appreciation of diverse tropical ecosystems, and the role of climate change in modifying ecosystem dynamics. The broader implications of this project will be strengthened by integrating the results into life science curricula at local high schools, in part by utilizing settlement tiles from Moorea in classroom exercises staffed by California State University Northridge graduate students.This project addresses the effects of the 2015-16 El-Niño on coral recruitment in Moorea, French Polynesia, where coral reefs have been studied since 2005 thought the Moorea Coral Reef LTER. Time-series research supported by this program provides a unique historical context against which the ecological effects of the upcoming El-Niño can be gauged. As coral bleaching negatively affects coral reproduction, and previous El Niño events have been associated with globally-depressed coral recruitment, it is reasonably to hypothesize that coral recruitment in Moorea will change in magnitude (i.e., declining density) and type (i.e., taxonomic composition) over the next year. These possibilities have important implications, because coral recruitment mediates community resilience to disturbances, and modulates the trajectories of future reef development. In this 12-month project, a program of mensurative and manipulative experiments will be conducted to addressed four hypotheses: (1) coral recruitment will be depressed following El Niño-related seawater warming, (2) warming will affect post-settlement success of corals, (3) for Pocillopora, the effects on coral recruitment will be modulated through density-dependent processes, and (4) the resulting recruitment perturbations will modify trajectories of coral community development. The results of this research will have general application in revealing the demographic processes determining the response of coral reef communities to recurrent pulse disturbances such as El Niño events.