RAPID: Tracking Recovery from the 2014 Coral Bleaching Event in Hawaiian Waters: Water Quality Gradients, Ecological Factors, and Reef Resilience to Climate Change

珊瑚礁为数百万与珊瑚有关的物种提供栖息地，并支持全球数亿人的基本生计。不幸的是，珊瑚礁对海洋温度升高非常敏感，并且已经显示出热应力事件的重大影响。温暖的天气会导致珊瑚白化，这是一种压力反应，包括生活在珊瑚细胞内的微小藻类的损失，珊瑚依赖这些藻类作为食物。如果没有这些藻类，许多珊瑚就无法生存，因此，随着地球变暖，漂白事件变得越来越普遍，全球范围内的珊瑚礁可能会减少。这个项目将进一步了解夏威夷主要岛屿海岸线上不同的珊瑚是如何应对和从白化中恢复过来的（通过重新获得共生藻类）。这些珊瑚礁从2014年夏末开始经历了严重的白化事件。该项目将记录不同种类珊瑚的白化程度和死亡率，并利用各种珊瑚健康测量方法跟踪个别珊瑚的恢复情况。通过研究水质不同的珊瑚礁，该研究将检验这样一种观点，即受到更大陆地污染的珊瑚礁遭受更广泛的白化，也更不可能从白化中恢复过来。该项目还将使用分子方法来识别和比较具有更强抗白化能力的珊瑚基因。这项研究将解决有关珊瑚白化的基本科学问题，但也将产生必要的数据，以衡量管理者和决策者如何以及是否可以通过改善沿海水质来提高珊瑚礁的恢复能力。该多学科项目将为一名研究生和一名博士后提供资金支持和培训。通过研究人员与当地社区教育项目的持续合作，科学成果将转化为K-12学生、高等教育学员和公众的材料。夏威夷群岛的珊瑚礁目前正在经历严重的白化事件，这对美国水域最大的珊瑚礁栖息地的完整性构成了重大威胁，超过了1996年夏威夷有记录的唯一一次重大白化事件。本研究将记录这一事件的异质性，跟踪珊瑚礁和群落规模从白化中恢复，确定驱动群落之间适应性差异的因素，并在近岸水质的背景下评估珊瑚礁敏感性和恢复力的相关性，以此作为了解陆地压力源对珊瑚抵抗和从白化中恢复能力的影响的一种手段。本研究的主要目标是：(1)记录夏威夷珊瑚对2014年温度异常的空间和分类响应模式；(2)检验水质与珊瑚礁恢复力之间的联系；(3)确定白化反应和恢复异质性的遗传和环境因素。研究人员将部署数据记录仪，并定期采集水样，记录温度、光照（PAR）、沉积物和营养物质浓度、pH值和碱度，在每个地点进行定期视频样带，以捕捉物种和基因型对高温异常的反应和恢复的特异性差异，反复分析单独标记的珊瑚群落在白化事件和恢复期间的生理状态。表征珊瑚全息生物基因组和微生物群落组成。

Corals reefs provide habitat for millions of coral-associated species and support the basic livelihoods of hundreds of millions of people globally. Unfortunately, coral reefs are very sensitive to elevated ocean temperatures and are already showing major impacts from thermal stress events. Warm weather can cause coral bleaching, a stress response that involves the loss of the microscopic algae that live inside coral cells and that corals depend on for food. Without these algae, many corals cannot survive such that, as bleaching events become more common on a warming Earth, coral reefs may decline worldwide. This project will further the understanding of how different corals respond to and recover from bleaching (by re-gaining their symbiotic algae) along the coastline of the main Hawaiian Islands. These coral reefs experience a severe bleaching event that started in late summer 2014. This project will document the extent of bleaching and mortality among different species of corals as well as track the recovery of individual corals using a variety of measurements of coral health. By studying reefs that differ in water quality, the research will examine the idea that coral reefs exposed to greater land-based pollution suffer more extensive bleaching and are also less likely to recover from bleaching. The project will also use molecular methods to identify and compare coral genes that confer greater resistance to bleaching. The research will address basic scientific questions about coral bleaching but will also generate data necessary to gauge how and if managers and decision makers can increase coral reef resilience through improvements in coastal water quality. This multi-disciplinary project will provide financial support and training for one graduate student and one postdoctoral researcher. The scientific results will be translated to material for K-12 students, higher education trainees, and the public through the researchers ongoing relationships with local community education programs. Coral reefs of the Hawaiian Islands are currently experiencing a severe bleaching event that poses a substantial threat to the integrity of the largest area of coral reef habitat in US waters, exceeding levels recorded in 1996 during the only major bleaching event previously documented for Hawaii. This study will document the heterogeneity of this event, follow both reef and colony-scale recovery from bleaching, identify the factors driving fitness differences between colonies, and evaluate the correlates of reef sensitivity and resilience against the backdrop of nearshore water quality as a means to understand the impacts of land-based stressors on the abilities of corals to resist and recover from bleaching. The study will focus on the goals of: (1) documenting the spatial and taxonomic patterns of coral responses to the 2014 temperature anomaly in Hawaii; (2) testing the links between water quality and reef resilience; and (3) identifying genetic and environmental factors responsible for heterogeneity in bleaching response and recovery. The researchers will deploy data loggers and take scheduled water samples to record temperature, light (PAR), sediment and nutrient concentrations, pH and alkalinity, conduct periodic video transects at each site to capture species- and genotype-specific differences in response and recovery to the high temperature anomaly, repeatedly assay the physiological state of individually tagged coral colonies during the bleaching event and recovery, and characterize coral holobiont genomes and microbial community composition.