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，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漂白，这是一种压力反应，涉及生活在珊瑚细胞内的微小藻类的丧失，珊瑚依赖这些藻类作为食物。如果没有这些藻类，许多珊瑚就无法存活，因此，随着变暖的地球上白化事件变得越来越常见，珊瑚礁可能会在全球范围内减少。该项目将进一步了解不同的珊瑚如何应对夏威夷群岛主要海岸线上的漂白(通过重新获得共生藻类)并从中恢复。这些珊瑚礁经历了从2014年夏末开始的严重白化事件。该项目将记录不同种类珊瑚的漂白和死亡程度，并使用各种珊瑚健康衡量标准跟踪个别珊瑚的恢复情况。通过研究水质不同的珊瑚礁，这项研究将检验这样一种观点，即暴露在陆地污染更严重的珊瑚礁会遭受更广泛的漂白，也不太可能从漂白中恢复。该项目还将使用分子方法来识别和比较对漂白具有更强抵抗力的珊瑚基因。这项研究将解决有关珊瑚漂白的基本科学问题，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能够通过改善沿海水质来提高珊瑚礁的弹性。这个多学科项目将为一名研究生和一名博士后研究员提供资金支持和培训。研究人员将通过与当地社区教育项目的持续联系，将科学成果转化为供K-12学生、高等教育实习生和公众使用的材料。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严重威胁，超过了1996年夏威夷记录的唯一重大白化事件期间的水平。这项研究将记录这一事件的异质性，跟踪珊瑚礁和群落规模的白化恢复，确定导致群落之间适应性差异的因素，并评估近岸水质背景下珊瑚礁敏感性和弹性的相关性，以此作为了解陆地应激源对珊瑚抵抗白化和从白化中恢复能力的影响的一种手段。这项研究将侧重于以下目标：(1)记录珊瑚对2014年夏威夷温度异常的反应的空间和分类模式；(2)测试水质与珊瑚礁弹性之间的联系；以及(3)确定导致漂白反应和恢复的异质性的遗传和环境因素。研究人员将部署数据记录器并采集预定的水样，以记录温度、光照(PAR)、沉积物和营养物质浓度、pH和碱度，在每个地点进行定期视频横断面，以捕捉物种和基因特定的差异，对高温异常的反应和恢复，重复分析漂白事件和恢复期间单独标记的珊瑚群体的生理状态，并表征珊瑚全硫酸盐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.