Can Coral Reefs in the Central Pacific Survive Ocean Warming? A 2015 El Nino Test

中太平洋的珊瑚礁能否在海洋变暖中生存？

• 批准号: 1605365
• 负责人: Anne Cohen
• 金额: $ 13.55万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1605365&HistoricalAwards=false
• 关键词: Coral; Reefs; Central; Pacific; Survive

This project supports a 7 day expedition to the heart of the central tropical Pacific during a particularly strong El Niño event, arguably one of the strongest on record. The target is Jarvis Island, located in the path of the cool, nutrient-rich Equatorial Under-Current (EUC). As a consequence of its location, Jarvis, a pristine, uninhabited coral reef ecosystem, is characterized by enhanced productivity, high densities of large predatory fish, turtles, corals and other sea life. However, sea surface temperatures on Jarvis are currently 3.9 degrees Celsius higher than normal for this time of year, due to El Niño. This provides investigators with a unique opportunity to examine how a highly productive reef ecosystem responds to ocean warming, and the mechanisms and timescales for recovery. Information will be collected by deploying state-of-the-art instrumentation on the reef, and sampling seawater, particulates, plankton and corals from surface to 150 meters depth. This will be the first expedition to Jarvis Island during a bleaching event. The US Pacific Remote Island Marine National Monument (PRIMNM) was recently expanded as part of a multi-national commitment to protect and preserve vast areas of our ocean and ocean resources for future generations. However, these protections do not shield ocean ecosystems from the impacts of 21st century climate change. The project investigates the potential for simultaneous changes in equatorial ocean circulation to lessen the impacts of the global warming for equatorial reefs. It tests hypotheses that improve understanding of fundamental mechanisms of coral reef resilience to climate change, and the ability to identify such reef systems for inclusion in Protected Area Networks. The cruise supports the training of four PhD students, three of whom are National Science Foundation / National Defense Science and Engineering graduate research fellows, and provide material in support of six PhD theses. Results will be shared at international meetings and workshops, and published in peer-reviewed journals. All data collected and generated from the cruise will be made publicly available via the Biological and Chemical Oceanography Data Management Office.Global climate models project enhanced warming of the central tropical Pacific over this century. By implication, waters bathing five out of the seven coral reef ecosystems protected within the recently expanded PRIMNM, will warm by more than 3 degrees Celsius. This rate of warming far exceeds the known thermal tolerances of reef-building corals, fueling concerns that these reefs may not survive 21st century climate change. However the same models project a concurrent strengthening of the EUC, a projection supported by observations. The EUC carries cool, nutrient-rich waters that upwell on the west sides of the equatorial islands, cooling the reefs and enhancing productivity locally. If the GCM projections are realized, a strengthening EUC could modulate the impact of ocean warming for these reefs by reducing the rate of warming and supporting energetically replete coral communities that survive bleaching. This proposal exploits the current El Niño state of the tropical Pacific to test the following hypotheses: (1) Coral communities bathed in the nutrient-rich, productive waters of the central equatorial Pacific bleach during every El Niño, but mortality is low and as a result, percent live cover remains high. (2) Localized EUC-enhanced productivity supports nutritionally replete coral communities, which metabolize existing lipid reserves to support energetic requirements during bleaching. (3) In addition, equatorial corals adopt a flexible feeding strategy, switching from direct nitrate uptake during nitrogen-rich (greater than 5 micromolar nitrate) La Niña conditions to heterotrophic feeding during nitrogen-"poor" (less than 3 micromolar nitrate) El Niño conditions. We propose that, fueled by exogenous sources, equatorial Pacific coral communities survive bleaching with limited mortality, coral cover remains high and coral growth rates quickly recover. If data generated under this project support our hypotheses, then the combination of oceanographic and political protections could maximize the potential for coral reef survival through the 21st century.

该项目支持在一个特别强大的厄尔尼诺事件中进行7天的探险，以期为热带太平洋中部，这可以说是有记录在案的强者之一。目标是Jarvis Island，位于凉爽，营养丰富的赤道下流（EUC）的路径中。由于其位置，原始的，无人居住的珊瑚礁生态系统Jarvis的特征是生产率提高，高密度的大型掠食性鱼类，乌龟，珊瑚和其他海洋生物的特征。但是，由于厄尔尼诺现象，贾维斯（Jarvis）的海面温度目前比正常情况高3.9摄氏度。这为研究人员提供了一个独特的机会，可以研究高生产力的珊瑚礁生态系统如何响应海洋变暖，以及恢复的机制和时间尺度。将通过在礁石上部署最先进的仪器，并将海水，零件，浮游生物和珊瑚从地面到150米的深度来收集信息。这将是一次漂白活动期间首次前往贾维斯岛的探险。最近，美国太平洋偏远岛海洋国家纪念碑（PRIMNM）作为跨国承诺的一部分，旨在保护和保护我们的海洋和海洋资源的广大承诺。但是，这些保护并不能使海洋生态系统免受21世纪气候变化的影响。该项目调查了同时改变赤道海洋循环的潜力，以减少全球变暖对赤道礁的影响。它测试了假设，即提高对珊瑚礁弹性对气候变化的基本机制的理解，以及识别这种珊瑚礁系统以包含在保护区网络中的能力。巡航支持四名博士学位学生的培训，其中三名是国家科学基金会 /国防科学与工程研究生研究研究员，并提供了支持六个博士学位论文的材料。结果将在国际会议和研讨会上共享，并在同行评审期刊上出版。从巡航中收集和生成的所有数据将通过生物学和化学海洋学数据管理办公室公开获得。全球气候模型在本世纪增强了热带太平洋中部太平洋的变暖。暗示着，在最近扩展的PRIMN中保护的七个珊瑚礁生态系统中，沐浴五个，将温暖3摄氏度。这种变暖的速度远远超过了珊瑚礁珊瑚的已知热公差，这引起了人们对这些礁石可能无法在21世纪气候变化中幸存下来的担忧。然而，同一模型的同时增强了EUC，这是一个预测的观测支持。 EUC携带着凉爽，营养丰富的水，这些水在赤道岛的西侧上升，冷却礁石并在当地提高生产力。如果实现了GCM项目，则加强EUC可以通过降低变暖和支持的速度有效地取代幸存下来漂白的珊瑚群落来调节海洋变暖对这些礁石的影响。 This proposal explores the current El Niño state of the tropical Pacific to test the following hypotheses: (1) Coral communities bathed in the nutrient-rich, productive waters of the central equivalency Pacific bleach (2) Localized EUC-enhanced productivity supports nutritionally replaced coral communities, which metabolize existing lipid reserves to support energy requirements during bleaching. （3）此外，相等的珊瑚采用柔性喂养策略，从富含氮的氮（大于5微甲酯）LaNiña条件下从氮的直接硝酸盐摄取转变为氮气中的异养喂养，“较差”（小于3微摩尔硝酸盐）ElNiounño条件。我们建议，随着外在来源的推动，平等的太平洋珊瑚群落在漂白剂中幸存下来，死亡率有限，珊瑚覆盖率仍然很高，而珊瑚的生长速度迅速恢复。如果该项目下产生的数据支持我们的假设，那么海洋学和政治保护的结合可以最大程度地利用21世纪的珊瑚礁生存的潜力。