RAPID: Immediate and Subsequent Effects of Coral Bleaching on Fore Reef Community Metabolism

RAPID：珊瑚白化对前礁群落代谢的直接和后续影响

• 批准号: 1946866
• 负责人: Robert Carpenter
• 金额: $ 17.61万
• 依托单位: The University Corporation, Northridge
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946866&HistoricalAwards=false
• 关键词: RAPID; Immediate; Subsequent; Effects; Coral

Coral reefs are among the most productive marine ecosystems that provide important ecosystem services such as food resources and coastal protection. Coral reefs are constructed primarily by calcified invertebrates (corals), and they create habitat for a large diversity of associated organisms, including many fish species. Corals have a narrow range of temperature tolerance and when temperature exceeds a threshold, they "bleach" releasing their primary producing symbiotic algae. Corals can recover from bleaching but a more frequent outcome is mortality. This has the potential to drastically change of the cycle of organic and inorganic carbon on the reef, however we know little about how these processes are affected. Beginning in April 2019, there was a moderately severe bleaching event on the coral reefs of Moorea, French Polynesia, the site of the only NSF-funded LTER program focused on coral reefs. This project leverages knowledge from the MCR-LTER program and measures how the recent coral bleaching affects both reef primary production and calcification both immediately (after 1 month) and over a year- long period at two depths on the fore reef. These are the first measurements of how coral bleaching affects coral fore reef function. The project trains personnel (postdoc, technician), involve graduate students, and results are disseminated to several educational levels (in both the US and French Polynesia) and to island resource managers in Moorea.This project addresses how a recent coral bleaching event in Moorea, French Polynesia affects coral fore reef function (primary production [NEP], respiration [R], calcification [NEC]) over time at two depths. We know that coral reef composition can be affected greatly by coral bleaching. However, we know little about how coral reef function is affected. This project measures coral reef function at 3 time points following the bleaching at 6 sites around the island and at both 10 and 17-m depths. The investigators use a gradient flux approach that quantifies vertical gradients in scalar quantities combined with measures of vertical diffusivity to calculate rates of flux to and from the benthos. They measure NEP/R from oxygen flux and NEC from pH and total alkalinity (DIC flux). All rates are normalized to photosynthetically active radiation to account for temporal variation in light. The investigators predict that NEP/R will not change or might even increase post-bleaching but that NEC decreases in proportion to coral mortality. Coral reef community structure for the metabolic "footprint" at each site/depth combination is quantified using photo-mosaics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

珊瑚礁是最具生产力的海洋生态系统之一，提供重要的生态系统服务，如食物资源和沿海保护。珊瑚礁主要由钙化的无脊椎动物（珊瑚）构成，它们为包括许多鱼类在内的各种相关生物创造了栖息地。珊瑚的温度耐受范围很窄，当温度超过阈值时，它们会“漂白”，释放出主要的共生藻类。珊瑚可以从漂白中恢复，但更常见的结果是死亡。这有可能彻底改变珊瑚礁上有机和无机碳的循环，但我们对这些过程如何受到影响知之甚少。从2019年4月开始，法属波利尼西亚莫雷阿岛的珊瑚礁发生了中度严重的漂白事件，这是唯一一个由NSF资助的LTER项目，重点关注珊瑚礁。该项目利用MCR-LTER计划的知识，并测量最近的珊瑚漂白如何立即（1个月后）和在前礁两个深度长达一年的时间内影响珊瑚礁初级生产和钙化。这是第一次测量珊瑚漂白如何影响珊瑚礁功能。该项目培训人员（博士后、技术员），让研究生参与，并将结果传播到几个教育层次（在美国和法属波利尼西亚）和莫雷阿岛的岛屿资源管理人员，该项目讨论了法属波利尼西亚莫雷阿岛最近的珊瑚漂白事件如何影响珊瑚礁功能（初级生产[NEP]、呼吸[R]、钙化[NEC]）。我们知道，珊瑚礁的组成可能会受到珊瑚白化的严重影响。然而，我们对珊瑚礁的功能如何受到影响知之甚少。该项目在岛屿周围6个地点10米和17米深的珊瑚礁白化后的3个时间点测量珊瑚礁的功能。调查人员采用梯度通量方法，以标量量化垂直梯度，并结合垂直扩散率的测量，计算进出底栖生物的通量率。他们从氧通量测量NEP/R，从pH和总碱度（DIC通量）测量NEC。所有速率均归一化为光合有效辐射，以说明光的时间变化。研究人员预测，NEP/R不会改变，甚至可能增加漂白后，但NEC下降成比例的珊瑚死亡率。珊瑚礁群落结构的代谢“足迹”在每个网站/深度组合使用photo-mosaics.This奖项量化反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。