CAREER: Fish-derived nutrients in a coral reef ecosystem - impacts on benthic communities and importance for coral restoration

职业：珊瑚礁生态系统中鱼类来源的营养物质 - 对底栖群落的影响以及对珊瑚恢复的重要性

• 批准号: 1547952
• 负责人: Deron Burkepile
• 金额: $ 83.13万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1547952&HistoricalAwards=false
• 关键词: CAREER; Fish; derived; nutrients; coral

Coral reefs are currently imperiled from a variety of human-induced threats from climate change, coral diseases, overexploitation of important fish species, and enrichment with excessive amounts of nutrients. These threats can result in the decline in corals and fishes and the rise in seaweeds, turning coral reefs into seaweed reefs. One important aspect of understanding how human-mediated changes impact the ecology of reefs is to understand how fishes impact important nutrient cycles on reefs. The investigators prior research suggests that fishes may be one of the most important sources of nitrogen and phosphorus on reefs via their daily excretions. These fish-derived nutrients may help corals grow faster but could also help seaweeds grow faster if corals are killed by other processes such as climate change or disease. However, nutrients from human-derived sources such as runoff from agriculture or sewage discharge can be harmful to corals as these nutrients are often of different types than those in fish excretions. The investigator seeks to understand how the different effects of fish-derived vs. human-derived nutrients impact coral growth, seaweed growth, and, ultimately, the health of coral reef ecosystems. This research will also facilitate a number of training and outreach opportunities including: (1) training graduate and undergraduate students, (2) creating a partnership between FIU and MAST@FIU, a new science and technology magnet high school, to educate underrepresented minorities in marine biology, (3) taking marine science to the masses with widely distributed videos, and (4) creating a citizen science initiative that will get interested marine biology students involved with helping to monitor some of the field experiments. Further, this work will generate much needed information on the science of coral reef restoration. Restoration of reefs is a growing field but many restoration efforts have little solid grounding in understanding the ecological processes that keep reefs healthy. Thus, this work will be able to make significant contribution to educating managers and restoration practitioners as to the processes that can help facilitate successful restoration efforts.This research will address fundamental and untested questions of how nutrient excretion by fishes impacts coral reef communities. Prior data suggest that the ecology of reefs is critically linked to the role of fishes as providers of limiting nutrients since fishes are one of, if not the most important, sources of N on reefs. This research is not only unique in its scope but also timely due to the global threats to reefs. As overfishing removes important fishes (and their role as nutrient providers) and anthropogenic nutrient loading increases the abundance of potentially harmful nutrients, the nutrient regimes on reefs may be changing for the worse. The goal of this project is to quantify how nutrients from fish excretion impact coral reef community structure and how this effect varies across environmental context. Specifically, the investigator outlines research to focus on three general sets of objectives that will be approached on reefs in the Florida Keys, USA: (1) Assess how fish-derived nutrients influence benthic community structure and coral growth and health both across and within reefs and how this influence varies with abiotic context, (2) Test how the physiology and growth of individual corals and algae respond to the different nutrient sources in fish excretion vs. anthropogenic nutrient loading, and (3) Examine how fish-derived nutrients impact coral restoration and how to design restoration programs to take advantage of important of fish-derived nutrients for coral growth. These questions will be addressed with: (1) a field monitoring program (Objective 1), (2) mechanistic nutrient enrichment experiments (Objective 2), and (3) coral restoration experiments (Objective 3).

目前，珊瑚礁正面临气候变化、珊瑚疾病、重要鱼类过度捕捞以及营养物质过量富集等各种人为威胁。这些威胁可能导致珊瑚和鱼类数量减少以及海藻数量增加，从而将珊瑚礁变成海藻礁。了解人类介导的变化如何影响珊瑚礁生态的一个重要方面是了解鱼类如何影响珊瑚礁的重要营养循环。研究人员之前的研究表明，鱼类通过其日常排泄物可能是珊瑚礁上氮和磷的最重要来源之一。这些来自鱼类的营养物质可能有助于珊瑚生长得更快，但如果珊瑚因气候变化或疾病等其他过程而死亡，也可能有助于海藻生长得更快。然而，来自人类来源的营养物质（例如农业径流或污水排放）可能对珊瑚有害，因为这些营养物质的类型通常与鱼类排泄物中的不同。研究人员试图了解鱼类和人类营养物质的不同影响如何影响珊瑚生长、海藻生长，并最终影响珊瑚礁生态系统的健康。这项研究还将促进许多培训和外展机会，包括：(1) 培训研究生和本科生，(2) 在 FIU 和 MAST@FIU（一所新的科技磁铁高中）之间建立合作伙伴关系，以教育代表性不足的少数族裔海洋生物学，（3）通过广泛传播的视频将海洋科学带给大众，以及（4）创建一项公民科学倡议，让感兴趣的海洋生物学学生参与帮助监测一些现场实验。此外，这项工作将产生有关珊瑚礁恢复科学的急需信息。珊瑚礁恢复是一个不断发展的领域，但许多恢复工作在理解保持珊瑚礁健康的生态过程方面缺乏坚实的基础。因此，这项工作将能够为教育管理者和恢复从业者做出重大贡献，让他们了解有助于促进成功恢复工作的过程。这项研究将解决鱼类营养物排泄如何影响珊瑚礁群落的基本且未经测试的问题。先前的数据表明，珊瑚礁的生态与鱼类作为限制性营养物质提供者的作用密切相关，因为鱼类即使不是最重要的氮源，也是珊瑚礁上的氮源之一。这项研究不仅在范围上是独一无二的，而且由于全球珊瑚礁面临的威胁而显得非常及时。由于过度捕捞导致重要鱼类（及其作为营养提供者的作用）消失，而人为营养负荷增加了潜在有害营养物质的丰度，珊瑚礁上的营养状况可能会变得更糟。该项目的目标是量化鱼类排泄物中的营养物质如何影响珊瑚礁群落结构以及这种影响在不同环境背景下如何变化。具体来说，研究人员概述了将在美国佛罗里达群岛的珊瑚礁上实现的三组总体目标的研究：（1）评估鱼类来源的营养物质如何影响珊瑚礁内外的底栖群落结构以及珊瑚生长和健康以及这种影响如何随非生物环境而变化，(2) 测试个体珊瑚和藻类的生理和生长如何对鱼类排泄与人为营养负荷中的不同营养源做出反应，以及 (3) 检查如何鱼源营养物质影响珊瑚恢复，以及如何设计恢复计划以利用鱼源营养物质促进珊瑚生长。这些问题将通过以下方式解决：(1) 现场监测计划（目标 1），(2) 机械营养富集实验（目标 2），以及 (3) 珊瑚恢复实验（目标 3）。