Cascading interactions of herbivore loss and nutrient enrichment on coral reef macroalgae, corals, and microbial dynamics

草食动物损失和营养富集对珊瑚礁大型藻类、珊瑚和微生物动态的级联相互作用

• 批准号: 1130786
• 负责人: Deron Burkepile
• 金额: $ 82.28万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1130786&HistoricalAwards=false
• 关键词: Cascading; interactions; herbivore; loss; nutrient; Cascading; interactions; herbivore; loss; nutrient

Coral reefs in the Caribbean Sea are undergoing unprecedented declines in coral cover due in large part to climate change, pollution, and reductions in fish biodiversity and abundance. Macroalgae have become abundant on reefs, probably due to decreases in herbivory (e.g., through overfishing) and increases in anthropogenic inputs of nutrients. The spread of macroalgae has negative feedbacks on reef recovery because algae are often superior competitors and suppress growth of both adult and juvenile corals. A majority of reef studies to date have focused on how stressors affect macroorganisms, while relatively few have investigated how these stressors and the resultant algal-dominated states affect microorganisms. Yet, coral reef-associated microbes play significant roles in coral reef ecosystems through biogeochemical cycling and disease. Since microbes are important mutualists of corals as well as potential pathogens, it is important to understand the mechanisms that control their taxonomic and functional diversity.The goal of this proposal is to quantify how alterations of top-down (removal of herbivorous fish) and bottom-up (inorganic nutrient addition) forces alter macrobial as well as microbial dynamics on coral reefs in order to understand the mechanisms that reinforce coral-depauperate reef systems. This work asks two main questions:Q1. How do nutrient enrichment and herbivore removal interact to affect benthic algal abundance, coral-algal interactions, and coral survivorship and growth?Q2. How do nutrient enrichment and herbivore removal affect bacterial abundance, taxonomic diversity, and functional diversity on and within corals?The proposed research will directly and empirically address many of the current hypotheses about how bottom-up and top-down forces alter reef dynamics. The PIs will investigate: (1) the impact of multiple stressors over several years; (2) impacts on multiple levels of biological organization (from fishes to algae to microbes); and (3) the mechanisms underlying changes in algal-coral microbe interactions. Significantly, the approach will provide the statistical power necessary to distinguish between seasonal- and stress-induced changes in macro- and microbial diversity. The proposed work is a unique combination of experimental ecology and microbiology that will improve our ability to evaluate global threats to reefs. Training will include a postdoctoral researcher, a graduate student, and two undergraduates in the fields of marine ecology, microbial symbiosis, and molecular biology. The project will also provide research opportunities for undergraduate minority students, since FIU is one of the largest minority and urban-serving institutions in the US, with over 70% of its students from under-represented groups in science (59% Hispanic, 13% Black, 4% Asian; 56% female). The PIs are also committed to strong outreach programs outside their university at both the local and national levels. For example, they have established a monthly science café ("Eat, Think, and Be Merry!") at an independent Miami bookstore to provide a casual environment for the public to come together with local scientists to learn about and discuss science and conservation topics that impact Florida waters. They are also collaborating with Symbio Studios to produce videos on coral reef ecosystems for their educational series for Houghton Mifflin Harcourt's Science Fusion programs.

加勒比海的珊瑚礁覆盖了珊瑚覆盖的前所未有的下降，这在很大程度上是由于气候变化，污染和鱼类生物多样性和抽象的减少。大藻类在珊瑚礁上变得丰富，可能是由于食草动物的减少（例如，通过过度捕获）以及营养成分人为输入的增加所致。大型藻类的传播对礁石恢复具有负反馈，因为藻类通常是优越的竞争者，并抑制了成人和少年珊瑚的生长。迄今为止，大多数珊瑚礁研究都集中在压力源如何影响宏观生物上，而相对较少的人研究了这些压力源和由此产生的藻类主导状态如何影响微生物。然而，珊瑚礁相关的微生物通过生物地球化学循环和疾病在珊瑚礁生态系统中起着重要作用。 Since microbes are important mutualists of corals as well as potential pathogens, it is important to Understand the mechanisms that control their taxonomic and functional diversity.The goal of this proposal is to quantify how alterations of top-down (removal of herbivorous fish) and bottom-up (inorganic nutrient addition) forces alter macrobial as well as microbial dynamics on coral reefs in order to understand the mechanisms that reinforce珊瑚侵占礁系统。这项工作提出了两个主要问题：Q1。营养富集和草食动物如何消除相互作用以影响底栖藻类抽象，珊瑚 - 阿尔加尔相互作用以及珊瑚生存和生长？Q2。养分富集和食草动物的去除如何影响细菌的丰度，分类学多样性和珊瑚内部和内部的功能多样性？拟议的研究将直接和经验地从经验上解决许多有关自下而上和自上而下力量如何改变礁石动态的当前许多假设。 PI将调查：（1）多年来多种压力源的影响； （2）对多个生物组织的影响（从鱼类到藻类再到微生物）； （3）藻类微生物相互作用的改变的机制。值得注意的是，该方法将提供区分季节性和压力引起的宏观和微生物多样性变化所需的统计能力。拟议的工作是实验生态学和微生物学的独特组合，它将提高我们评估全球对珊瑚礁威胁的能力。培训将包括一名博士后研究人员，一名研究生以及海洋生态学，微生物共生和分子生物学领域的两个本科生。由于FIU是美国最大的少数民族和城市服务机构之一，该项目还将为本科少数群体学生提供研究机会，其中超过70％的学生来自科学领域的代表性不足（59％的西班牙裔，13％，黑人13％，4％的亚洲人，亚洲女性； 56％的女性）。 PI还致力于在本地和国家一级的大学外面进行强大的外展计划。例如，他们在一家独立的迈阿密书店建立了一个每月的科学咖啡馆（“吃，思考和快乐！”），为公众提供了一个休闲的环境，让公众与当地科学家一起学习和讨论影响佛罗里达水域的科学和保护主题。他们还与Symbio Studios合作，为霍顿·米夫林·哈科特（Houghton Mifflin Harcourt）的科学融合计划制作了珊瑚礁生态系统上的视频。