CAREER: Small Grazers, Multiple Stressors and the Proliferation of Fungal Disease in Marine Plant Ecosystems

在陆生植物群落中，食草动物对植物真菌病害的促进作用已经研究了世纪。尽管这种相互作用在陆地系统中普遍存在，但直到研究人员最近在盐沼中的工作，才被认为与海洋植物群落的结构有关。通过操纵食草动物和真菌的存在，他证明了蜗牛放牧和随后的活草真菌感染会导致植物生长急剧减少，并且在高食草动物密度下，会破坏冠层。如果食草动物对海洋植物真菌疾病的促进作用不仅限于沼泽地（正如对4种海洋植物生态系统的全球调查的初步数据所表明的那样），那么小型食草动物对植物的叮咬可能对全球海洋植物产生类似的强大但未被发现的控制。此外，由于物理压力通常会降低植物的免疫反应，加强与海洋全球变化相关的多种压力源可能会加剧和破坏这些未经研究的食草动物-疾病-植物相互作用。为了测试这一潜在的关键生态相互作用的全球通用性，本项目将通过跨两大洲的4个生态系统的多地点调查和操作来回答以下问题：1）食草动物促进海洋植物真菌疾病是一种常见但被忽视的相互作用吗？2)食草动物促进的真菌感染对海洋植物生长的影响是什么？3)多重压力如何影响海洋植物真菌病的食草动物促进强度？这项工作代表了我们对海洋生态系统中植物-食草动物相互作用的理解向前迈出了变革性的一步，因为它填补了我们对海洋植物生态系统自上而下控制的理解中100年的知识空白：小型食草动物通常会促进海洋植物中的真菌疾病，这种相互作用会抑制植物生长吗？这种神秘的证据，但强大的机制食草动物调节海洋植物将迫使海洋生态学家重新评估我们的理解自上而下的控制，并导致疾病的动力学在海洋食物网ecology.The后果的广泛整合海洋植物生态系统的健康是深远的人类，因为这些社区提供了许多必要的服务。这项研究的结果将使管理人员能够更好地预测疾病和全球变化对海洋植物系统的影响，并制定有效的保护战略。为了帮助将植物疾病动态纳入海洋生态学和保护，研究人员将：（1）制作关于海洋生态系统中的食物网和疾病的编辑卷，（2）与大自然保护协会密切合作，将研究结果纳入其全球海洋学习交流。此外，综合教育计划将增加学生：（1）了解海洋生态系统中的疾病和食物网动态，（2）考虑海洋科学职业。这一目标将通过班级发展和早期学生接触到实地学习和独立研究来实现。在过去的3年中，调查员在UF组织了一个成功的本科海洋实地课程。他将通过纳入基于食物网疾病-植物相互作用的新讲座和实验室来加强其课程。他将通过吸引优秀的学生，将这种综合教育的努力扩大到高中学生。（童子军）和风险（低年级，出勤率）在动手，实地科学和潜在的职业机会，通过：1）为期两周的实地课程，并提供综合网络支持，2）夏季海洋植物病害研究; 3）2008年在UF发起的海洋研讨会上介绍了结果。该项目的资金由生物海洋学计划，海洋科学教育计划，国际科学与工程美洲项目办公室。

In terrestrial communities, grazer-facilitation of fungal disease in plants has been studied for over a century. Despite the prevalence of this interaction in terrestrial systems, it was not considered relevant to the structure of marine plant communities until the investigator's recent work in salt marshes. By manipulating both grazer and fungal presence, he demonstrated that snail grazing and subsequent fungal infection in live grass led to drastic reductions in plant growth and, at high grazer densities, destruction of canopy. If grazer promotion of fungal disease in marine plants is not limited to marshes (as suggested by preliminary data from a world-wide survey of 4 marine plant ecosystems) then small grazers that take small bites out of plants could be exerting similarly strong, but undetected control over marine plants globally. In addition, since physical stress commonly reduces plant immune responses, intensifying multiple stressors associated with marine global change could intensify and destabilize these unstudied grazer-disease-plant interactions. To test the global generality of this potentially keystone ecological interaction, this project will answer the following questions with a combination of multi-site surveys and manipulations across 4 ecosystems spanning 2 continents: 1) Is grazer facilitation of fungal disease in marine plants a common but overlooked interaction? 2) What is the resultant impact of grazer-facilitated fungal infection on marine plant growth? 3) How do multiple stressors impact the strength of grazer facilitation of fungal disease in marine plants? The work represents a transformative step forward in our understanding of plant-grazer interactions in marine ecosystems as it fills a 100-year intellectual gap in our understanding of top-down control in marine plant ecosystems: Do small grazers commonly facilitate fungal disease in marine plants and does this interaction suppress plant growth?Evidence for this cryptic, yet powerful mechanism of grazer regulation of marine plants will compel marine ecologists to reevaluate our understanding of top-down control and lead to widespread integration of disease dynamics in marine food web ecology.The consequences of marine plant ecosystem health are far-reaching for humans, since these communities provide many essential services. Results from this study will allow managers to better predict effects of disease and global change on marine plant systems and formulate effective strategies for conservation. To help integrate plant disease dynamics into marine ecology and conservation, the investigator will: (1) produce an edited volume on Food Webs and Disease in Marine Ecosystems and (2) work closely with The Nature Conservancy to incorporate findings into their global marine learning exchanges. In addition, an integrated educational plan will increase student: (1) understanding of disease and food web dynamics in marine ecosystems and (2) consideration of marine science careers. This goal will be accomplished through class development and early student exposure to field-based learning and independent research. Over the past 3 years, the investigator has organized a successful undergraduate marine field course at UF. He will enhance its curriculum by incorporating new lectures and laboratories based on food web disease-plant interactions. He will expand this integrated educational effort to high school students by engaging students that are excelling (boy scouts) and at-risk (low grades, attendance) in hands-on, field science and potential career opportunities through: 1) a two-week field class with integrated web support, 2) mentored summer research on marine plant disease and 3) presentation of results at the Marine Symposium initiated at UF in 2008.Funding for this project was provided by the Biological Oceanography Program, Ocean Science Education Program, and Office of International Science and Engineering Americas Program.