CAREER: Linking genetic diversity, population density, and disease prevalence in seagrass and oyster ecosystems

海洋中的疾病爆发正在增加，造成具有重要生态意义的海洋物种的损失，但导致这些疾病爆发的因素尚未得到很好的了解。这个为期5年的CAREER项目将研究两种海洋基础物种的疾病患病率和强度-海草Zostera marina和东方牡蛎Crassostrea virginica。更具体地说，将探讨宿主与疾病的关系，以了解宿主物种的遗传多样性和种群密度如何影响疾病传播和风险。这项工作将配对大规模的实验恢复和小规模的现场实验，以检查跨多个空间尺度的疾病-宿主关系。比较两个沿海系统的模式和机制将为确定多样性-密度-疾病关系的普遍性提供重要的第一步。为了提高这项工作的广泛影响和效用，实验将与修复从业者合作进行，并以从主要利益相关者团体获得的知识为指导。该项目将支持一名早期职业女性研究员和多名研究生和本科生的发展。学生将接受最先进的分子技术培训，以量化牡蛎和海草寄生虫。调查和实验工作的主要发现将被纳入保护生物学、海洋生物学和疾病生态学的本科课程。最后，这些课程的学生将帮助开发社会生态调查和相互学习游戏，通过一系列研讨会促进利益相关者之间的知识转移。宿主遗传多样性与疾病动态之间的关系是复杂的。在某些情况下，被称为稀释效应的多样性减少了疾病传播和风险。然而，当多样性增加感染风险时，也会出现相反的关系，即放大效应。即使多样性直接降低疾病风险，多样性对宿主密度的同时积极影响也可能通过增加感染和未感染个体之间的疾病传播而导致放大。将利用海草（Zostera marina）和牡蛎（Crassostrea virginica）的大规模野外恢复来测试寄主遗传多样性对寄主种群密度和疾病流行/强度的影响。另外的现场实验将独立操纵宿主遗传多样性和密度，研究导致稀释或扩增的机制。在两种海洋基础物种（一种是无性系植物，另一种是非无性系动物）中进行类似的操作将有助于确定多样性-密度-疾病关系中的共性。此外，项目科学家、学生和利益相关者之间的合作将加强跨学科培训，并有助于促进信息交流，以改善管理和恢复工作。作为这些工作的一部分，有针对性的调查将用于记录管理者和恢复从业者对遗传多样性及其在生态恢复力和恢复中的作用的看法和态度。

Disease outbreaks in the ocean are increasing, causing losses of ecologically important marine species, but the factors contributing to these outbreaks are not well understood. This 5-year CAREER project will study disease prevalence and intensity in two marine foundation species - the seagrass Zostera marina and the Eastern oyster Crassostrea virginica. More specifically, host-disease relationships will be explored to understand how genetic diversity and population density of the host species impacts disease transmission and risk. This work will pair large-scale experimental restorations and smaller-scale field experiments to examine disease-host relationships across multiple spatial scales. Comparisons of patterns and mechanisms across the two coastal systems will provide an important first step towards identifying generalities in the diversity-density-disease relationship. To enhance the broader impacts and utility of this work, the experiments will be conducted in collaboration with restoration practitioners and guided by knowledge ascertained from key stakeholder groups. The project will support the development of an early career female researcher and multiple graduate and undergraduate students. Students will be trained in state-of-the-art molecular techniques to quantify oyster and seagrass parasites. Key findings from the surveys and experimental work will be incorporated into undergraduate courses focused on Conservation Biology, Marine Biology, and Disease Ecology. Finally, students in these courses will help develop social-ecological surveys and mutual learning games to stimulate knowledge transfer with stakeholders through a series of workshops.The relationship between host genetic diversity and disease dynamics is complex. In some cases, known as a dilution effect, diversity reduces disease transmission and risk. However, the opposite relationship, known as the amplification effect, can also occur when diversity increases the risk of infection. Even if diversity directly reduces disease risk, simultaneous positive effects of diversity on host density could lead to amplification by increasing disease transmission between infected and uninfected individuals. Large-scale field restorations of seagrasses (Zostera marina) and oysters (Crassostrea virginica) will be utilized to test the effects of host genetic diversity on host population density and disease prevalence/intensity. Additional field experiments independently manipulating host genetic diversity and density will examine the mechanisms leading to dilution or amplification. Conducting similar manipulations in two marine foundation species - one a clonal plant and the other a non-clonal animal - will help identify commonalities in the diversity-density-disease relationship. Further, collaborations among project scientists, students, and stakeholders will enhance interdisciplinary training and help facilitate the exchange of information to improve management and restoration efforts. As part of these efforts, targeted surveys will be used to document the perceptions and attitudes of managers and restoration practitioners regarding genetic diversity and its role in ecological resilience and restoration.