Collaborative Research: Physical Limnology for the Parasite Ecologist

传染病如何影响种群动态和群落相互作用是水生生态学的一个未充分研究的方面。本文主要研究了一种常见的微寄生真菌与水蚤寄主之间的生态相互作用，以及这种相互作用对共生的浮游动物及其猎物浮游植物的影响。pi正在合并三个学科（群落生态学、自然湖沼学和流行病学模型）来解释宿主-寄生虫动态的时空模式。在模拟的同时，还进行了比较和操纵实验，以便在广泛的湖泊中将物理混合与宿主-寄生虫种群动态结合起来。生态和物理混合过程的耦合通常是一个重要的目标，因为大多数水生微寄生虫不像它们的动物宿主那样游泳。因此，沉积物中寄生虫孢子的下沉和再悬浮可能会限制疾病在湖泊和海洋中的水平传播和传播。这项工作的动机是水蚤自然种群中疾病暴发的季节性时间，以及在不同形态和风混合潜力的湖泊中流行病严重程度的实质性变化。pi正在研究单个湖泊中宿主-寄生虫相互作用的时间动态，以及控制多个湖泊中宿主-寄生虫结果的更广泛的物理-生物过程。正在利用实验室和实地研究来参数化标准宿主-寄生虫模型，并得出预测，特别是阈值效应，并在整个水柱操纵实验中进行测试。湖泊热结构、底部剪应力和湍流速度尺度的测量，以及孢子浓度的变化，使模型开发能够预测湖泊沉积物中的孢子悬浮和再悬浮。将物理混合模型的输出与模型耦合，以预测流行病爆发的可能性。在大型围场中，寄主和寄生虫的多代动力学正在被探索，以检查一个水蚤种群内感染对其同系物及其浮游植物猎物的竞争相互作用的间接影响。更广泛的影响：利用这个多湖，水蚤-寄生虫系统，这项合作研究正在解决疾病流行的自然变化的一般现象及其对食物网结构的影响。这项研究汇集了人口和社区生态学、物理湖沼学和建模方面的初级和高级教师。其次，pi是水生生态中病原体作用研究较少的领域。疾病生态学是一个新兴的关注领域，但是尽管有大量证据表明病原体是食物网的重要组成部分，淡水生态学家在很大程度上忽略了它们。第三，采用描述性、比较性和可操控性实验与建模相结合的方法，研究多时空尺度下的疾病生态学。该项目强调培养自然湖沼学、人口模型和群落生态学领域的本科生、研究生和博士后。最后，对物理湖沼学和寄生的研究增强了KBS（一个野外站）周围湖泊的知识基础，并直接有利于在这些系统中开展工作的多个机构的水生生态学家的研究项目。它正在为KBS的K-12教师伙伴关系项目和其他外展活动做出贡献。

How infectious diseases influence population dynamics and community interactions is an understudied aspect of aquatic ecology. This work focuses on the ecological interaction between a common microparasitic fungus and its Daphnia host species, and the consequences to coexisting zooplankton and their phytoplankton prey. The PIs are merging three disciplines (community ecology, physical limnology and epidemiological modeling) to explain spatial and temporal patterns of host-parasite dynamics. Comparative and manipulative experiments are being conducted in parallel with modeling to couple physical mixing with host-parasite population dynamics in a broad set of lakes. The coupling of ecological and physical-mixing processes is a generally important goal since most aquatic microparasites, unlike their animal hosts, do not swim. Hence, sinking and resuspension of parasite spores from the sediment may limit horizontal transmission and spread of diseases in lakes and oceans. This work is motivated by the seasonal timing of disease outbreaks in natural populations of Daphnia and the substantial variability in the severity of epidemics among lakes differing in morphometry and potential for wind mixing. The PIs are examining both the temporal dynamics of host-parasite interactions within single lakes and broader scale physical-biological processes that govern host-parasite outcome among multiple lakes. Laboratory and field studies are being used to parameterize a standard host-parasite model and derive predictions, especially of threshold effects, and tested in whole water-column manipulative experiments. Measurements of lake thermal structure, bottom shear stresses and turbulent velocity scales, in conjunction with changes in spore concentration, are enabling model development to predict spore suspension and resuspension from lake sediments. Output from the physical mixing model are coupled to the model to predict the likelihood of epidemic outbreaks. Multi-generational dynamics of host and parasite are being explored in large enclosures to examine the indirect effects of infection within one Daphnia population on competitive interactions with congeners, and their phytoplankton prey. Broader impacts: Using this multiple-lake, Daphnia-parasite system, this collaborative research is addressing the general phenomenon of natural variation in disease prevalence and its impact on the structure of food webs. This research brings together junior and senior faculty with combined expertise in population and community ecology, physical limnology and modeling. Second, the PIs are a poorly studied area of aquatic ecology, the role of pathogens. Disease ecology is an emerging area of concern, but despite substantial evidence for pathogens as important components of food web, freshwater ecologists have largely ignored them. Third, the study of disease ecology at multiple temporal and spatial scales is being approached with a combination of descriptive, comparative and manipulative experiments with modeling. The project emphasizes training of undergraduates, graduates and a postdoc at the interface of physical limnology, population modeling, and community ecology. Finally, the work on physical limnology and parasitism is enhancing the knowledge base for the lakes around KBS (a field station) and directly benefit the research programs of aquatic ecologists from multiple institutions who conduct their work in these systems. It is contributing to the K-12 teacher partnership project at KBS and to other outreach activities.