DISSERTATION RESEARCH: Do interactions between ultraviolet radiation and dissolved organic carbon modulate disease in aquatic systems?

环境变化通过改变栖息地的物理特征来改变生态系统，从而影响哪些生物体可以在特定环境中茁壮成长。在这个研究生项目中，研究将解决中西部湖泊变暗的水对常见微型甲壳动物疾病流行的影响。湖泊变暗的发生是由于增加的降水和风暴的严重性，导致植物碎屑流入湖泊。湖泊营养水平和各种波长的光对水中的渗透都受到变暗过程的影响。被称为水蚤的常见小型甲壳类动物可以被某些真菌和/或细菌寄生。 本项目将研究湖泊变暗影响这些寄生虫相互作用的机制。 它将提供深入了解如何改变环境因素可以影响湖泊社区的疾病，也将涉及当地学生在中南部印第安纳州的研究和实地考察。为了量化湖泊变暗如何影响湖泊疾病动态，对于这个博士论文改进补助金，研究生将通过两种处理操纵湖泊围栏的黑暗：阴影和添加溶解有机物。然后，学生将与当地社区成员（水蚤宿主，其他浮游生物和无脊椎动物捕食者）和寄生虫感染的主机种子外壳。在为期十周的实验过程中，将测量非生物栖息地变量（例如温度、pH值、氧气水平）、群落结构和疾病水平，并与没有遮光或添加溶解有机物的对照围栏进行比较。由于湖泊变暗预计将直接或间接地影响所有湖泊群落成员，因此重要的是要观察和量化这些环境因素对宿主，病原体，捕食者，生产者，分解者和物理栖息地结构的影响。通过测量不同处理中群落的差异，我们将能够梳理出湖泊变暗影响疾病的机制。

Environmental change alters ecosystems by changing the physical characteristics of a habitat, affecting which organisms can thrive in a given environment. In this graduate student project, research will address the impacts of darkening water in Midwestern lakes on the prevalence of disease in a common miniature crustacean. Lake darkening occurs due to increases in input of plant debris washing into lakes as a result of increased precipitation and storm severity. Lake nutrient levels and the penetration of various wavelengths of light into the water are both affected by the darkening process. The common miniature crustacean known as Daphnia can be parasitized by certain fungi and/or bacteria. This project will examine the mechanisms by which lake darkening can affect these parasitic interactions. It will provide insight into how altering environmental factors can influence disease in lake communities, and will also involve local students in research and fieldwork in south-central Indiana.In order to quantify how lake darkening affects disease dynamics in lakes, for this Doctoral Dissertation Improvement grant, the graduate student will manipulate the darkness of lake enclosures through two treatments: shading and addition of dissolved organic matter. The student will then seed enclosures with local community members (Daphnia hosts, other plankton, and invertebrate predators) and parasite-infected hosts. Abiotic habitat variables (e.g. temperature, pH, oxygen levels), community structure, and disease levels will be measured throughout the course of the ten-week experiment and compared to control enclosures without shading or added dissolved organic matter. Since lake darkening is expected to affect all lake community members either directly or indirectly, it is important to observe and quantify effects of these environmental factors on hosts, disease agents, predators, producers, decomposers, and physical habitat structure. By measuring differences in communities in the different treatments, we will be able to tease apart the mechanisms by which lake darkening affects disease.