The Role of Benthic Resting Stages In Phytoplankton Seasonal Periodicity and Responses to Ecosystem Perturbations

9318402桑德格伦这项研究将提供一项严格的捕食测试，将其作为确定猎物生物地理的主要因素。PI将测试许多藻类的生物地理分布的可能性，例如金藻鞭毛虫，主要是由于捕食者-猎物与食草性浮游动物Daphnia的强烈相互作用的结果。金藻分布与湖泊生产力呈显著负相关。虽然水蚤已被确定为湖泊食物网中的主要食草动物，但此前并未强调它会影响湖泊中金藻的分布。另一种假设，例如藻类之间对营养的竞争，也将被考虑。来自这些假设的预测将通过实验室和现场实验的组合、藻类物种之间的竞争建模以及藻类、水蚤和湖泊生产力的经验分布抽样来验证。这项研究很重要，因为它将检验一个新的和重要的假设，即物种的生物地理分布和丰度对捕食者密度和栖息地生产力的反应。由于一些藻类水华会导致水库水质变差，这些结果将对评估影响湖泊水质的生物因素具有重要意义。***

9318402 Sandgren This research will provide a rigorous test of predation as a primary factor in determining prey biogeography. The PI's will test the possibility that the biogeographical distribution of many groups of algae, such as chrysophyte flagellates, is primarily the result of strong predator-prey interactions with the herbivorous zooplankton, Daphnia. There is a strong negative correlation between the distribution of Chrysophyte algae and lake productivity. While Daphnia has been identified as a dominant herbivore in lake food webs, it has not been previously emphasized as affecting the distribution of chrysophytes among lakes. Alternative hypotheses, such as competition between algae for nutrients, will be considered, as well. Predictions from these hypotheses will be tested with a combination of laboratory and field experiments, modeling competition among algae species, and sampling empirical distribution of algae, Daphnia, and lake productivity. %%% This research is important because it will test a novel and important hypothesis regarding the biogeographic distribution and abundance of species in response to predator densities and habitat productivity. Because some algal blooms can cause poor water quality in reservoirs, these results will have important implications for assessing the biotic factors that contribute to lake water quality. ***