Collaborative Research: Organism-environment interactions - impact of cultural eutrophication on Daphnia tracked by genomics, physiology and resurrection ecology

考虑到生物（包括人类）在生态系统过程中发挥的重要作用，令人惊讶的是，很少有研究人为的环境变化如何影响生物进化和适应的方式。在一项为期36个月的计划项目中，pi将使用一种综合方法，包括遗传/基因组学、生理学和“复活生态学”方法，研究培养富营养化（即用磷等营养物质丰富淡水系统）如何影响生物体的进化变化。水蚤（Daphnia pulex）在淡水食物网中扮演着重要角色（即以藻类/细菌为食，以鱼类为食），将作为模式生物。水蚤是此类研究的理想选择，因为它们产生的休眠卵可以在湖泊沉积物中休眠很长一段时间。几十年前的鸡蛋可以被诱导孵化(即。“复活生态”)，并且可以从数百年前的卵子中提取出可存活的DNA。此外，已经对水蚤基因组进行了测序，并采用了遗传/基因组方法（即基因表达）来研究过去一个世纪里富营养化（磷水平）模式的变化如何影响水蚤等生物对生态系统/环境变化的响应。PIs希望发现不同种群的遗传结构和生理机制的明显变化，这些种群是从富营养化历史不同的湖泊中休眠卵库的不同沉积物（时间）层中“复活”的。这项跨学科研究的结果将提供一个很好的例子，说明人为环境变化（通过富营养化）如何影响自然（淡水）生态系统。学术研究人员（如大学）、应用研究人员（如湖泊管理人员）和公众成员（如娱乐用户）应该对这个项目的结果非常感兴趣。教育培训机会将包括美国原住民高中实习生作为研究助理。研究结果将发表在同行评议的期刊上，同时计划向学术界和公众发表演讲。

Given the important role that organisms (including man) play in ecosystem processes, it is surprising that little work has examined how man-made environmental changes affect the way organisms evolve and adapt. In a planned 36-month project, the PIs will use an integrated approach involving genetic/genomic, physiological, and 'resurrection ecology' methods to examine how cultural eutrophication (i.e., enrichment of freshwater systems with nutrients such as phosphorus) influences evolutionary changes in organisms. The waterflea, Daphnia pulex, which plays a major role in freshwater food webs (i.e. it eats algae/bacteria and in turn is fed upon by fish), will serve as the model organism. Daphnia are ideal for such studies because they produce resting eggs that can lay dormant in lake sediments for long periods of time. Decades-old eggs can be induced to hatch (i.e. 'resurrection ecology') and viable DNA can be extracted from eggs that are centuries old. Moreover, the D. pulex genome has been sequenced and genetic/genomic methods (i.e. gene expression) are in place to study how changes in eutrophication (phosphorus-level) patterns over the past century have influenced how an organism like a daphniid can respond to ecosystem/environmental change. The PIs expect to find distinct changes in the genetic structure and physiological mechanisms of different populations 'resurrected' from different sediment (time) layers in the resting egg bank from lakes that differ in eutrophication history. Results from this cross-disciplinary study will provide an excellent example of how man-made environmental changes (via eutrophication) influence natural (freshwater) ecosystems. Academic (i.e. university) researchers, applied researchers (e.g., lake managers), and members of the general public (i.e. recreational users) should be keenly interested in the results from this project. Educational training opportunities will include Native American high school interns as research assistants. Results will be published in peer-reviewed journals, while presentations to both scholarly and general-public audiences are planned.