CAREER:Protist Nutritional Strategies in Permanently Stratified Antarctic Lakes

这项职业提案将支持一名职业早期的女性PI在极地生物学和环境微生物学领域建立一个综合研究和教育计划，重点是高纬度冰盖南极湖泊系统中的单细胞真核生物(原生生物)。原生生物在能量流动和物质循环中发挥着重要作用，既是初级生产者(通过光合作用固定无机碳)，也是消费者(通过吞噬消化捕食细菌)。麦克默多干谷(MDV)位于南极洲维多利亚地，拥有微生物群落，这些微生物群落隔离在常年冰盖湖泊独特的水生生态系统中。这些湖泊只支持化学分层水柱中的微生物群落，不受季节性混合、外来输入或直接人类影响的影响。这个项目将利用永久分层的生物地球化学，这种化学在几个MDV湖泊的水柱中是独一无二的，以解决我们对水生食物网中原生生物营养功能的理解方面的空白。这项拟议的研究将考察(1)永久生物地球化学梯度对原生生物营养战略的影响，(2)主要非生物驱动因素(光和营养)对两个关键的混合营养和光自养原生生物物种分布的影响，以及(3)与低纬(富营养)流域相比，周期性营养脉冲对高纬度(超寡营养)MDV湖泊混合营养生物群落的影响。该项目将结合野外、实验室和现场培养研究的结果，对微生物生态学和环境微生物学领域产生影响，以合成水生食物网中原生生物营养作用的新模型。这一拟议项目的研究部分将与开发两项新的教育活动紧密结合，旨在利用与极地生物研究相关的内在兴奋。教育目标是：1)在微生物学专业的核心本科课程中建立极地生物学教学模块；2)开发教学模块，让中学女生参与STEM学科。本科生和中学女生还将与一名博士生一起在俄亥俄州当地的分水岭进行实验。

This CAREER proposal will support an early career female PI to establish an integrated research and education program in the fields of polar biology and environmental microbiology, focusing on single-celled eukaryotes (protists) in high latitude ice-covered Antarctic lakes systems. Protists play important roles in energy flow and material cycling, and act as both primary producers (fixing inorganic carbon by photosynthesis) and consumers (preying on bacteria by phagotrophic digestion). The McMurdo Dry Valleys (MDV) located in Victoria Land, Antarctica, harbor microbial communities which are isolated in the unique aquatic ecosystem of perennially ice-capped lakes. The lakes support exclusively microbial consortia in chemically stratified water columns that are not influenced by seasonal mixing, allochthonous inputs, or direct human impact. This project will exploit permanently stratified biogeochemistry that is unique across the water columns of several MDV lakes to address gaps in our understanding of protist trophic function in aquatic food webs. The proposed research will examine (1) the impact of permanent biogeochemical gradients on protist trophic strategy, (2) the effect of major abiotic drivers (light and nutrients) on the distribution of two key mixotrophic and photoautotrophic protist species, and (3) the effect of episodic nutrient pulses on mixotroph communities in high latitude (ultraoligotrophic) MDV lakes versus low latitude (eutrophic) watersheds. The project will impact the fields of microbial ecology and environmental microbiology by combining results from field, laboratory and in situ incubation studies to synthesize new models for the protist trophic roles in the aquatic food web. The research component of this proposed project will be tightly integrated with the development of two new education activities designed to exploit the inherent excitement associated with polar biological research. The educational objectives are: 1) to establish a teaching module in polar biology in a core undergraduate course for microbiology majors; 2) to develop an instructional module to engage middle school girls in STEM disciplines. Undergraduates and middle school girls will also work with a doctoral student on his experiments in local Ohio watersheds.