EAPSI: Searching for links between protozoan communities and changes in nutrient availability over time in Antarctic Dry Valley soils

许多原生动物已被证明在调节细菌新陈代谢方面发挥着重要作用，而细菌新陈代谢对于地球上几乎所有生态系统的营养循环至关重要。所有生物体都依赖于这些循环过程，因此原生动物是地球上生命持续存在的组成部分。了解哪些原生动物物种在养分循环中发挥何种作用将导致更准确的环境模型、更强的操纵生物反应器中微生物群落的能力、更好地理解生态系统工程以及旨在提高农业生产力的援助项目。由于微生物群落的生态通常非常复杂，该项目将利用南极洲麦克默多干谷（MDV）生态系统相对简单的土壤来探索原生动物群落与养分循环之间的关系。新西兰汉密尔顿怀卡托大学的克雷格·卡里 (Craig Cary) 博士在描述南极环境中的微生物群落特征方面颇有造诣，并且能够接触到对于该项目至关重要的独特微观世界。 南极土壤将在人造土壤微观世界中培养较长时间，以捕捉自然界群落的动态。原生动物和细菌群落结构的变化将按照规定的时间间隔进行二次采样和测序。将分析土壤地球化学和养分浓度，将养分可用性与群落组成联系起来。为了为孵化实验提供背景，来自不同地点的环境 DNA 和一系列土壤化学成分也将被进行目标测序。将使用多维标度（MDS）推断细菌和原生动物物种相关性的重要性。这些数据将阐明MDV原生动物的栖息地适宜性模型，阐明群落的哪些元素分别是由非生物或生物限制驱动的。该 NSF EAPSI 奖项是与新西兰皇家学会合作资助的。

Many protozoa have been shown to play a major role in regulating metabolism in bacteria, which is central to nutrient cycling in virtually all ecosystems on Earth. All organisms depend on these cycling processes, and thus protozoa are integral to the continual existence of life on earth. Understanding which species of protozoa play which role in nutrient cycling will result in more accurate environmental models, a greater ability to manipulate microbial communities in bioreactors, an improved understanding of ecosystem engineering, and aid projects aimed at increasing agricultural productivity. Because the ecology of microbial communities is usually highly complex, this project will use soils from the relatively simple ecosystems of the McMurdo Dry Valleys (MDV) in Antarctica to explore the relationship between protozoan communities and nutrient cycling. Dr. Craig Cary at the University of Waikato in Hamilton, New Zealand is accomplished at characterizing microbial communities in Antarctic environments and has access to unique microcosms that will be essential for this project. Antarctic soil will be incubated in artificial soil microcosms for an extended period of time to capture the dynamics of a community in nature. Changes in protozoan and bacterial community structure will be subsampled and sequenced at prescribed intervals. Soil geochemistry and nutrient concentration will be analyzed to link nutrient availability to community composition. To provide context for the incubation experiment, environmental DNA from diverse locations and a range of soil chemistries will also be target-sequenced. Significance of bacterial and protozoan species correlation will be inferred using multidimensional scaling (MDS). These data will elucidate habitat suitability models for MDV protozoa, clarifying which elements of the community are driven by abiotic or biotic constraints, respectively. This NSF EAPSI award is funded in collaboration with Royal Society of New Zealand.