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，而新陈代谢是地球上几乎所有生态系统中营养循环的核心。所有的有机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所不可或缺的。了解哪些种类的原生动物在养分循环中扮演哪些角色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，对生态系统工程的更好理解，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是高度复杂的，该项目将使用南极洲麦克默多干燥山谷(MDV)相对简单的生态系统中的土壤来探索原生动物群落和营养循环之间的关系。新西兰汉密尔顿怀卡托大学的克雷格·卡里博士擅长描述南极环境中的微生物群落，并能够获得对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孵化很长一段时间，以捕捉自然界中群落的动态。原生动物和细菌群落结构的变化将按规定的间隔进行二次抽样和测序。将对土壤地球化学和养分浓度进行分析，将养分有效性与群落组成联系起来。为了为孵化实验提供背景，还将对来自不同地点和一系列土壤化学的环境DNA进行目标测序。将使用多维尺度(MDS)来推断细菌和原生动物物种关联的重要性。这些数据将阐明MDV原生动物的栖息地适宜性模型，阐明群落的哪些要素分别由非生物或生物限制驱动。这项NSF EAPSI奖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.