Collaborative Research: Stochasticity and Cryoconite Community Assembly and Function

冰柱洞是生命的口袋，完全包裹在贫瘠的冰川冰中。 当灰尘吹到冰上融化时，这些生命的口袋就形成了一个小的，基本上孤立的洞，可以作为自己的小生态系统。 这些灰尘可能含有微生物，如细菌，藻类或微观动物。洞内的微生物相互作用，并执行较大生态系统（如森林）的典型功能。冰柱洞在极端寒冷的环境中特别重要，如南极干旱山谷，在那里它们作为生命的储存库。 由于冰尘洞大多是封闭的，并持续多年，它们可以随着时间的推移进行跟踪，以测试有关相互作用的生物群落如何发展成为功能齐全的生态系统的基本科学问题。 该项目将对现有的和实验创建的冰尘洞进行采样，以了解这些生态系统如何发展，以及随机过程（例如哪些生物首先到达那里）在多大程度上影响最终的群落组成和功能。 这些结果不仅将提高我们对微生物群落如何组装和影响微生态系统（如cryoconite holes）功能的理解，而且还将提高我们对群落组装过程如何影响较大生态系统（如森林）功能的理解。 更好地理解群落的建立、发展和对非生物因子的响应对于预测环境变化的生态响应是至关重要的，因为这些是决定生态响应的关键因素，因此必须解开群落聚集、生物多样性和众多生态系统中养分循环之间的联系。冰尘孔的独特的、很大程度上隔离的性质提供了一个实验系统，该系统将促进对过程的基本理解（例如，随机动力学，如扩散限制，组装顺序和生态漂移）驱动社区组装。 该项目将使用一个现场采样活动和一些操作实验来测试一个假设，统一的理论在社区和生态系统生态学：在何种程度上随机过程引导微生物群落组装和影响生物多样性和生态系统过程的区域模式。 将对冰柱洞进行取样，以比较水文连通和孤立洞之间的群落组成、环境因素和生态系统功能。 在两个生长季节的过程中，还将建造和监测新的冰尘洞，以专门改变组装顺序和群落规模，从而将独特的操纵实验与实地调查配对，以解决与南极及其他地区相关的问题。 扩增子测序，宏基因组学，显微镜，敏感的环境化学方法，光合作用和呼吸测量将被用来测试一系列的子假设，涉及随机性的模式，在区域生物多样性，环境因素的异质性，生态系统过程。

Cryoconite holes are pockets of life completely encased in otherwise barren glacial ice. These pockets of life form when dust blown onto the ice melts a small, largely isolated hole that can function as its own tiny ecosystem. This dust can contain microorganisms such as bacteria, algae, or microscopic animals. The microorganisms within the hole interact and carry out functions typical of a larger ecosystem, such as a forest. Cryoconite holes are especially important in extreme cold environments such as the Antarctic Dry Valleys, where they function as repositories of life. Because cryoconite holes are mostly enclosed and persist for years, they can be tracked over time to test fundamental scientific questions about how communities of interacting organisms develop to become fully functioning ecosystems. This project will sample existing and experimentally created cryoconite holes to understand how these ecosystems develop and to what degree random processes (such as which organisms get there first) affect the final community composition and functioning. The results will not only improve our understanding of how microbial communities assemble and affect the functioning of microecosystems such as cryoconite holes, but also how the processes of community assembly affect functioning of larger ecosystems, such as forests. A better understanding of community establishment, development, and response to abiotic factors are essential to forecasting ecological responses to environmental change.It is essential to unravel the links between community assembly, biodiversity, and nutrient cycling across numerous ecosystems because these are critical factors determining ecological responses to environmental change. The unique, largely isolated nature of cryoconite holes provides an experimental system that will advance fundamental understanding of the processes (e.g., stochastic dynamics such as dispersal limitation, assembly order, and ecological drift) driving community assembly. This project will use a field sampling campaign and a number of manipulative experiments to test a hypothesis that unites theory in community and ecosystem ecology: the degree to which stochastic processes guide microbial community assembly and affects regional patterns in biodiversity and ecosystem processes. Cryoconite holes will be sampled to compare community composition, environmental factors, and ecosystem functioning between hydrologically connected and isolated holes. New cryoconite holes will also be constructed and monitored over the course of two growing seasons to specifically alter assembly order and community size, thereby pairing a unique manipulative experiment with field surveys to address questions with relevance to the Antarctic and beyond. Amplicon sequencing, metagenomics, microscopy, sensitive environmental chemistry methods, and photosynthesis and respiration measurements will be used to test a series of sub-hypotheses that relate stochasticity to patterns in regional biodiversity, heterogeneity in environmental factors, and ecosystem processes.