Collaborative Research: Stochasticity and Cryoconite Community Assembly and Function

冻石洞是完全被贫瘠的冰川冰包裹的生命的口袋。当吹到冰上的尘埃融化一个基本上孤立的小洞时，这些生命口袋就形成了，这个洞可以作为自己的微型生态系统发挥作用。这些尘埃中可能含有细菌、藻类或微小动物等微生物。洞内的微生物相互作用，执行更大生态系统的典型功能，如森林。低温石洞在极端寒冷的环境中尤其重要，比如南极干燥的山谷，在那里它们充当着生命的宝库。由于低温球藻的洞穴大多是封闭的，并持续多年，因此可以随着时间的推移进行追踪，以测试关于相互作用的有机体群落如何发展成为功能齐全的生态系统的基本科学问题。这个项目将对现有的和实验中创建的低温球体洞进行采样，以了解这些生态系统是如何发展的，以及随机过程(如哪些生物体首先到达那里)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并影响诸如低温球藻洞穴等微生态系统的功能的理解，而且还将提高我们对群落组装过程如何影响更大的生态系统(如森林)的功能的理解。更好地了解群落的建立、发展和对非生物因素的响应对于预测生态对环境变化的反应是至关重要的。揭示群落聚集、生物多样性和众多生态系统中的养分循环之间的联系是至关重要的，因为这些是决定生态对环境变化的反应的关键因素。冰锥石洞独特的、基本上孤立的性质提供了一个实验系统，将促进对推动群落聚集的过程(例如，分散限制、组装顺序和生态漂移等随机动力学)的基本理解。该项目将使用实地采样活动和一些操纵性实验来检验一个将群落和生态系统生态学的理论统一起来的假设：随机过程在多大程度上指导微生物群落聚集并影响生物多样性和生态系统过程中的区域格局。将对冻石洞进行采样，以比较水文连通洞和孤立洞之间的群落组成、环境因素和生态系统功能。还将在两个生长季节期间建造和监测新的冰锥石洞，以具体改变组装顺序和群落规模，从而将一项独特的操控实验与实地调查相结合，以解决与南极和其他地区相关的问题。将使用扩增子测序、元基因组学、显微镜、敏感的环境化学方法以及光合作用和呼吸测量来检验一系列与区域生物多样性模式、环境因素的异质性和生态系统过程的随机性有关的子假说。

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.