Cryoconite Holes
Microbial Community Assembly in Cryoconite Holes, Dry Valleys, Antarctica
Cryoconite holes are pockets of microbial life encased in otherwise barren glacial ice. These pockets of life are made up of interacting microorganisms that carry out all the functions of a larger ecosystem, and as such provide unique opportunities to study how communities of organisms form and function - especially in extreme environments. Because cryoconite holes are mostly isolated from each other and from their surroundings, their community assembly is likely driven by stochastic processes. These include limited dispersal, variable assembly order, and ecological drift. We are using field sampling campaigns and a number of manipulative experiments to test novel hypotheses that unites theory in community and ecosystem ecology. We are also constructing new cryoconite holes to experimentally alter microbial assembly order and community size, thereby pairing a unique manipulative experiment with field surveys to address questions with relevance within and beyond the Antarctic. We use biogeochemical and DNA sequencing approaches to test a series of sub-hypotheses that relate stochasticity to patterns in regional biodiversity, heterogeneity in environmental factors, and ecosystem processes. This project started in in austral summer of 2016/2017 and is funded by grant from the NSF (OPP-2137375, Role of nutrient limitation and viral interactions on Antarctic microbial community assembly: A cryoconite microcosm study, and PLR-1443578, Collaborative Research: Stochasticity and Cyroconite Community Assembly and Function). The original proposal was written with Diana Nemergut before her untimely death in December, 2015. More information about this new project can be found here: cryoholes.wordpress.com Relevant Recent Publications: Schmidt SK et al. 2022. Microbial biogeochemistry and phosphorus limitation in cryoconite holes across the Taylor Valley, McMurdo Dry Valleys, Antarctica. Biogeochem 158: 313-323. [Reprint] McQueen JP et al. 2023. External and internal microbiomes of Antarctic nematodes are distinct, but more similar to each other than the surrounding environment. J. Nematology 55: [Reprint] McQueen, JP et al. 2022. Host identity is the dominant factor in the assembly of nematode and tardigrade gut microbiomes in Antarctic Dry Valley streams. Sci Reports 12: 20118. [Reprint] Rozwalak P et al. 2022. Cryoconite – From minerals and organic matter to bioengineered sediments on glacier surfaces. Science of the Total Environment 807: 150874 [Reprint] Sommers P, DL Porazinska, JL Darcy et al. 2020. Microbial species–area relationships in Antarctic cryoconite holes depend on productivity. Microorganisms 8: 1747. Zawierucha K et al. 2020. A hole in the nematosphere: tardigrades and rotifers dominate the cryoconite hole environment, whereas nematodes are missing. J. Zoology 313: 18-36. [Reprint] Sommers, P et al. 2019. Single Stranded DNA viruses in Antarctic cryoconite holes. Viruses 11: Vimercati, L., Darcy, J. L., Schmidt, S. K. 2019. The disappearing periglacial ecosystem atop Mt. Kilimanjaro supports both cosmopolitan and endemic microbial communities. Scientific Reports 9: 1-14. Sommers P., D.L. Porazinska, et al. 2019. Experimental cryoconite holes as mesocosms for studying community ecology. Polar Biology 42: 1973-1984. Sommers P. et al. 2019. Microbial communities in the sediments and water columns of frozen cryoconite holes in the McMurdo Dry Valleys, Antarctica. Frontiers Microbiology doi: 10.3389/fmicb.2019.00065 Sommers, P. et al. 2018. Diversity patterns of microbial eukaryotes mirror those of bacteria in Antarctic cryoconite holes. FEMS Microbiol. Ecol. 94: https://doi.org/10.1093/femsec/fix167 [Reprint] Darcy, J.L. et al.. 2017. Spatial autocorrelation of microbial communities atop a debris-covered glacier is evidence of a supraglacial chronosequence. FEMS Microbiol. Ecol. 93: 10.1093/femsec/fix095 [Reprint] |