@article {4962, title = {The underground network: Facilitation in soil bacteria}, journal = {Oikos}, year = {2024}, month = {06/2024}, abstract = {

Our understanding of the fundamental role that soil bacteria play in the structure and functioning of Earth\&$\#$39;s ecosystems is ever expanding, but insight into the nature of interactions within these bacterial communities remains rudimentary. Bacterial facilitation may enhance the establishment, growth, and succession of eukaryotic biota, elevating the complexity and diversity of the entire soil community and thereby modulating multiple ecosystem functions. Global climate change often alters soil bacterial community composition, which, in turn, impacts other dependent biota. However, the impact of climate change on facilitation within bacterial communities remains poorly understood even though it may have important cascading consequences for entire ecosystems. The wealth of metagenomic data currently being generated gives community ecologists the ability to investigate bacterial facilitation in the natural world and how it affects ecological systems responses to climate change. Here, we review current evidence demonstrating the importance of facilitation in promoting emergent properties such as community diversity, ecosystem functioning, and resilience to climate change in soil bacterial communities. We show that a synthesis is currently missing between the abundant data, newly developed models and a coherent ecological framework that addresses these emergent properties. We highlight that including phylogenetic information, the physicochemical environment, and species-specific ecologies can improve our ability to infer interactions in natural soil communities. Following these recommendations, studies on bacterial facilitation will be an important piece of the puzzle to understand the consequences of global change on ecological communities and a model to advance our understanding of facilitation in complex communities more generally.

}, keywords = {LTER-MCM, bacteria, climate change, facilitation, resilience, stress-gradient hypothesis}, issn = {0030-1299}, doi = {10.1111/oik.10299}, url = {https://nsojournals.onlinelibrary.wiley.com/doi/10.1111/oik.10299}, author = {Jorna, Jesse and Adams, Byron J. and Aanderud, Zachary T. and Frandsen, Paul B. and Cristina D. Takacs-Vesbach and K{\'e}fi, Sonia} } @article {4196, title = {Unimodal productivity{\textendash}diversity relationships among bacterial communities in a simple polar soil ecosystem}, journal = {Environmental Microbiology}, volume = {21}, year = {2019}, month = {07/2019}, abstract = {

Unlike other macroecological principles, relationships between productivity and diversity have not been effectively tested for microbial communities. Here we describe an experiment in which the availability of resources to soil bacterial communities was manipulated in a model system, the McMurdo Dry Valleys of Antarctica. Mannitol additions were used to simulate a productivity gradient such that a response in bacterial biomass production, taxonomic diversity and functioning (e.g., enzyme activity) were induced. Resource amendment induced a positive linear response in microbial productivity (P \< 0.001) but a unimodal (hump-shaped) response in microbial diversity at multiple taxonomic scales (P = 0.035). Putative oligotrophic (e.g., phyla Nitrospirae and Cyanobacteria) and copiotrophic (e.g., phylum Proteobacteria) taxa were apparent through substantial community turnover along the resource gradient. Soil enzyme activity was inversely related to bacterial biomass but positively related to diversity, suggesting the latter may be a stronger control over enzyme-mediated decomposition. The mechanisms behind this pattern are consistent with macroecological theory of a shift from environmental (e.g., stress tolerance) to biotic (e.g., competition) drivers with increasing resource availability. This evidence is among the first of its kind to document a significant unimodal productivity\–diversity relationship for soil bacteria.

}, keywords = {LTER-MCM}, doi = {10.1111/1462-2920.14639}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/1462-2920.14639}, author = {Kevin M. Geyer and John E. Barrett} } @article {3921, title = {Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake}, journal = {Applied and Environmental Microbiology}, volume = {82}, year = {2016}, month = {06/2016}, pages = {3659 - 3670}, abstract = {

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activated cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (Flavobacteria\ and\ Methylobacteriaceae) were independently associated with two key MCM lake microalgae (Isochrysis\ and\ Chlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite ofChlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake.

IMPORTANCE\ Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment.

}, keywords = {LTER-MCM}, issn = {0099-2240}, doi = {10.1128/AEM.00478-16}, url = {http://aem.asm.org/lookup/doi/10.1128/AEM.00478-16}, author = {Li, Wei and Podar, Mircea and Rachael M. Morgan-Kiss}, editor = {Kelly, R. M.} } @article {4169, title = {Unraveling ecosystem responses to climate change on the Antarctic continent through Long-Term Ecological Research}, journal = {BioScience}, volume = {66}, year = {2016}, month = {10/2016}, pages = {799 - 800}, keywords = {LTER-MCM}, issn = {0006-3568}, doi = {10.1093/biosci/biw131}, url = {https://academic.oup.com/bioscience/article/66/10/799/2236166}, author = {John C. Priscu} } @article {1099, title = {Understanding Terrestrial Ecosystem Response to Antarctic Climate Change}, journal = {Eos, Transactions American Geophysical Union}, volume = {94}, year = {2013}, month = {01/2013}, pages = {33 - 33}, keywords = {LTER-MCM}, doi = {10.1002/2013EO030009}, url = {http://onlinelibrary.wiley.com/doi/10.1002/2013EO030009/abstract}, author = {Joseph S. Levy and W. Berry Lyons and Byron Adams} } @article {1252, title = {Unique similarity of faunal communities across aquatic terrestrial interfaces in a polar desert ecosystem}, journal = {Ecosystems}, year = {2007}, keywords = {LTER-MCM}, doi = {LTER}, author = {Edward Ayres and Diana H. Wall and Byron Adams and John E. Barrett and Ross A. Virginia} } @inbook {1346, title = {Understanding the functions of biodiversity in soils and sediments will enhance global ecosystem sustainability and societal well-being}, booktitle = {Sustaining Biodiversity and Ecosystem Services in Soils Sediments}, year = {2004}, pages = {249-254}, publisher = {Island Press}, organization = {Island Press}, keywords = {LTER-MCM}, author = {Diana H. Wall and Richard D. Bardgett and Covich, A and P.V.R. Snelgrove}, editor = {Diana H. Wall} } @article {1423, title = {The use of anhydrobiosis by soil nematodes in the Antarctic Dry Valleys}, journal = {Functional Ecology}, volume = {14}, year = {2000}, month = {08/2000}, pages = {460-467}, type = {Journal}, keywords = {LTER-MCM, Biggie, survival strategies}, doi = {10.1046/j.1365-2435.2000.00442.x}, url = {http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2435.2000.00442.x/full}, author = {Amy M Treonis and Diana H. Wall and Ross A. Virginia} } @article {1445, title = {UV radiation and potential biological effects beneath the perennial ice cover of an antarctic lake}, journal = {Hydrobiologia}, volume = {427}, year = {2000}, pages = {155-165}, keywords = {LTER-MCM}, author = {Kepner, R.L. and Robert A. Wharton Jr. and Collier, R and Cockell, C and Jeffrey, W} }