Experimental cryoconite holes as mesocosms for studying community ecology
Cryoconite holes are surface melt-holes in ice containing sediments and typically organisms. In Antarctica, they form an attractive system of isolated mesocosms in which to study microbial community dynamics in aquatic ecosystems. Although microbial assemblages within the cryoconite holes most closely resemble those from local streams, they develop their own distinctive composition. Here, we characterize the microbial taxa over time in cryoconite holes experimentally created from supraglacial sediments to demonstrate their utility as experimental mesocosms. We used high-throughput sequencing to characterize the assemblages of bacteria and microbial eukaryotes before melt-in, then after one and two months. Within one month of melt-in, the experimental holes, now lidded with ice, were visually indistinguishable from natural cryoconite holes, and within two months their thermal characteristics matched those of natural holes. The microbial composition of the experimental cryoconite holes declined in richness and changed significantly in the relative abundance of various taxa, consistent with possible turnover. In particular, a dominant cyanobacterium, Nostoc sp., further increased its dominance over the other dominant cyanobacterial phylotype, and an initially rarer Flavobacterium sp. became one of the dominant taxa. The eukaryotes continued to be dominated by algae and tardigrades, with the relative abundance of the dominant alga, Macrochloris sp., increasing notably relative to the microfauna. These changes within a single growing season in newly formed lidded cryoconite holes created from exposed supraglacial sediments are consistent with primary production and microbial turnover, and provide a promising foundation for future work using such mesocosms.
KeywordsCryoconite Antarctic Bacteria Eukaryotes Algae Cyanobacteria
This work was conceptualized by the late Diana Nemergut, who is greatly missed. The authors would like to thank all the United States Antarctic Program staff who made these logistics feasible, UNAVCO for precision GPS support, and the BioFrontiers Sequencing Facility at the University of Colorado. Thanks also to Roberto Ambrosini, Jun Uetake, and an anonymous reviewer for comments that improved the manuscript. This work was funded by the United States National Science Foundation Polar Programs Awards 1443578 and 1443373.
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Conflict of interest
The authors declare that they have no conflict of interest.
- Amaral-Zettler LA, McCliment EA, Ducklow HW, Huse SM (2009) A method for studying protistan diversity using massively parallel sequencing of V9 hypervariable regions of small-subunit ribosomal RNA genes. PLoS ONE 4:e6372. https://doi.org/10.1371/journal.pone.0006372 CrossRefPubMedPubMedCentralGoogle Scholar
- Bagshaw EA, Tranter M, Fountain AG, Welch K, Basagic HJ, Lyons WB (2013) Do cryoconite holes have the potential to be significant sources of C, N, and P to downstreamdepauperate ecosystems of Taylor Valley, Antarctica? Arct Antarct Alp Res 45:440–454. https://doi.org/10.1657/1938-4246-45.4.440 CrossRefGoogle Scholar
- Caporaso JG, Kuczynski J, Stombaugh J, Bittinger K, Bushman FD, Costello EK, Fierer N, Peña AG, Goodrich JK, Gordon JI, Huttley GA, Kelley ST, Knights D, Koenig JE, Ley RE, Lozupone CA, McDonald D, Muegge BD, Pirrung M, Reeder J, Sevinsky JR, Turnbaugh PJ, Walters WA, Widmann J, Yatsunenko T, Zaneveld J, Knight R (2010) QIIME allows analysis of high-throughput community sequencing data. Nat Meth 7:335–336. https://doi.org/10.1038/nmeth.f.303 CrossRefGoogle Scholar
- Caporaso JG, Lauber CL, Walters WA, Berg-Lyons D, Huntley J, Fierer N, Owens SM, Betley J, Fraser L, Bauer M, Gormley N, Gilbert JA, Smith G, Knight R (2012) Ultra-high-throughput microbial community analysis on the Illumina HiSeq and MiSeq platforms. ISME J 6:1621–1624. https://doi.org/10.1038/ismej.2012.8 CrossRefPubMedPubMedCentralGoogle Scholar
- Franzetti A, Navarra F, Tagliaferri I, Gandolfi I, Bestetti G, Minora U, Azzoni RS, Diolaiuti G, Smiraglia C, Ambrosini R (2017) Temporal variability of bacterial communities in cryoconite on an Alpine glacier. Environ Microbiol Rep 9(71):78. https://doi.org/10.1111/1758-2229.12499 CrossRefGoogle Scholar
- Fukami T (2015) (2015) Historical contingency in community assembly: Integrating niches, species pools, and priority effects. Ann Rev Ecol Evol Syst 46:1–23. https://doi.org/10.1146/annurev-ecolsys-110411-160340 CrossRefGoogle Scholar
- Hervé M (2018) RVAideMemoire: testing and plotting procedures for biostatistics. R package version 0.9–69–3. https://CRAN.R-project.org/package=RVAideMemoire
- MacArthur RH, Wilson EO (1967) The theory of island biogeography. Princeton University Press, New JerseyGoogle Scholar
- Mueller DR, Vincent WF, Pollard WH, Fritsen CH (2001) Glacial cryoconite ecosystems: a bipolar comparison of algal communities and habitats. Nova Hedwig Beih 123:173–198Google Scholar
- Nordenskjöld NE (1875) Cryoconite found 1870, July 19th–25th, on the inland ice, east of Auleitsivik Fjord, Disco Bay, Greenland. Geolog Mag 2:157–162Google Scholar
- Oksanen J, Guillaume Blanchet F, Friendly M, Kindt R, Legendre P, McGlinn D, Minchin PR, O’Hara RB, Simpson GL, Solymos P, Stevens MHH, Szoecs E, Wagner H (2018) vegan: Community Ecology Package. R package version 2.5-1. https://CRAN.R-project.org/package=vegan
- Pinheiro J, Bates D, DebRoy S, Sarkar D, R Core Team (2018) nlme: Linear and Nonlinear Mixed Effects Models. R package version 3.1–137, https://CRAN.R-project.org/package=nlme.
- Porazinska DL, Fountain AG, Nylen TH, Tranter M, Virginia RA, Wall DH (2004) The biodiversity and biogeochemistry of cryoconite holes from McMurdo Dry Valley glaciers, Antarctica. Arct Antarct Alp Res 36:84–91. https://doi.org/10.1657/1523-0430(2004)036[0084:TBABOC]2.0.CO;2 CrossRefGoogle Scholar
- R Core Team (2018) R: A language and environment for statistical computing. v3.3.2 https://www.R-project.org/ Vienna, Austria. R Foundation for Statistical Computing.
- Sommers P, Darcy JL, Porazinska DL, Gendron EM, Fountain AG, Zamora F, Vincent K, Cawley KM, Solon AJ, Vimercati L, Ryder J, Schmidt SK (2019) Comparison of microbial communities in the sediments and water columns of frozen cryoconite holes in the McMurdo Dry Valleys. Antarctica. Front Microbiol 10:65CrossRefPubMedGoogle Scholar
- Tedesco M, Foreman CM, Anton J, Steiner N, Schwartzman T (2013) Comparative analysis of morphological, mineralogical and spectral properties of cryoconite in Jakobshavn Isbrae, Greenland, and Canada Glacier, Antarctica. Ann Glaciol 54:147–157. https://doi.org/10.3189/2013AoG63A417 CrossRefGoogle Scholar
- Telling J, Anesio AM, Tranter M, Fountain AG, Nylen T, Hawkings J, Singh VB, Kaur P, Musilova M, Wadham JL (2014) Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes. Front Microbiol 5:694. https://doi.org/10.3389/fmicb.2014.00694 CrossRefPubMedPubMedCentralGoogle Scholar
- Zamora F (2018) Measuring and modeling evolution of cryoconite holes in the McMurdo DryValleys, Antarctica. MS Thesis, Portland State University. https://doi.org/10.15760/etd.6590