Microbial Species–Area Relationships in Antarctic Cryoconite Holes Depend on Productivity

Sommers, Pacifica; Porazinska, Dorota L.; Darcy, John L.; Gendron, Eli M. S.; Vimercati, Lara; Solon, Adam J.; Schmidt, Steven K.

doi:10.3390/microorganisms8111747

Cited by 10 publications

(7 citation statements)

References 71 publications

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“…Likewise, Chlorococcum sp., the most abundant algal phylotype in crusts was also the most common alga in cryoconite holes of the valley (Sommers et al, 2019a). This link is also seen with heterotrophic bacterial genera common in our soils (e.g., Sphingomonas, Blastocatella) that were also found in high relative abundance in cryoconite holes across Taylor Valley (Sommers et al, 2020). Although an in-depth analysis of the comparisons between terrestrial mountain habitats and cryoconite hole sediments is beyond the scope of this paper, more investigation into whether high-elevation soils are the main source of inoculum for cryoconite holes is warranted.…”

Section: Broader Relevance Of This Studysupporting

confidence: 72%

Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica

et al. 2021

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Cold, dry, and nutrient-poor, the McMurdo Dry Valleys of Antarctica are among the most extreme terrestrial environments on Earth. Numerous studies have described microbial communities of low elevation soils and streams below glaciers, while less is known about microbial communities in higher elevation soils above glaciers. We characterized microbial life in four landscape features (habitats) of a mountain in Taylor Valley. These habitats varied significantly in soil moisture and include moist soils of a (1) lateral glacial moraine, (2) gully that terminates at the moraine, and very dry soils on (3) a southeastern slope and (4) dry sites near the gully. Using rRNA gene PCR amplicon sequencing of Bacteria and Archaea (16S SSU) and eukaryotes (18S SSU), we found that all habitat types harbored significantly different bacterial and eukaryotic communities and that these differences were most apparent when comparing habitats that had macroscopically visible soil crusts (gully and moraine) to habitats with no visible crusts (near gully and slope). These differences were driven by a relative predominance of Actinobacteria and a Colpodella sp. in non-crust habitats, and by phototrophic bacteria and eukaryotes (e.g., a moss) and predators (e.g., tardigrades) in habitats with biological soil crusts (gully and moraine). The gully and moraine also had significantly higher 16S and 18S ESV richness than the other two habitat types. We further found that many of the phototrophic bacteria and eukaryotes of the gully and moraine share high sequence identity with phototrophs from moist and wet areas elsewhere in the Dry Valleys and other cold desert ecosystems. These include a Moss (Bryum sp.), several algae (e.g., a Chlorococcum sp.) and cyanobacteria (e.g., Nostoc and Phormidium spp.). Overall, the results reported here broaden the diversity of habitat types that have been studied in the Dry Valleys of Antarctica and suggest future avenues of research to more definitively understand the biogeography and factors controlling microbial diversity in this unique ecosystem.

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Section: Broader Relevance Of This Studysupporting

confidence: 72%

Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica

et al. 2021

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“…A Qubit assay was used to quantify all DNA concentrations prior to DNA amplification. Extracted DNA concentrations were standardized to 1 g of dry soil to serve as a proxy for microbial biomass (Sommers et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

Context‐dependent role of abiotic and biotic factors structuring nematode communities along two environmental gradients

et al. 2022

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Although abiotic environmental factors have been historically regarded as the dominant deterministic process in microbial community assembly, recent studies indicate that biotic interactions may be equally significant. However, the extent to which both processes are important in assembly of belowground communities is unknown. Along two environmental gradients: alkalinity (ranging from pH ~7 to ~11) and habitat type (lakes, shorelines, and prairies around lakes) present in the Western Nebraska Sandhills, we used 18S rRNA gene marker metabarcoding and statistical analyses, including generalized dissimilarity modelling (GDM), to evaluate the dynamics between abiotic and biotic factors that might play a role in nematode community assembly. Lakes supported the least diverse and prairies the most diverse communities with completely distinct compositions. We also observed a potential role of alkalinity in shaping these communities but only in lakes. Generally, GDMs indicated the influence of both abiotic and biotic factors. However, their relative importance in explaining community variability was dependent on the habitat. Biotic factors influenced the lake communities most, followed by shorelines and prairies, explaining ~47%, 27% and 8% of the variation, respectively. In contrast, the role of abiotic factors was relatively similar in lakes, shorelines and prairies (~15%, 18% and 14% of the variation, respectively). Most variation in the shorelines (62%) and prairies (82%) remained unexplained, suggesting the potential importance of factors associated with specific traits or a stronger role of stochastic processes. Nevertheless, our findings suggest both deterministic processes are important in nematode community assembly, but their specific contributions are context‐dependent.

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“…There are additional community assembly theories such as the island species-area relationships (MacArthur and Wilson 1967) which describes the macroecological pattern of an increase in number of species with an increase in area of an island. Sommers et al 2020 showed that relationship Fig. 7 CCA of eukaryote community composition for absolute counts of OTUs.…”

Section: Of Terrestrial Ponds On Ross Island and Mcmurdo Drymentioning

confidence: 99%

“…The highest richness was found in Conophyton Pond, which was one of the smaller ponds, and Duet Pond with the largest area had the median richness, with Salt Pond being of medium size having the lowest richness. However, a larger number of samples and bigger range of habitat areas would be needed to be able to apply the mathematical model as done in the study by Sommers et al (2020).…”

Section: Of Terrestrial Ponds On Ross Island and Mcmurdo Drymentioning

confidence: 99%

16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

2021

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The undulating ice of the McMurdo Ice Shelf, Southern Victoria Land, supports one of the largest networks of ice-based, multiyear meltwater pond habitats in Antarctica, where microbial mats are abundant and contribute most of the biomass and biodiversity. We used 16S rRNA and 18S rRNA gene high-throughput sequencing to compare variance of the community structure in microbial mats within and between ponds with different salinities and pH. Proteobacteria and Cyanobacteria were the most abundant phyla, and composition at OTU level was highly specific for the meltwater ponds with strong community sorting along the salinity gradient. Our study provides the first detailed evaluation of eukaryote communities for the McMurdo Ice Shelf using the 18S rRNA gene. They were dominated by Ochrophyta, Chlorophyta and Ciliophora, consistent with previous microscopic analyses, but many OTUs belonging to less well-described heterotrophic protists from Antarctic ice shelves were also identified including Amoebozoa, Rhizaria and Labyrinthulea. Comparison of 16S and 18S rRNA gene communities showed that the Eukaryotes had lower richness and greater similarity between ponds in comparison with Bacteria and Archaea communities on the McMurdo Ice shelf. While there was a weak correlation between community dissimilarity and geographic distance, the congruity of microbial assemblages within ponds, especially for Bacteria and Archaea, implies strong habitat filtering in ice shelf meltwater pond ecosystems, especially due to salinity. These findings help to understand processes that are important in sustaining biodiversity and the impact of climate change on ice-based aquatic habitats in Antarctica.

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Microbial Species–Area Relationships in Antarctic Cryoconite Holes Depend on Productivity

Cited by 10 publications

References 71 publications

Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica

Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica

Context‐dependent role of abiotic and biotic factors structuring nematode communities along two environmental gradients

16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

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