Endolithic bacterial communities in rock coatings from Kärkevagge, Swedish Lapland

Abstract

Rock coatings in Kärkevagge, Swedish Lapland, are widespread and mineralogically diverse. A preliminary study of the rock coatings revealed higher than expected bacterial diversity for an endolithic environment in the arctic. Using 454 Roche pyrosequencing of the 16S rRNA gene, nine rock coating samples from three different coating mineralogies were sequenced. The three coating types include Fe films of goethite and hematite, sulfate crusts of jarosite and gypsum, and aluminum glazes of basaluminite and alunite. Over 20,000 quality sequences were analyzed, and over 2800 operational taxonomic units were identified. Diversity indices and richness estimates confirmed high levels of diversity, particularly in the sulfate crusts with diversity indices at the level of complex soils. Inferred physiology shows the presence of both heterotrophs and autotrophs, with genera of autotrophic Fe and S metabolisms present in at least 2% of the total for each coating type. The most common phyla included Proteobacteria, Acidobacteria, and Actinobacteria - all common soil taxa. Coatings also showed distinct community structure between coating mineralogies. Given the diversity in coating types found in areas receiving the same chemical and environmental inputs, the distinct microbial communities suggest a biological role in coating development.

Endolithic microbial composition in Helliwell Hills, a newly investigated Mars‐like area in Antarctica

“…Biodiversity estimates of these communities were consistent with previous investigations of endoliths but harbour a slightly lower diversity of both eukaryotic and prokaryotic assemblages previously studied (Marnocha and Dixon, 2014; Archer et al ., 2017; Selbmann et al ., 2017; Coleine et al ., 2018a, 2018b), dominated by a restricted number of highly specialized species. For instance, fungal species richness found in HH in this study ranged from 13 to 20 and bacterial from 39 to 55, while 17–111 and 50–300 fungal and bacterial OTUs respectively, were retrieved from samples collected in McMurdo Dry Valleys (SVL) and NVL (Coleine et al ., 2018a, 2019); these findings may be due to lower number of samples ( n = 3) collected from HH.…”

Editorial: Acidobacteria – Towards Unraveling the Secrets of a Widespread, Though Enigmatic, Phylum

“…Its members are prevalent in terrestrial environments, being the third most abundant soil phylum (Delgado-Baquerizo et al, 2018). Typically found in aquatic and terrestrial systems, they also occur in harsh environments such as acidic mine drainage (Kishimoto et al, 1991;Kleinsteuber et al, 2008;Falagán et al, 2017), rock faces (Zimmermann et al, 2006;Kelly et al, 2010;Marnocha and Dixon, 2014) or desert soil (Kuske et al, 1997;Dunbar et al, 2002). Despite their ubiquity and high 16S rRNA gene sequence abundance and diversity especially in soil habitats (Barns et al, 1999;Janssen, 2006;Fierer, 2017), knowledge on the ecology of Acidobacteriota is still surprisingly fragmentary, not least due to challenges in cultivating representative strains.…”

Natural Extracellular Electron Transfer Between Semiconducting Minerals and Electroactive Bacterial Communities Occurred on the Rock Varnish

“…Over the past decades, the microbial diversity of rock varnish in different geographical settings worldwide have gained considerable attention. A diverse microbial ecology of varnish has been analyzed by culture–independent molecular methods from different sites such as the Death Valley, Mojave Desert, Whipple Mountains and Black Canyon (Krumbein and Jens, 1981; Perry et al, 2002; Schelble et al, 2005; Kuhlman et al, 2006, 2008; Northup et al, 2010; Marnocha and Dixon, 2014; Esposito et al, 2015). Despite many published works on mineral composition and microbial diversity of rock varnish all over the world, only a few studies have focus on microbial diversity in Xinjiang, China.…”