Microbial Diversity in a Permanently Cold and Alkaline Environment in Greenland

Abstract

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California.

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

“…Recent amplicon sequencing studies of the microbial diversity in the apex of ikaite columns showed the presence of a phototrophic surface‐associated community dominated by cyanobacteria (Glaring et al ., ; Trampe et al ., ). The very first characterization of the in situ ikaite microenvironment was recently reported by Trampe et al .…”

“…The Ikka fjord in SW Greenland harbours a unique assemblage of underwater tufa columns composed of the hexahydrated carbonate mineral ikaite (Pauly, 1963;Buchardt et al, 1997), which forms a porous matrix harbouring a diverse assemblage of microbes (Stougaard et al, 2002;Vester et al, 2013;Glaring et al, 2015). Hundreds of columns are situated in the innermost part of the Ikka fjord in South-western Greenland (Seaman and Buchardt, 2006), while ikaite column formation or larger solid ikaite assemblages have not been documented from other locations.…”

“…Recent amplicon sequencing studies of the microbial diversity in the apex of ikaite columns showed the presence of a phototrophic surface-associated community dominated by cyanobacteria (Glaring et al, 2015;Trampe et al, 2016). The very first characterization of the in situ ikaite microenvironment was recently reported by Trampe et al (2016), who demonstrated the presence of active photosynthesis by a mixed microalgal and cyanobacterial community inhabiting the ikaite column apex, which is a dynamic microhabitat characterized by steep O 2 , pH and light gradients.…”

Genomic and exoproteomic analyses of cold‐ and alkaline‐adapted bacteria reveal an abundance of secreted subtilisin‐like proteases

“…The columns are formed by precipitation of calcium carbonate from the mixture of seawater and alkaline spring water, and the interior of the columns is permanently cold (less than 6°C) and alkaline (above pH 10) (Buchardt et al, 1997;Hansen et al, 2011). It has previously been demonstrated that the columns are home to a diverse bacterial community adapted to these conditions (Schmidt et al, 2006;Vester et al, 2013) and a potential source of novel enzymes (Schmidt and Stougaard, 2010;Vester et al, 2014Vester et al, , 2015Glaring et al, 2015). Similar extreme conditions can be found in a series of alkaline ponds with pH values above 10 located in the McMurdo Dry Valley region, Antarctica (Jungblut et al, 2012).…”

Belliella buryatensis sp. nov., isolated from alkaline lake water

“…Based on metagenomic data, the abundance of Bacteroidetes is about 10-20 % in alkaline lake sediments (Xiong et al, 2012;Zaitseva et al, 2014;Glaring et al, 2015). Bacteroidetes has an important role in the marine carbon cycle, involved in the degradation of high-molecular-mass compounds such as cellulose, agar and chitin (Cottrell & Kirchman, 2000;Kirchman, 2002;Abell & Bowman, 2005).…”