Diversity of retrievable heterotrophic bacteria in Kongsfjorden, an Arctic fjord

Abstract

The diversity and abundance of retrievable pelagic heterotrophic bacteria in Kongsfjorden, an Arctic fjord, was studied during the summer of 2011 (June, August, and September). Retrievable bacterial load ranged from 103 to 107 CFU L−1 in June, while it was 104–106 CFU L−1 in August and September. Based on 16S rRNA gene sequence similarities, a higher number of phylotypes was observed during August (22 phylotypes) compared to that during June (6 phylotypes) and September (12 phylotypes). The groups were classified into four phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Bacteroidetes was represented only by a single member Leewenhoekiella aequorea during the three months and was dominant (40%) in June. However, this dominance changed in August to a well-known phytopathogenic species Rhodococcus fascians (32%), which could be a result of decrease in the phytoplankton biomass following the secondary bloom. It is the first report of Halomonas titanicae isolation from the Arctic waters. It showed an increase in its abundance with the intrusion of Atlantic water into Kongsfjorden. Increased abundance of Psychrobacter species in the late summer months coincided with the presence of cooler waters. Thus, the composition and function of heterotrophic bacterial community was fundamentally different in different months. This could be linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer.

Seasonal habitat drives intestinal microbiome composition in anadromous Arctic char (Salvelinus alpinus)

“…The Pseudomonas spp. are common, with at least 202 identified species, including pathogens to both plants and animals (Özen and Ussery, 2012), and with some species being psychrophilic (Reddy et al ., 2004; Sinha et al ., 2017). Bacteria affiliated with the genus Sphingomonas contributed to community similarity at the WFO site, and to a lesser extent at the ABR sites, making the habitat specificity of this genus unclear, but they are known to contribute to gut mucosa and modulate the immune response in mammals (Caballero and Pamer, 2015).…”

Lipid membrane modulation and pigmentation: A cryoprotection mechanism in Arctic pigmented bacteria

“…In the present work, five bacterial strains (Table ) were selected from the culture collection available at the National Centre for Antarctic and Ocean Research (Goa, India) based on the presence of pigments. These strains were isolated from Kongsfjorden, a glacial fjord on the west coast of Svalbard, following the standard procedures . The identification of strains was done by phylogenetic analysis of the well conserved 16S rRNA sequences.…”

Diversity of bacteria from Antarctica, Arctic, Himalayan glaciers and Stratosphere

“…Among the Bacillus species, Bacillus aryabhattai which has been reported only from the upper stratosphere, was isolated and is the first record from the Earth's surface. It was also observed that the diversity of retrievable heterotrophic bacteria in Kongsfjorden, an Arctic fjord was represented by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes and observed that the composition of heterotrophic bacterial community was linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer (Sinha et al, 2017).…”

“…Sea-ice contained bacterial lineages that belonged to Proteobacteria, Bacteroidetes, Planctomycetes and Chloroflexi (Junge et al, 2002;Brinkmeyer et al, 2003;Bottos et al, 2008) and sea water harboured significant proportions of Proteobacteria (>50%) and Bacteriodetes (25%) and Actinobacteria and Verrucomicrobia were present below 25% (Kirchman et al, 2010). Interestingly, a seasonal variation in bacterial abundance and change in phylotypes (belonging to the phyla Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes) was observed in Kongsfjorden, an Arctic fjord (Sinha et al, 2017).…”