Microbiome of Supraglacial Systems on the Aldegonda and Bertel Glaciers (Western Spitsbergen Island)

Abstract

Microbial biomass, diversity of cultivated bacteria and micromycetes, as well as the number of functional nitrogen cycle genes in the supraglacial systems of the Aldegonde and Bertel glaciers were studied. Biomass of microorganisms varied from 2.54 to 722 µg/g of substrate. It has been shown for the first time that the majority (78.7–99.8%) of the microbial biomass of supraglacial objects is represented by fungi rather than prokaryotes. Main part (from 70 to 90%) of the fungal biomass was mycelium, the length of which varied from 6.70 to 537.51 m/g of substrate. The number of prokaryotes varied from 2.4 × 108 to 1.95 × 109 cells/g of substrate. The length of actinomycete mycelium varied from 2.6 to 62.61 m/g of substrate. The abundance of cultivated bacteria and actinomycetes varied from 3.3 × 104 to 1.2 × 106 CFU/g of substrate, and that of micromycetes varied from 2.2 × 101 to 1.7 × 104 CFU/g of substrate. Bacteria of the genera Arthrobacter, Bacillus, Rhodococcus, and Streptomyces, as well as micromycetes of the genera Antarctomyces, Cadophora, Hyphozyma, Teberdinia and Thelebolus dominated. Micromycetes Antarctomyces psychrotrophicus, Hyphozyma variabilis and Teberdinia hygrophila were found in Svalbard for the first time. The number of amoA genes in ammonium-oxidizing bacteria varied from 5.33×106 to 4.86 × 109; nitrogen fixation genes nifH, from 9.89 × 107 to 9.81 × 1010; nirK denitrification genes, from 4.82 × 107 to 3.34 × 1010 gene copies/g of substrate. The results obtained indirectly indicate the leading role of fungi in the microbiome of the supraglacial objects of Svalbard and the significant contribution of prokaryotes to the emission of greenhouse gases from them.