Microbiome of Soils and Supraglacial Objects in Background and Oil-Polluted Ecosystems of Hayes Island, Franz Josef Land

Abstract

The microbiome of soils and supraglacial formations in background and oil-polluted ecosystems of Hayes Island (Franz Josef Land) was studied using the methods of luminescent microscopyreal-time and polymerase chain reaction. The biomass of microorganisms ranged from 81 to 666 μg C/g substrate; its larger part (up to 88%) was represented by fungi. The length of the fungal mycelium reached more than 360 m/g substrate. The number of prokaryotes varied from 4.0 × 10⁷ to 3.75 × 10⁹ cells/g substrate; the length of actinomycete hyphae reached 40 m/g substrate. Up to 78% of detected prokaryotic cells were represented by small nanoforms, which is typical for extreme ecosystems. The proportion of viable microbial cells gained maximum (74–86%) in surface organic horizons and minimum (29–54%) in mineral supra-permafrost layers. Bacteria dominated in the prokaryotic complex (from 5.14 × 10⁵ to 5.05 × 10¹⁰ 16S rRNA copies/g soil); the content of archaea was lower: from 8.46 × 10⁵ to 2.28 × 10⁹ 16S rRNA copies/g substrate. The amount of fungal ITS rRNA in the soil samples ranged from 6.47 × 10⁴ to 8.67 × 10¹⁰ copies. The number of copies of the alkB gene (synthesis of alkane monooxygenase for the destruction of n-alkanes of hydrocarbons) varied from 1.2 × 10¹ to 1.8 × 10⁵ copies/g substrate and sharply decreased from surface to deep horizons. Oil-contaminated soils and supraglacial objects contained a smaller biomass, but a larger number of ribosomal genes of microorganisms as compared with background ecosystems. An exponential decrease in the analyzed quantitative parameters of microorganisms from surface to deep soil horizons was observed.