The effect of geographic location and physiochemical characteristics on the cryoconite prokaryotic communities from the Arctic, Antarctic, and Central Caucasus regions

Abstract

Cryoconites are the deposits on the surface of glaciers that create specific ecological niches for the development of microorganism communities. The sediment material can vary in origin, structure, and nutrient content, creating local variations in the growth conditions. An additional factor of variability is the location of the glaciers, as they are found in different climatic zones in the high mountain regions and closer to the poles. Here we studied the common and specific features of the microbial communities from five glaciers representing different parts of the world, including the Arctic (Mushketova in Severnaya Zemlya, IGAN in Polar Ural), Antarctic (Pimpirev on Livingstone Island) and Caucasus (Skhelda und Garabashi in Central Caucasus), with the latter being presented for the first time. According to the chemical parameters of the cryoconites, each region had specific properties: Arctic cryoconites had higher nitrates values and microelements content, Antarctic - organic carbon, ammonium, and potassium, Caucasus - alkaline pH and high phosphorus content. Analysis of data from high-throughput sequencing of the 16S rRNA gene showed that although cryoconite microbiomes are composed of similar bacterial phyla (Pseudomonadota, Cyanobacteria, Bacteroidota, Acidobacteriota, and Actinobacteriota), at a low taxonomic level they are highly diverse: only several common phylotypes were identified for all glaciers. The WGSNA analysis revealed three groups of microorganisms, that significantly change their abundance corresponding with three geographical locations and chemical parameters of cryoconites. Our work demonstrates that cryoconite creates a specific ecological niche that facilitates the growth of predominantly autotrophic microorganisms, but local factors and physical isolation create specific patterns for each of such diversity hotspots.