Cultured bacterial diversity and the impact of human activity in cryoconites samples from Alps

Abstract

The relationship between human impact and the diversity of culturable bacteria in cryoconite samples from Alps was investigated by comparing physiological characteristics and phylogenetic analysis of 260 isolates. The ratio of isolates which grew only below 20&#61616

C was higher in samples with no or weak human impact compared to that in samples with strong human impact. In contrast, the ratio of isolates which grew as high as 37&#61616

C were higher in strongly affected samples. In most cases, protease activity at 10&#61616

C and 20&#61616

C seemed similar, but the ratio of isolates with higher protease activity at 10C than 20&#61616

C was higher when human impact were strong. In contrast, correlation of lipase activity with human impact was not evident. Isolates were included in the Actinobacteria, Bacteroidetes, Firmicutes, α-proteobacteria, ß-proteobacteria, and γ-proteobacteria and diversity was affected by human impact. Isolates included in the Arthrobacter, Bacillus, and Pseudorhodobacter were detected only from samples with no human impact while isolates included in the Enterobacteraceae, Oxalobacteraceae, Pedobacter, Rhodococcus, and Sphingomonas were detected from samples with human impact. These results suggested that human impact may influence on the composition of microbial communities and physiological characteristics of bacteria in cryoconites.