Physiological state of microbial communities and mats of the bottom sediments in the marine shallow-water hydrothermal ecosystem of Kraternaya Bight (Kurile Islands)

Abstract

The physiological state of littoral and sublittoral microbial communities in a marine shallow-water hydrothermal ecosystem (Kraternaya Bight) was studied using lipid biomarkers. The ratio trans/cis (n-7) isomers of monoenic fatty acids (FAs) of polar lipids in intertidal and subtidal algobacterial and bacterial mats of the bight exceeded 0.1 significantly; this indicated a stress state in bacteria. No concomitant increase was found in the ratio of cyclopropane fatty acids to 16: 1 and 18: 1 (n-7) cis monoenic fatty acids. In bottom sediments, the ratio trans/cis (n-7) isomers of monoenic fatty acids was below 0.1. A positive correlation (r = 0.71) was revealed between the ratio trans/cis isomers of (n-7) monoenic fatty acids and the content of saturated fatty acids.