Microbial metabolism in front of Kongsfjorden glaciers

To understand how the climate change affects the microbial community in the Arctic Sea and the ongoing heating results in cascading effects on the globally delicate climatic equilibrium is an important challenge of recent research performed in vulnerable ecosystems such as the Svalbard Islands. Within the UVASS (Unmanned Vehicles for Autonomous Sensing and Sampling) project, an unmanned marine vehicle (PROTEUS, Portable RObotic TEchnology for Unmanned Surveys), equipped with an automatic water multisampler, designed and built by ISSIA-CNR and IAMC-CNR respectively, were applied to study the response of planktonic communities, particularly prokaryotes, in the extreme environment of Kongsfjorden. During June 2017, seawater samples collected by those automatic systems along three transects located from glaciers to the open sea were analyzed for nutrients, organic matter and its utilization by microbial activity, using Biolog-Ecoplates(TM) and extracellular enzymatic activity rates (leucine aminopeptidase, beta-glucosidase and phosphatase activities). Richness and Shannon-Weaver index and Principal Component Analysis were used to depict differences in the microbial catabolic potential. Variations in organic matter distribution and in the functional diversity of microbial assemblages were observed. Freshwater runoff from ice melting was found to increase the amount of terrestrial organic matter to the fjord and microbial processes allowed organic matter decomposition.