Bacterial carbon production in glacier-fed streams: a regional and spatiotemporal comparison

This study looks out bacterial carbon production (BCP) of 52 glacier fed streams from Greenland, New-Zealand, Russia and Switzerland. BCP is an important parameter to describe microbial communities in their environment. It reflects the capacity of the bacteria to grow but also to impact its environment through biofilm formation. The goal of this study is to assess the range of BCP between different environments with spatial and temporal diversities. In one hand, three glacial floodplains from Switzerland have been investigated on a fine spatial resolution with a differentiation in the stream water origin (groundwater, glacier-fed water and mixed) and the time of the snow-free season (early and late). On the other hand 49 sites from Greenland, New-Zealand and Russia have been sampled in two locations for each glacier fed-streams : one close to the glacier front and one other several hundred meters downstream. Main conclusions of this study are that glacier-fed stream are varying environment with different patterns of bacterial growth. Some of these streams have low BCP and some other high. Origin of the water may influence BCP but also the distance to the glacier front. However, glacierfed streams are very complex environments with lots of factors that interact between each other and therefore patterns are not universal.