Benthic Microbial Mats ice-covered Antarctic lakes
Complete microprofiles under extreme conditions
The Unisense MiniProfiler was deployed into two perennially ice-covered lakes of McMurdo Dry Valleys in Antarctica to study their laminated photosynthetic microbial communities. Temperature above the ice was approximately -15oC and below the ice around 0oC. The researchers drilled holes into the ice covers to lower the MiniProfiler into the lakes. The deployment of the MiniProfiler at the lake floors and away from the ice holes were guided by a tethered diver.
The laminations of the microbial communities represent annual growth accumulations. The ice on the lakes was several meters thick and its optical properties may influence the carbon fixation rates and thus the lamination thickness. The researchers studied this by doing simultaneous measurements of dissolved oxygen in the diffusive boundary layers above the mats, chlorophyll fluorescence, and downwelling irradiance of photosynthetically active radiation.