Benthic mat biomass, productivity (photosynthesis and respiration) and contributions to lake nutrient cycling in Lake Hoare, Taylor Valley

Comparative physiological measurements of the mat from different depths were taken in the very dark Lake Hoare for comparison with Lake Vanda. Three sites were sampled for microbial mat collections from a range of depths for analysis of pigments, biomass, composition and nutrients (C and N) and ash free dry weight. A series of experiments were conducted to determine the contributions of microbial mats to lake nutrient cycling and the rate of photosynthesis and nutrient uptake was assessed.

Sediment traps, left in situ for several seasons, were recovered and the contents were analysed for organic and inorganic carbon and nitrogen (including isotopic signatures) and pigments. Sediment cores were also taken for paleoecological analysis and long sediment cores from a range of depths including the bottom of the lake (at 24m) were obtained. Groundwater seepage zones were located and long term deployments of instruments in these seeps, designed to determine their role in solute dynamics, were made.