Endolithic communities in the McMurdo Dry Valleys: biomass, turnover, cyanobacteria and location – a preliminary insight

Abstract

In the McMurdo Dry Valleys, located in Southern Victoria Land, Antarctica, endolithic communities are important photoautotrophic primary producers. Being poikilohydric organisms their active time and carbon fixation rates rely on local water availability. In Antarctica the parallel variation in the severity of the thermal and hydric environment makes simple transect and gradient based modelling complicated. Here we interpret samples collected over several seasons in terms of rock type (sandstone, marble and granite) and location (distance from sea, altitude) on the colonization, species composition, chlorophyll content, biomass as well as stable carbon isotopic composition and 14 C age of the endolithic communities. Distance from coast was highly correlated with altitude of the sampling locations and this complicated disentangling of climatic drivers. Nevertheless, stable carbon isotopic composition allowed insight into hydration regime and 14C radiocarbon age into productivity. Endolithic communities in sandstone at high altitude sites have higher biomass but are less often active than communities in lowland granite.