Group for Aquatic Microbial Ecology (GAME
GAME August 2018 (left to right: Alexander Probst, Janina Rahlff, Katrin Schwank, Dawid Krzeciesa, Alexandre Vaz Ramos, Till Bornemann, Ricardo Kruger)
Carbon cycling in the terrestrial subsurface
Ecophysiology of Altiarchaeota
1. Carbon cycling in the terrestrial subsurface
The subsurface houses more than 100 million petagrams (gigatons) of carbon, and thus represents the greatest resource of carbon on this planet. However, no climate change model considers this carbon reservoir, as it is believed not be bioavailable. Our investigations of subsurface microbial communities, particularly those in high-CO2 and anaerobic environments, showed a high capacity for carbon fixation. In fact, this process sustains complex microbial communities, which span most of the known tree of life. We are interested in how the carbon flux within such a community functions and investigate primary production, carbon recycling and other carbon-related processes in subsurface ecosystems. Our model system for exploring subsurface communities is the world’s largest CO2-driven geyser, the Geysir Andernach in Germany.
2. Ecophysiology of Altiarchaeota
Altiarchaeota are a newly recognized phylum, that is supposedly basal to all archaea on the tree of life. These uncultivated archaea are play an important role in Earth’s carbon cycle. In fact, they are one of the most abundant carbon fixers in Earth’s crust. Investigation of sulfidic springs in Germany, USA, and Japan have revealed that Altiarchaeota can dominate entire ecosystems and comprise about 95% of all cells in the ecosystem. We currently investigate the interaction of Altiarchaeota with other biological entities to fully understand the ecological role of these archaea in the subsurface.