Metagenome from the Muhlbacher Schwefelquelle aquifer

Organisms of the putatively deep-branching phylum Altiarchaeota are globally abundant carbon fixers in Earth's crust. In some subsurface biotopes across the globe, these mesophilic archaea dominate the community with up to 95% of the total cell counts, particularly in ecosystems high in carbon dioxide content. Based on the 'kill-the-winner' theory, we hypothesize that these archaea are frequent targets of previously unrecognized archaeal viruses. Indeed, preliminary analyses of CRISPR arrays and the predicted viromes of five different sampling sites on three different continents revealed 12 genomes of novel archaeal viruses that infect Altiarchaeota. However, it remains a mystery how stable and variable the viral community in these biotopes is. Consequently, we request metagenomic sequencing of three samples from a biotope enriched in Altiarchaeota to reconstruct a) the genome dynamics of novel viral genomes and their mutation rates and b) the infection history of the host over a period of four years. At the same time, this sequencing data will be the basis for designing of FISH probes for the novel archaeal viruses to investigate the infection of the hosts in situ. Consequently, the sequencing effort requested herein, will shed light onto dynamics of archaeal viruses and carbon flow in subsurface ecosystems and how these entities impact one of the most abundant carbon fixers in Earth's crust. Project PIs, Alexander Probst and Janina Rahlff.