The cold microbial majority - Ecophysiology, biogeography, and genomics of psychrophilic sulfate-reducing microorganisms in arctic marine sediments

Microbial physiology
Nutrient cycles

Molecular biology techniques have provided insights into the tremendous genetic diversity, abundance, and distribution of microorganisms on planet Earth. However, we still have a very limited understanding of the metabolic function and thus ecological role of most environmental microorganisms because only a minute fraction of this ‘microbial majority’ is cultivated. Prime examples are sulfate-reducing microorganisms, ubiquitous inhabitants of anoxic seafloor sediments and key catalysts of the marine sulfur and carbon cycles. Although more than 90% of the seafloor area is exposed to temperatures permanently below 4°C, most cultivated sulfate-reducing microorganisms are meso- or thermophiles and thus the physiological and genomic features of cold-adapted sulfate-reducing microorganisms are poorly characterized. This project aims to fill this gap by using a cultivation-independent approach that combines substrate-mediated isotope labeling, high-throughput community analysis (microarrays, amplicon sequencing) and high-resolution single cell techniques to yield novel insights into the biogeography, ecophysiology, and genetic makeup of a microbial guild that is of global importance in the oceans.

This project is funded by the Austrian Science Fund (FWF) P25111-B22.