Microbial biogeography, speciation and adaptation

The composition and diversity of microbial communities varies over the Earth. We explore these biogeographical patterns in various freshwater ecosystems, the Baltic Sea, the Southern Ocean and other aquatic habitats. Many of our projects use a metacommunity approach to understand the dynamics behind spatial distribution patterns. We are for example investigating the importance of local and regional factors acting on the composition and richness of bacterial communities at the local scale. We also address how these factors change over time and space and in response to environmental perturbations and how they are related to changes in ecosystem functioning. Studies of long and short-term temporal dynamics provide such information and are for example carried out at the well-studied Lake Erken, but also in experimental laboratory systems and other marine and freshwater sites such as lakes and rock pools.
We are also turning our attention to the biogeography specific phylogenetic groups of bacteria and archaea such as the alphaproteobacterial clade SAR11 and the ubiquitous freshwater Actinobacteria ac1. In this work genomic combined with phylogenetic and population genetic approaches are used to investigate genetic and ecological patterns either at the level of individual cells, or populations. Several projects focus on the role of salinity as an ecological and evolutionary barrier for bacteria and archaea.