Karen's current project is investigating the impact of bacteria-phytoplankton interactions on the structure and functions of marine microbial communities. She is studying co-occurence of bacterial taxa and phytoplankton species to identify species interactions, and plans to study the bacterial metabolism involved in species specific interactions with phytoplankton species. During her first postdoc, she studied the impact of increase water colour and organic matter concentrations on the structure and functions of freshwater plankton communities (bacteria, phytoplankton and zooplankton). She was also interested in the biogeography of Gonyostomum semen, and the importance of light conditions and quality of organic matter on this phytoplankton species. During her PhD, she studied the life history and dispersal pattern of the invasive phytoplankton Gonyostomum semen using population genetic and phylogeographic tools. In addition, she investigated the grazing pressure on this species, showing that only limited grazing pressure apply on Gonyostomum, potentially helping this species to form dense populations.