Fungi are the primary degraders of plant matter and are globally important for the oxygen/carbon dioxide balance, among many other things. The origin of fungi is clearly aquatic, since we find most of the early diverging fungal lineages in freshwater and marine ecosystems, where they show specific adaptations such as motile spores. Thus, these aquatic fungal lineages can shed light on the origin of the terrestrial fungi and the unique enzymes that allow them to degrade plant polymers efficiently. Despite this knowledge, early diverging waterborne fungi are rarely investigated due to their microscopic size, their indistinguishable features, and the difficulty associated with keeping them in culture in the laboratory.
Our aim with this project was to shed light on the very poorly understood aquatic fungi (notably the phyla Chytridiomycota and Cryptomycota), many lineages of which are new or even unknown to science. We investigated these new fungi and detailed their taxonomy, functional processes, and ecological services in a range of freshwater systems. The overarching questions were: (1) What fungi are there in these systems? (2) What are their functions and roles? (3) What are the implications for the study of fungi, freshwater ecosystems, and ecology at large?
This EU project started in the beginning of July 2015 by an extensive sampling campaign of approximately 150 – mainly Swedish – lakes spanning the substantial national latitudinal gradient. We used state of the art DNA sequence analysis methods to establish what types of fungi were present in these freshwater systems. We found that several early diverging fungal lineages dominated the lake ecosystems, and it gradually became clear that approximately 25% of these fungal species were new, undescribed species that awaited formal description and scientific recognition. This opens up new perspectives for biodiversity research by showing that many important ecological processes are driven by organisms we know next to nothing about,
