Fungi in lake ecosystems

This review highlights the presence and ecological roles of fungi in lakes, and aims to stimulate research in aquatic mycology. In the study of lentic systems, this field is an almost completely neglected topic and, if considered at all, has often been restricted to specific groups of fungi, such as yeasts, filamentous fungi (e.g. aquatic hyphomycetes), or phycomycetes (an obsolete taxonomic category that included various fungal and fungal-like organisms). We document that aquatic fungi are common in various lentic habitats. They play potentially crucial roles in nutrient and carbon cycling and interact with other organisms, thereby influencing food web dynamics. The development and application of molecular methods have greatly increased the potential for unraveling the biodiversity and ecological roles of fungi in lake ecosystems. We searched the literature for reports on all fungi occurring in lake ecosystems. The present study summarizes information on the highly diverse mycoflora in lake microhabitats and highlights the main processes they influence. We also point out ecological niches of fungi in lakes that have been examined only superficially or ignored completely. We demonstrate that we now have the methodology to perform systematic studies to finally fill in some of the large gaps in this field.