An overview of meiofaunal and nematode distribution patterns in lake ecosystems differing in their trophic state

In the benthos of lakes, habitat size and structure as well as oxygen or resource availability can affect species distribution at local scales. By contrast, there is little knowledge about the mechanisms that determine the structure of benthic communities at larger scales. Here, we compiled data from the literature (23 studies monitoring 129 sites from 75 lakes located in central and northern Europe) to search for broad patterns in abundance, biomass, and community structure linked to lake trophic state (oligo-, meso-, or eutrophic), habitat features (hard vs. soft substrates), and water depth (littoral vs. profundal). The benthic meiofauna appeared much more abundant in the periphyton, and biomass was lower in oligotrophic lakes. Focusing on free-living nematodes, community structure differed markedly in hard vs soft substrates. Further, nematodes were especially dominant in profundal zones, where their diversity was significantly influenced by lake trophic state. In profundal zones of eutrophic lakes, nematode assemblages were less diverse and dominated by larger, mostly omnivorous or predacious taxa.