30 Questions for Soil Protistology

Image from S. Geisen

By Stefan Geisen, Department of Terrestrial Ecology & Laboratory of Nematology, Netherlands Institute of Ecology, Wageningen, The Netherlands



With 47 authors of the soil protist initiative, a group closely linked to the GSBI, we have just compiled an important opinion paper to highlight 30 key open study questions dealing with soil protists. We show that protists are a highly-underrepresented group of soil organisms, especially compared with the other microbial bacteria and fungi. However, there are several reasons why protists are important and should be prioritized or at least be included in future soil biodiversity studies!





Protists are incredibly diverse!

  • Protists are taxonomically highly diverse; they represent the majority of the eukaryotic tree of life where fungi, plants and animals are small monophyletic groups.
  • We also highlight that protists are morphologically diverse, ranging from bacterial sized taxa of few micrometers to several centimeters.
  • Furthermore, protists span a huge functional diversity of organisms; in addition to the mainly considered bacterivorous taxa, many protists feed on fungi, nematodes, a huge diversity is parasitic to animals and pathogenic in plants.


Protists are of key importance in soils!

  • Without protists, bacteria and fungi would have few enemies!
  • Protists are a key link in soil food webs- without them most soil animals had no food!
  • Without protists, plants would suffer from nutrient limitation!

Fig. 1. Common free-living soil protists as visualized by size (lengths), morphology and phylogenetic affiliation
Modified from Geisen et al. 2017

This is just a fraction of what we highlight in the paper. For more info, check out the paper published in Soil Biology and Biochemistry. More updates on the soil protist initiative can also be accessed directly at https://soilprotists.wordpress.com/ and https://www.researchgate.net/project/Soil-protist-initiative.


Don’t hesitate to get in touch with us and be connected- protists are a key part of future research!