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
<https://globalsoilbiodiversity.org/protists>*, 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