PhD defence: Soil Protists: From Traits To Ecological Functions

The best-known function of soil protists is as bacteria feeders, protists consume bacteria prey and further release the nutrients which were locked in bacteria biomass, those nutrients benefit the remaining bacteria and plant root. Moreover, protists do not feed on all prey bacteria equally, this selective feeding by protists can lead to shifting prey bacterial community structure, which may be linked with changes in soil community functioning.

Given the lack of a generalized pattern of protists predation, the central question of this thesis is whether the effects of protist predation can be predicted. This thesis started with investigating protists traits, showing that protist predation was related to protists traits, namely, protist cell volume was informative concerning protist impacts on bacterial prey communities.

Furthermore, this thesis has shown that predation by protists can reinforce cooperation in soil, and such cooperation may be linked to positive effects on ecological functions including plant growth and plant disease suppression.