The Neglected Role of Heterotrophic Protists in Engineered Water Systems.
Hang Song1, Katherine Dowdell2,3, Vincent Delafont4
1Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward St, Ann Arbor, Michigan 48109, United States.
Environmental Science & Technology
|November 24, 2025
Summary
Heterotrophic protists are overlooked in engineered water systems but play vital roles. New methods reveal their functions, enabling better water treatment strategies.
Area of Science:
- Microbial Ecology
- Environmental Microbiology
- Protistology
Background:
- Heterotrophic protists are ecologically significant in natural ecosystems but understudied in engineered water systems.
- Methodological limitations have historically excluded protists from microbial analyses in engineered environments.
- Recent technological advancements are enabling comprehensive studies of protist diversity and function.
Purpose of the Study:
- To review the ecological roles of heterotrophic protists in natural environments and their translation to engineered water systems.
- To synthesize current knowledge on the beneficial roles and potential risks of protists in water treatment.
- To identify knowledge gaps and propose future research directions for protist ecology in engineered systems.
Main Methods:
- Literature review synthesizing research from protistology, microbial ecology, and environmental microbiology.
- Critical evaluation of recent studies on protist functions in various water treatment systems.
- Analysis of advances in imaging, high-throughput sequencing, and meta-omics for protist research.
Main Results:
- Heterotrophic protists perform crucial functions like nutrient cycling and predation in engineered water systems.
- Their roles in water treatment, both beneficial and potentially detrimental, are increasingly being characterized.
- Key knowledge gaps exist regarding protist dynamics and impacts in diverse engineered ecosystems.
Conclusions:
- Heterotrophic protists are essential components of engineered water microbial communities and should be integrated into ecological studies.
- Understanding protist functions is critical for developing effective and ecologically informed water management strategies.
- Future research should focus on mechanistic insights into protist roles for improved water treatment outcomes.
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