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Functional redundancy and niche complementarity maintain nitrification stability in rapid sand filters
Alejandro Palomo1,2,3, S Jane Fowler3,4, Ibrahim M Nemer3
1State Key Laboratory of Soil Pollution Control and Safety, Southern University of Science and Technology, Shenzhen, China.
Frontiers in Microbiology
|February 6, 2026
Summary
Nitrification in drinking water filters relies on diverse ammonia oxidizers. Niche partitioning, based on factors like ammonia and temperature, allows these microbes to coexist, ensuring stable filter function despite disturbances.
Area of Science:
- Environmental microbiology
- Water treatment technologies
- Microbial ecology
Background:
- Nitrification in drinking water biofilters involves a complex community of ammonia oxidizers.
- The mechanisms enabling the coexistence of functionally redundant nitrifier groups are poorly understood.
- Understanding these mechanisms is crucial for maintaining stable drinking water treatment.
Purpose of the Study:
- To investigate the responses of co-occurring complete ammonia-oxidizing (comammox) Nitrospira, ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA) to operational disturbances.
- To elucidate the niche partitioning strategies that allow for the stable coexistence of these nitrifier groups.
- To provide a mechanistic framework for microbial coexistence in engineered ecosystems.
Main Methods:
- Utilized lab-scale columns mimicking a groundwater-fed rapid sand filter (RSF).
- Introduced operational disturbances over a 30-day period.
- Analyzed nitrifier community structure, abundance, and activity in response to varying conditions.
Main Results:
- Robust nitrification was maintained, with ammonium removal proportional to substrate loading under oxic conditions.
- Depth-dependent differentiation of nitrifier biomass was observed, with Nitrospira dominating the top layer.
- Substrate-dependent niche partitioning based on free-ammonia concentration and temperature-dependent turnover between comammox clades were evident, enabling stable coexistence.
Conclusions:
- Functional redundancy, maintained by niche complementarity among diverse nitrifier guild members, underpins the stability of RSF nitrification.
- Niche partitioning strategies, including substrate and temperature preferences, allow for the stable coexistence of comammox, AOB, and AOA.
- This study offers a mechanistic understanding of microbial coexistence in engineered oligotrophic ecosystems facing environmental fluctuations.
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