Environmental factors shaping the ecological niches of ammonia-oxidizing archaea


  • Editor: Eva Top

Correspondence: Willy Verstraete, Laboratory of Microbial Ecology and Technology (LabMET), Gent University, Coupure Links 653, B-9000 Gent, Belgium. Tel.: +32 9 264 59 76; fax: +32 9 264 62 48; e-mail: willy.verstraete@ugent.be


For more than 100 years it was believed that bacteria were the only group responsible for the oxidation of ammonia. However, recently, a new strain of archaea bearing a putative ammonia monooxygenase subunit A (amoA) gene and able to oxidize ammonia was isolated from a marine aquarium tank. Ammonia-oxidizing archaea (AOA) were subsequently discovered in many ecosystems of varied characteristics and even found as the predominant causal organisms in some environments. Here, we summarize the current knowledge on the environmental conditions related to the presence of AOA and discuss the possible site-related properties. Considering these data, we deduct the possible niches of AOA based on pH, sulfide and phosphate levels. It is proposed that the AOA might be important actors within the nitrogen cycle in low-nutrient, low-pH, and sulfide-containing environments.