Seasonal changes in the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) within the sand of an eelgrass (
Zostera marina) zone were examined by a quantitative PCR of both crenarchaeotal and betaproteobacterial ammonia monooxygenase alpha subunit (
amoA) genes together with temperature and concentrations of ammonium, nitrite, and nitrate from May 2007 to June 2008 at Tanoura Bay, Shizuoka, Japan. The abundance of both
amoAs in the sand between May and June 2007 and between January and March 2008 was 1.5 to 2 orders of magnitude higher than the 10
4 copies g
-1 of estimated
amoA between September and December. Archaeal
amoA was more diverse than betaproteobacterial
amoA. Betaproteobacterial
amoA clone libraries were dominated by
Nitrosospira-like sequence types. An incubation experiment was conducted with sands collected in February 2008 and community structure was analyzed based on reverse-transcribed
amoAs. RNA was extracted from sand incubated for 12 days at 30°C, 17 days at 20°C, and 80 days at 10°C. Different
amoA clones were detected from
in situ sand and incubated sand. This study reveals clear evidence of seasonal change in the abundance of AOA and AOB within the sand of an eelgrass zone.
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