The type II methanotrophs showed distinct effects of two N
forms. The relative abundance and the absolute number of pmoA gene copies of type-II methanotrophs decreased
with increasing ammonium, indicating inhibition rather than
stimulation. In contrast, the abundance of type II methanotrophs
increased with nitrate rate . The growth occurred gradually
after nitrate application and reached a level similar to type I
methanotrophs in two weeks . DNA-SIP showed that