Surface water,Elodea nuttallii and undisturbed sediment cores from the Qinshui River in Gonghu Bay were collected to carry out a simulation experiment in a laboratory to study the effect of Elodea nuttallii-immobilized nitrogen-cycling bacteria on nitrogen removal mechanisms from the river water.In this study,the transformation and fate of ammonium among four different treatment groups were investigated by using a stable ~(15)N isotope pairing technique combined with high-throughput sequencing technology [T...