Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)a...Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)and the fate of reactive nitrogen remain poorly understood.In this study,the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas.The results showed that marine aquaculture significantly increased the denitrification(DNF)and dissimilatory nitrate reduction to ammonium(DNRA)rates and decreased the rate of anaerobic ammonium oxidation(ANA),as compared with non-aquaculture sites.DNF was the dominant pathway contributing to the total nitrate reduction,and its contribution to the total nitrate reduction significantly increased from 66.72%at non-aquaculture sites to 78.50%at aquaculture sites.Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes,leading to variations in the nitrate reduction rates.Although nitrate removal rates increased in the marine aquaculture area,ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times,respectively,higher than those at non-aquaculture sites.Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area,and the retained reactive nitrogen could diffuse with the tidal current to the entire bay,thereby aggravating N pollution in the entire study area.These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays.This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.展开更多
基金Acknowledgements The authors are deeply indebt to the reviwers and editors and those who helped with the tide flow observations and data collection. This research is fimded by the EC Theseus Project （Grant No. 2440104）, the National and Natural Science Foundation of China （Grant No, 41271520）, and SKLEC funds （Grant No. 2012KYYW06）.
基金supported by the National Natural Science Foundations of China(Nos.41730646,41761144062,91851111,41671007,41501524 and 41971105)the Chinese National Key Programs for Fundamental Research and Development(Nos.2016YFE0133700,and 2016YFA0600904)。
文摘Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)and the fate of reactive nitrogen remain poorly understood.In this study,the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas.The results showed that marine aquaculture significantly increased the denitrification(DNF)and dissimilatory nitrate reduction to ammonium(DNRA)rates and decreased the rate of anaerobic ammonium oxidation(ANA),as compared with non-aquaculture sites.DNF was the dominant pathway contributing to the total nitrate reduction,and its contribution to the total nitrate reduction significantly increased from 66.72%at non-aquaculture sites to 78.50%at aquaculture sites.Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes,leading to variations in the nitrate reduction rates.Although nitrate removal rates increased in the marine aquaculture area,ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times,respectively,higher than those at non-aquaculture sites.Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area,and the retained reactive nitrogen could diffuse with the tidal current to the entire bay,thereby aggravating N pollution in the entire study area.These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays.This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.
