Distribution of ammonia-oxidizing archaea and bacteria along an engineered coastal ecosystem in subtropical China

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the crucial players in nitrogen cycle. Both AOA and AOB were examined along a gradient of human activity in a coastal ecosystem from intertidal zone, grassland, and Casuarina equisetifolia forest to farmland. Results showed that the farmland soils had noticeably higher nitrate-N, available P than soils in the other three sites. Generally, AOA and AOB community structures varied across sites. The farmland mainly had Nitrosotalea -like AOA, intertidal zone was dominated by Nitrosopumilus AOA, while grassland and C. equisetifolia forest primarily harbored Nitrososphaera -like AOA. The farmland and C. equisetifolia forest owned Nitrosospira -like AOB, intertidal zone possessed Nitrosomonas -like AOB, and no AOB was detected in the grassland. AOA abundance was significantly greater than AOB in this coastal ecosystem ( p