Metagenomic insights into the shifts of microbial community and nitrogen-cycling genes during vegetation succession in a coastal wetland of China

The investigation was conducted in a coastal wetland on the southern shore of Hangzhou Bay, China (33°22' N, 120°42' E; Figure 1). A distinct sea-to-land vegetation succession is evident, progressing from unvegetated bare flats (BF) to stands of S. mariqueter (SM), followed by S. alterniflora (SA), and culminating in native P. australis (PA) communities, providing a well-defined environmental gradient for investigation. Sediment sampling was conducted in July 2022 across a vegetation successional gradient in the coastal wetland, encompassing BF, SM, SA, and PA communities. A spatial block design was employed, involving three parallel transects (≥300 m apart) running perpendicular to the shore. Along each transect, three plots were established for each of the four vegetation types, with adjacent community plots separated by ≥500 m.