Spatiotemporal evolution and assembly processes of ammonia-oxidising
prokaryotic communities in 1000 years coastal reclaimed soils
Abstract
Coastal marshes are transitional areas between terrestrial and aquatic
ecosystems and vulnerable to climate change and anthropogenic
activities. In recent decades the reclamation of coastal marshes
remarkably increased and their effects on microbial communities present
in coastal marshes have been studied with great interest. However, most
of these studies focused on microbial community composition and
diversity. The processes underlying functional community assembly and
spatiotemporal effect often ignored. Therefore, community structure and
assembly mechanisms of ammonia-oxidising prokaryotes in long-term
reclaimed coastal marshes have not been studied. Here using qPCR and
IonS5TMXL sequencing platform, we investigated spatiotemporal dynamics,
assembly processes and diversity patterns in ammonia-oxidising
prokaryotes in over 1000 years reclaimed coastal salt marsh soils. The
taxonomic & phylogenetic diversity and composition of the
ammonia-oxidizers showed apparent spatiotemporal variations along
reclamation of soil. The phylogenetic null modelling-based analysis
showed across all sites, the archaeal ammonia-oxidising community
assembled by deterministic process (84.71%). The ammonia-oxidising
bacterial community was formed more by a stochastic process in coastal
marshes and at stage 60 years (|βNTI|<2),
despite its relatively dominant deterministic process (55.2%). The
deterministic assembly process and nitrification activity in reclaimed
soils was positively correlated. Archaeal amoA gene abundance were also
positively correlated with the nitrification rate. Our study revealed
that during the 1000 years of reclamation coastal marshes both
ammonia-oxidising communities responded differently to diversity change
and assembly processes and nitrification activity. These findings
provide a better understanding of how long-term reclamation affect soil
N cycling and assembly dynamics of ammonia-oxidising communities.