Microbial communities and specific strains within beachrocks of the South China Sea:implications for the origin of beachrock
Abundant bacterial-algal microorganisms and their metabolisms play important roles in early cementation of beachrocks along intertidal-supratidal zones of tropical-subtropical shorelands.In this study,16S rRNA high-throughput sequencing analysis was employed to reveal the compositions of prokaryotic microbial communities and identify the common strains/microbial functional groups that dominated the beachrocks'cementation.The Quanfu turf algae-bearing beachrocks have the highest biodiversity.The diversity of Longwan beachrocks in upper intertidal zone is higher than that in lower intertidal zone.The prokaryotic biodiversity of consolidated Shiyu beachrocks is the lowest.The bacterial phylum in the four sampling localities was roughly similar,which includes Proteobacteria,Bacteroideta,Actinobacteria,Cyanobacteria,Chloroflexi,Gemmatimonadetes and Desulfobacterota in descending order.The main cyanobacteria species were same.The common calcified cyanobacterial strain-Calothrix sp.was all detected,and the extracellular polymer substances could be the hotspots for precipitation of carbonate biomaterials.Denitrobacteria and sulfate-reducing bacteria detected in microbial communities indicate the anaerobic environment and steep redox gradient below the superficial beachrocks.Strong photosynthesis,sulfate reduction and denitrification in particle surface and intergranular pore together significantly rise pH,and promote the nucleation and growth of carbonate biomaterials,accelerating the consolidation of loose beach sands.
prokaryotecommunity structurecyanobacteriabeachrockSouth China Sea
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NSTL
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