Abstract: To explore the effects of heavy metals to microbial community structures of mangrove sediment, surface and rhizosphere sediment samples were collected from Futian National Reserve, Shenzhen Bay Mangrove Park, Baguang Mangrove Reserve, and Mai Po Reserve. The contents of Cr, Ni, Cu, Zn and Pb were analyzed, with the pollution levels of which being evaluated by Pollution Load Index (PLI). Microbial assemblages were profiled using 16S rRNA highthroughput sequencing and OTUs data were analyzed using cluster analysis, α diversity analysis (Shannon Index), and Spearman correlation analysis. There were significant differences in heavy metal contents among different sampling sites. Mai Po Reserve had the most severe pollution of heavy metals, with PLI of 1.51 in mud flat and 1.38 in mangrove forest. The other three sampling sites were less polluted, with PLI of 0.45 in Futian Reserve, 0.31 in Shenzhen Bay Mangrove Park, and 0.21 in Baguang Reserve. The four sites had no significant differences in microbial community structure, with predominance of Proteobackteria, Chloroflexi, Actinobacteria, Bacteroidetes, and Firmicutes at phylum level, as well as Gammaproteobacteria, Alphaproteobacteria, Deltaproteobacteria, Anaerolineae, Betaproteobacteria at class level. Multivariate analyses revealed that there were no statistically significant correlations between metal pollutions and microbial community structure across different sites. Results from Spearman correlation analyses indicated that heavy metal contents influenced the within habitat diversity of some phylum and class such as phylum BRC1 and class Epsilonproteobacteria.

Key words: photosynthetic characteristic, PSⅡ photochemical activity, sesame/peanut intercropping, intercropping advantage on yield, PSⅠ photochemical activity