Impact of water quality variations on the microbial metagenome across coastal waters in Shenzhen, south China

Abstract

Shenzhen is a coastal city in south China that has developed rapidly over the past four decades, but the microbial diversity and functions of the coastal waters are still not well characterized. Here, we assessed spatial variability of water quality and microbial communities in four areas of Shenzhen coast. The results showed a significant difference on the microbial composition and function between water samples from eastern coast and western coast. The abundance of Rhodobacteraceae bacterium HIMB11, Candidatus Pelagibacter ubique, and alpha proteobacterium HIMB59 were significantly higher in eastern waters (p < 0.01), while Candidatus Aquiluna sp. IMCC13023 and Arcobacter butzleri were more abundant in western samples. Functional analysis of the metagenome indicated there were 504,613 genes on average in each sample. Eastern samples harbored more family genes that classify into glycosyl transferases, carbohydrate esterases, auxiliary activities and polysaccharide lyases compared to western samples. Moreover, KEGG pathways including amino acid metabolism, carbohydrate metabolism, and energy metabolism were enriched in eastern coastal waters. The total nitrogen, total phosphorus, chemical oxygen demand, and number of harmful marine vibrio were significantly higher in western coast, suggesting water quality may have impact on the microbial alteration. The findings anticipate future development of effective indicators of coastal health monitoring and subsequent management strategies to control the anthropogenic disturbance in the Shenzhen coastal waters.