Effects of Reclaiming Land from the Sea on the Microbial Communities of Marine Sediments

HUANG Bei;SHAO Jun-bo;Zhejiang Provincial Zhoushan Marine Ecological Environmental Monitoring Station;

land reclamation;;marine environment;;microbial community;;high throughput sequencing

Engineering construction and land reclamation have changed the natural forms of coastlines, coastal bays and estuaries, affected the hydrodynamic environment and altered seabed erosion and deposition, resulting in serious ecological problems. A petrochemical complex was planned for construction on Yushan Island of Zhoushan City and reclamation of land from the sea was carried out to create the industrial base. In this study, we analyzed the microbial community structure and spatial divergence in sediments of the marine area around the land reclamation project and identified potential links of the microbial community to environmental factors. The objective was to provide technical support for marine construction projects, coastal economic development and environmental management. In May 2016, the environmental factors and microbial communities were investigated at 10 monitoring sites, according to specifications for marine monitoring and oceanographic surveys. The marine environment was impacted by river influxes, including inputs from the Yangtze and Qiantang Rivers. Total organic carbon(TOC), petroleum, arsenic(As), cadmium(Cd), copper(Cu), and lead(Pb) were at higher levels in the northwestern area and decreased toward the east. Metagenomic analysis, using Illumina Miseq high throughput sequencing technology, identified a total of 39 phyla, 260 families and 431 genera of archaea and bacteria in the sediment samples. At the phylum level, Proteobacteria was the dominant taxa at all sampling sites, comprising 39% of the total abundance. Other abundant taxa included Actinobacteria, Acidobacteria, Chloroflexi, Bacteroidetes, and Crenarchaeota. At the genus level, Gammaproteobacteria was the dominant group and other major genera included Deltaproteobacteria, Actinomyces, Planctomyceteschus and Myxococcus. Further, Deltaproteobacteria became one of the major components of the microbial community, indicating that the study area was affected by human activities. Correlation analysis between the microbial community and environmental factors revealed that TOC, arsenic and marine benthic animals significantly affected microbial community distribution at the phylum level. The abundance of Thaumarchaeota, Lentisphaerae, and P-SR1 presented significantly negative correlations with petroleum, As, Pb and Cd.