Spatial separation of microbial communities reflects gradients of salinity and temperature in offshore sediments from Shenzhen, south China

Abstract

The rapid industrialization and urbanization around the coastal region have resulted in a pollution pressure in Shenzhen, one of the most developed cities in China. However, microbial communities of coastal sediment and their environment quality are far from understood. Here, 16S rRNA gene sequencing was conducted to investigate the microbial community of offshore sediments from 20 coastal areas in Shenzhen and the factors affecting that variability. Results showed there was a significant difference on the diversity among the 20 sites, and notable difference between the western and eastern offshore sediments were observed. The microbial community was dominated by Nitrosopumilaceae, Flavobacteriaceae, Pirellulaceae, Woeseiaceae, Anaerolineaceae and Saprospiraceae at the family level. The abundance of Woeseia, Candidatus Nitrosopumilus, Muriicola, and Rhodopirellula were higher in samples from eastern sites, while Cyanobium PCC-6307, Acinetobacter, Sulfurovum, Robiginitalea, and Nitrospira were enriched in western sediment samples. PICRUSt-based prediction of metagenomes indicated the KEGG pathways about amino acid metabolism, carbohydrate metabolism, and energy metabolism were significantly more abundant in eastern sediments. Moreover, salinity, pH and temperature were the important environmental factors shaping the structure of microbial communities. These findings are important for understanding the relationships between bacterial communities and environmental conditions in coastal ecosystems, and provide a scientific basis for offshore ecosystem conservation.