The effect of southwest monsoon on the meso-scale biogeographic patterns of the bacteria in the northeast of South China Sea

Abstract

Complicated physical systems and strong seasonal monsoons are features of the north-east South China Sea (SCS). To understand how monsoon-driven changes affect the bacterial community structure and distribution in the surface water from shelf to slope in the northeast SCS (NESCS), we collected water samples during the intermonsoon (Spring, 2021) and Southwest monsoon (May, 2021) respectively. In our research, we found that α diversity of bacteria did not differ significantly during intermonsoon and monsoon periods, nor did it differ significantly between shelf and slope. However, bacterial community were well differentiated between groups (Shelf-I, Slope-I, Shelf-M, and Slope-M). In both seasons, there was a significant geographical distance decay relationship, but the monsoon did not change the biogeographic pattern of bacteria. Finally, all environmental factors in both seasons, except salinity, have a significant impact on bacteria, and the correlation is enhanced during the monsoon.