Both environmental and spatial variables affect bacterial functional diversity in mangrove sediments at an island scale

Abstract

Sediment microorganisms are influenced by various biotic and abiotic factors. However, information concerning the spatial factors that determine the functional diversity of sediment bacterial communities at an island scale is limited. Here, we conducted an island-scale study to assess the driving forces governing the functional diversity of sediment bacterial communities in different mangroves around the coast of Hainan Island, southern China. For mangrove sediments in Hainan Island, differences in the metabolic activity and functional diversity among four sites were context dependent, while that showed a trend of East > North > West > South. Furthermore, total carbon, nitrite nitrogen, and salinity are important environmental factors that determine the metabolic functional diversity of bacterial communities. This study also provided important insights for explaining the metabolic functional diversity of bacterial communities in tropical mangrove sediments. The metabolic activity had a significantly response to environmental variables (13.2% of pure variance was explained) and spatial variables (12.4%). More importantly, given that spatial variables may contribute to the bacterial functional as important as environmental variables, this spatial variety of bacterial functional provides new insight into studying bacterial functional biogeographic patterns and impacts on sediment-associated function.