Bacterial community structure in intertidal sediments of Fildes Peninsula, maritime Antarctica

The Fildes Peninsula has a maritime Antarctic climate and has attracted the interest of scientists for decades. The soil bacterial community and the environmental factors shaping it have been well documented. However, the bacterial community of intertidal sediments, which has been determined to play crucial roles in biogeochemical cycles in temperate regions, has been comparatively neglected. Here, the diversity and abundance of bacteria in intertidal sediments represented by 18 samples from the Fildes Peninsula were revealed by 16S rRNA gene pyrosequencing and qPCR. The results showed distinct bacterial community structure, and lower diversity and abundance relative to low-latitude areas. Proteobacteria, Bacteroidetes, and Actinobacteria were the predominant phyla, accounting for similar to 90 % of the total community. Among the measured environmental factors, chlorophyll a (Chl a), total organic matter (TOM), and standard deviation (sigma) of sediment grain size explained the bacterial community variation in the redundancy analysis across all samples, and had consistent relationship with bacterial diversity and abundance. Granulosicoccus, the most abundant genus within Chromatiales Gammaproteobacteria in this study, showed positive correlation with standard deviation of sediment grain size. The present study demonstrated a distinct bacterial community different from temperate regions and provided insights into the potential ecological roles of specific taxa in the Antarctic environment.