Environmental heterogeneity mediated prokaryotic community variations in marine sediments

Abstract

Marine ecosystems have been heavily affected by environmental changes, which led to shift of prokaryotic diversity and distribution, especially in the Arctic Ocean. However, how environmental changes affect prokaryotic community still unclear. Here, prokaryotic diversity, community composition and spatial distribution patterns in marine sediments from the Bering Sea to the western Arctic Ocean were surveyed. The results indicated that the lowest bacterial and archaeal diversities were observed in the western Arctic Ocean. Moreover, the prokaryotic richness and diversity showed strong correlation (R2=0.31∼0.83, P<0.05) with heavy metals (such as Cu, Zn, Ni and As). The contents of Ni and As represented a range with in which biological effects occur occasionally in the Bering Strait, but concentrations of Cu, Zn, Ni and As in the western Arctic Ocean showed a probable effect range with in which adverse biological effects occasionally or frequently occur. Furthermore, as geographical distance increased archaeal community similarity decreased faster than bacteria. The abundances of Gammaproteobacteria, Firmicutes and Thaumarchaeota significantly increased from the Bering Sea to the western Arctic Ocean. Conversely, much lower abundances of Alphaproteobacteria, Bacteroidetes and Crenarchaeota were observed in the western Arctic Ocean. In addition, all environmental could explain 73.8% and 85.1% bacterial and archaeal variations, respectively. And heavy metals could independently explain 40.3% and 30.4% community variation for archaea and bacteria, respectively. This study emphasized effects of heavy metals on prokaryotic diversities and distribution patterns in marine sediments, which were helpful to deep understand microbial variation under environmental changes.