Abstract
The V3–V4 hypervariable regions of the 16S ribosomal RNA gene were analyzed to assess prokaryotic diversity and community compositions within 19 surface sediment samples collected from three different regions (depth: 250–3,548 m) of Prydz Bay, the Antarctic Peninsula region, and the Ross Sea. In our results, we characterized 1,079,709 clean tag sequences representing 43,227 operational taxonomic units (OTUs, 97% similarity). The prokaryotic community distribution exhibited obvious geographical differences, and the sequences formed three distinct clusters according to the samples’ origins. In general, the biodiversity of Prydz Bay was higher than those of the Antarctic Peninsula region and the Ross Sea, and there were similar prokaryotic communities in different geographic locations. The most dominant clades in the prokaryotic communities were Proteobacteria, Bacteroidetes, Thaumarchaeota, Oxyphotobacteria, Deinococcus-Thermus, Firmicutes, Acidobacteria, Fusobacteria, and Planctomycetes, but unique prokaryotic community compositions were found in each of the sampling regions. Our results also demonstrated that the prokaryotic diversity and community distribution were mainly influenced by geographical and physicochemical factors, such as Zn, V, Na, K, water depth, and especially geographical distance (longitude variation of sample location) and Ba ion content. Moreover, geochemical factors such as nutrient contents (TC, P, and Ca) also played important roles in prokaryotic diversity and community distribution. This represents the first report that Ba ion content has an obvious effect on prokaryotic diversity and community distribution in Southern Ocean sediments.
Highlights
Antarctica is arguably the world’s most important continent for influencing the Earth’s climate and ocean ecosystem function (Wilkins et al, 2012)
Relatively few studies have been conducted on prokaryotic diversity in sediments, especially deep-sea sediments, from the Southern Ocean using high-throughput sequencing (HTS) technology
The contents of total carbon (TC), total organic carbon (TOC), and total nitrogen (TN) differed among the three regions, these differences did not reach statistical significance
Summary
Antarctica is arguably the world’s most important continent for influencing the Earth’s climate and ocean ecosystem function (Wilkins et al, 2012). In recent years, increasing evidence based on large-scale spatial comparisons has revealed far greater complexity in the biogeographic patterns of terrestrial ecosystems of Antarctica than was previously appreciated (Chown and Convey, 2007; Convey et al, 2008; Terauds et al, 2012) These studies showed that strongly localized diversity was detected when comparing the genetic lineages of Antarctic microbial eukaryotic organisms across different locations (Lawley et al, 2004; Namsaraev et al, 2010). Knowledge about the relationship between both the diversity and distribution of prokaryote in surface sediments and geophysicochemical factors of sediments in the Southern Ocean remain limited
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