Diversity and community structure of bacterioplankton in surface waters off the northern tip of the Antarctic Peninsula

Abstract

Global climate change is significantly affecting marine life off the northern tip of the Antarctic Peninsula, but little is known about microbial ecology in this area. The main goal of this study was to investigate the bacterioplankton community structure in surface waters using pyrosequencing and to determine factors influencing this community. Pelagibacterales and Rhodobacterales (Alphaproteobacteria), Oceanospirillales and Alteromonadales (Gammaproteobacteria), and Flavobacteriales (Bacteroidetes) were the core taxa in our samples, and the five most relatively abundant genera were Pelagibacter, Polaribacter, Octadecabacter, group HTCC2207 and Sulfitobacter. Although nutrients and chlorophyll a (chl a) contributed more to bacterioplankton community structure than water masses or depth, only 30.39% of the variance could be explained by the investigated environmental factors, as revealed by RDA and pRDA. No significant difference with respect to nutrients and chl a was observed among water masses or depth, as indicated by ANOVA. Furthermore, significant correlations among the dominant bacterial genera were more common than correlations between dominant genera and environmental factors, as revealed by Spearman analysis. We conclude that nutrients and chl a become homogeneous and that interpopulation interactions may have a central role in influencing the bacterial community structure in surface waters off the northern tip of the Antarctic Peninsula during the summer.

Coastal Bacterial Community Response to Glacier Melting in the Western Antarctic Peninsula

“…Therefore, using this taxon as a potential sentinel should be reevaluated with further experiments to fully understand the effect of freshening on this genus. This behavior could also be explained by niche competition with other DMSP-metabolizing microorganisms, such as that previously described for Octadecabacter [ 58 ]. Additionally, another probable competitor for Sulfitobacter in Chile Bay (and WAP in general) could be the eukaryote Phaeocystis antarctica , which is a strong DMSP producer in low salinity under freezing conditions [ 75 ].…”

“…This might explain the high Polaribacter abundances found in our seawater samples during the summer of 2016, while we only detected a low abundance (<5%) in the glacier ice samples. Another dominant seawater taxon was Sulfitobacter , a Roseobacter -clade member that is considered a predominant bacterioplankton in the Antarctic Peninsula [ 58 ], and a common marine and polar sulfite oxidizer [ 59 , 60 , 61 ]. Similar to Polaribacter , the abundance of this bacterium slightly decreased as the transect became saltier.…”

“…The first was HTCC2207 (belonging to the SAR92 group, Gammaproteobacteria), which exhibited increased gene expression (3%) in the diluted experiments compared to the SW control. This Gammaproteobacteria is an important global component of the marine sulfur cycle and has been described as the most relatively abundant bacterioplankton group of the northern Antarctic Peninsula [ 58 ]. The second taxon was Pseudoalteromonas , which showed a similar pattern response to HTCC2207.…”

Deciphering a marine bone degrading microbiome reveals a complex community effort

“…Both genera are known to have an aerobic organotrophic metabolism and also able to thrive as free-living bacteria (70). In fact, the scarce representation of Oceanospirillales in the bone surface has been reported before (30, 31) and contrasts with their character as common dwellers of the marine environment (71, 72). Although we cannot rule out that Oceanospirillales preferentially colonize bone surfaces in earlier or later stages, their preference for a symbiont life supports the notion of a casual and facultative association to Osedax worms, triggered by the common benefit from a sudden nutrient bonanza as previously hypothesized (18, 21).…”

Diversity and distribution of heterotrophic flagellates in seawater of the Powell Basin, Antarctic Peninsula

“…The majority of taxa in the Rhizaria are described as predators of bacteria and small phytoplankton and have been observed in association with diatoms (Thaler & Lovejoy 2012). According to the research of Cao et al (2019) and Chen et al (2021), the bacteria community structure in station D5-8 was different from other stations. In D5-8, the dominant taxon and the proportion of the total bacterial population attributable to the dominant genus also differed from other stations.…”