Bacterial community dynamics during polysaccharide degradation at contrasting sites in the Southern and Atlantic Oceans

Abstract

The bacterial degradation of polysaccharides is central to marine carbon cycling, but little is known about the bacterial taxa that degrade specific marine polysaccharides. Here, bacterial growth and community dynamics were studied during the degradation of the polysaccharides chitin, alginate and agarose in microcosm experiments at four contrasting locations in the Southern and Atlantic Oceans. At the Southern polar front, chitin-supplemented microcosms were characterized by higher fractions of actively growing cells and a community shift from Alphaproteobacteria to Gammaproteobacteria and Bacteroidetes. At the Antarctic ice shelf, chitin degradation was associated with growth of Bacteroidetes, with 24% higher cell numbers compared with the control. At the Patagonian continental shelf, alginate and agarose degradation covaried with growth of different Alteromonadaceae populations, each with specific temporal growth patterns. At the Mauritanian upwelling, only the alginate hydrolysis product guluronate was consumed, coincident with increasing abundances of Alteromonadaceae and possibly cross-feeding SAR11. 16S rRNA gene amplicon libraries indicated that growth of the Bacteroidetes-affiliated genus Reichenbachiella was stimulated by chitin at all cold and temperate water stations, suggesting comparable ecological roles over wide geographical scales. Overall, the predominance of location-specific patterns showed that bacterial communities from contrasting oceanic biomes have members with different potentials to hydrolyse polysaccharides.

Major changes in the composition of a Southern Ocean bacterial community in response to diatom-derived dissolved organic matter

“…Flavobacteria are known to be efficient degraders of complex polymers, such as polysaccharides, proteins or chitin, and tend to be less active than other bacterial groups in taking up simple sugars or amino acids González et al 2008;Straza et al 2010;Simon et al 2012;Wietz et al 2015;Fourquez et al 2016). These characteristics are supported by proteomic and genomic studies showing that Flavobacteria possess numerous genes involved in hydrolytic activities as well as high molecular weight compounds transporters such as TonB-dependent receptors, and comparatively low numbers of genes involved in the uptake of low molecular weight compounds (González et al 2008;Gómez-Pereira et al 2012;Fernández-Gómez et al 2013;Williams et al 2013).…”

An alternative polysaccharide uptake mechanism of marine bacteria

“…The ability to use polysaccharides has been confirmed for many marine bacterial phyla, including Bacteroidetes , Planctomycetes , Verrucomicrobia and Proteobacteria (Martinez-Garcia et al , 2012; Teeling et al , 2012; Kabisch et al , 2014; Lage and Bondoso, 2014; Wietz et al , 2015). Based on the literature (Schattenhoffer et al , 2009; Teeling et al , 2012; Lage and Bondoso, 2014; Wietz et al , 2015) and cell morphologies, a selection of group-specific FISH probes (Supplementary Table S1) was used to identify and enumerate specific bacterial group abundances at each time point and station.…”

Microbial Surface Colonization and Biofilm Development in Marine Environments

“…Studies have shown that Bacteroidetes bacteria are common in marine environments (791), abundant in organic particle-rich coastal waters (108,113,130,611,791), responsive to algal and jellyfish blooms (272,537,756,(791)(792)(793), copiotrophic (252), and prone to leading a surface-associated life (12,17,246,272,574,607) supported by the extracellular degradation of complex biopolymers such as polysaccharides and proteins (194,791,(794)(795)(796)(797). These bacteria harbor a large number of genes for adhesive exopolysaccharides, adhesion proteins, proteases, peptidases, glycoside hydrolases, and lipases, and several genes for biopolymer degradation are coregulated with the genes for TonBdependent transport systems (794,795,(798)(799)(800)(801)(802).…”