Response of bacterial communities from Kongsfjorden (Svalbard, Arctic Ocean) to macroalgal polysaccharide amendments

Jain, Anand; Krishnan, K. P.; Begum, Nazira; Singh, Archana; Thomas, Femi Anna; Gopinath, Anu

doi:10.1016/j.marenvres.2020.104874

Cited by 21 publications

(13 citation statements)

References 85 publications

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“…These results are well matched with those of Lachnit et al (2013), where artificial hydrogel surfaces hosted significantly different microbial communities from those of Fucus vesiculosus after 3 days in the field, with abundant Epsilonproteobacteria and Gammaproteobacteria on artificial substrates. The same families of Gammaproteobacteria reported here, including Colwelliaceae and Pseudoalteromonadaceae, were enriched in seawater amended with alginate and agarose in the Arctic Ocean (Jain et al, 2020), suggesting that polysaccharides Fig 2. A. Microbial community structure of each sample type visualized with a non-metric multidimensional scaling (NMDS) plot. Each point represents one microbial community sample, and points clustered more closely together have more similar microbial communities.…”

Section: Resultssupporting

confidence: 68%

“…(2013), where artificial hydrogel surfaces hosted significantly different microbial communities from those of Fucus vesiculosus after 3 days in the field, with abundant Epsilonproteobacteria and Gammaproteobacteria on artificial substrates. The same families of Gammaproteobacteria reported here, including Colwelliaceae and Pseudoalteromonadaceae , were enriched in seawater amended with alginate and agarose in the Arctic Ocean (Jain et al ., 2020), suggesting that polysaccharides such as agarose may select for common microbial taxa in the seawater, even in different ocean basins.…”

Section: Resultsmentioning

confidence: 99%

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Oxygen metabolism shapes microbial settlement on photosynthetic kelp blades compared to artificial kelp substrates

Weigel

Pfister

2020

Environ Microbiol Rep

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Summary We examined factors shaping community assembly of the bull kelp (Nereocystis luetkeana) microbiome by comparing microbial biofilm formation on photosynthetic kelp blade tissues and artificial kelp substrates (‘agar substrates’) deployed into a kelp forest. New kelp blade tissues were colonized by markedly distinct microbial taxa relative to agar substrates during the same time interval, even when agar substrates were infused with N. luetkeana blades, suggesting that microbial settlement onto kelp surfaces is more than just attraction to a polysaccharide‐rich surface. Further, common seawater taxa such as Colwellia sp. and Psychromonas sp. became abundant on agar substrates but avoided new kelp blade tissues, indicating that host‐specific factors may deter certain surface‐associated marine microbial taxa. Over two‐thirds of the bacterial taxa in the kelp microbiome were associated with strictly aerobic metabolisms; thus, photosynthetic production of O2 may favour aerobic microbial metabolisms. While living kelp blades primarily recruited aerobic microbes, including the obligate aerobe Granulosicoccus sp., microbes that colonized agar substrates were predominantly facultative anaerobes. We also found that infusion of kelp tissues into agar substrates altered microbial community composition and lowered taxonomic diversity relative to control agar substrates, suggesting that non‐living components of the kelp blade also impact microbial community assembly.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Oxygen metabolism shapes microbial settlement on photosynthetic kelp blades compared to artificial kelp substrates

Weigel

Pfister

2020

Environ Microbiol Rep

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“…Given the post-phytoplankton bloom conditions and higher δ 13 C values in AdW, marine DOC derived from phytoplankton likely represented an additional, autochthonous source of DOC in June. Phytoplankton blooms are known to trigger bacterial succession (e.g., Teeling et al, 2012;Chafee et al, 2018;Jain et al, 2020;Manna et al, 2020). In fact, we did observe several taxa attributed to spring-bloom successions (e.g., Polaribacter, discussed below).…”

Section: Terrestrial Inputs Shape Changes In Pelagic Microbial Communmentioning

confidence: 60%

Terrestrial Inputs Shape Coastal Bacterial and Archaeal Communities in a High Arctic Fjord (Isfjorden, Svalbard)

et al. 2021

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The Arctic is experiencing dramatic changes including increases in precipitation, glacial melt, and permafrost thaw, resulting in increasing freshwater runoff to coastal waters. During the melt season, terrestrial runoff delivers carbon- and nutrient-rich freshwater to Arctic coastal waters, with unknown consequences for the microbial communities that play a key role in determining the cycling and fate of terrestrial matter at the land-ocean interface. To determine the impacts of runoff on coastal microbial (bacteria and archaea) communities, we investigated changes in pelagic microbial community structure between the early (June) and late (August) melt season in 2018 in the Isfjorden system (Svalbard). Amplicon sequences of the 16S rRNA gene were generated from water column, river and sediment samples collected in Isfjorden along fjord transects from shallow river estuaries and glacier fronts to the outer fjord. Community shifts were investigated in relation to environmental gradients, and compared to river and marine sediment microbial communities. We identified strong temporal and spatial reorganizations in the structure and composition of microbial communities during the summer months in relation to environmental conditions. Microbial diversity patterns highlighted a reorganization from rich communities in June toward more even and less rich communities in August. In June, waters enriched in dissolved organic carbon (DOC) provided a niche for copiotrophic taxa including Sulfitobacter and Octadecabacter. In August, lower DOC concentrations and Atlantic water inflow coincided with a shift toward more cosmopolitan taxa usually associated with summer stratified periods (e.g., SAR11 Clade Ia), and prevalent oligotrophic marine clades (OM60, SAR92). Higher riverine inputs of dissolved inorganic nutrients and suspended particulate matter also contributed to spatial reorganizations of communities in August. Sentinel taxa of this late summer fjord environment included taxa from the class Verrucomicrobiae (Roseibacillus, Luteolibacter), potentially indicative of a higher fraction of particle-attached bacteria. This study highlights the ecological relevance of terrestrial runoff for Arctic coastal microbial communities and how its impacts on biogeochemical conditions may make these communities susceptible to climate change.

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“…Wietz et al [ 32 ] showed that the addition of 0.001% soluble alginate to seawater from the Patagonian continental shelf induced a strong increase in Alteromonadaceae that could reach 80% final relative abundance. Similar alginate amendment to Arctic seawater favored a few Bacteroidia and Gammaproteobacteria , including Polaribacter and Colwellia [ 30 ]. Alginate particles added to coastal surface seawater from California [ 31 ] or Massachusetts [ 29 ] also induced the growth of Bacteroidetes and Alteromonadales , including Psychromonas .…”

Section: Discussionmentioning

confidence: 99%

Isotopic tracing reveals single-cell assimilation of a macroalgal polysaccharide by a few marine Flavobacteria and Gammaproteobacteria

Thomas

Duff

et al. 2021

The ISME Journal

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Algal polysaccharides constitute a diverse and abundant reservoir of organic matter for marine heterotrophic bacteria, central to the oceanic carbon cycle. We investigated the uptake of alginate, a major brown macroalgal polysaccharide, by microbial communities from kelp-dominated coastal habitats. Congruent with cell growth and rapid substrate utilization, alginate amendments induced a decrease in bacterial diversity and a marked compositional shift towards copiotrophic bacteria. We traced 13C derived from alginate into specific bacterial incorporators and quantified the uptake activity at the single-cell level, using halogen in situ hybridization coupled to nanoscale secondary ion mass spectrometry (HISH-SIMS) and DNA stable isotope probing (DNA-SIP). Cell-specific alginate uptake was observed for Gammaproteobacteria and Flavobacteriales, with carbon assimilation rates ranging from 0.14 to 27.50 fg C µm−3 h−1. DNA-SIP revealed that only a few initially rare Flavobacteriaceae and Alteromonadales taxa incorporated 13C from alginate into their biomass, accounting for most of the carbon assimilation based on bulk isotopic measurements. Functional screening of metagenomic libraries gave insights into the genes of alginolytic Alteromonadales active in situ. These results highlight the high degree of niche specialization in heterotrophic communities and help constraining the quantitative role of polysaccharide-degrading bacteria in coastal ecosystems.

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Response of bacterial communities from Kongsfjorden (Svalbard, Arctic Ocean) to macroalgal polysaccharide amendments

Cited by 21 publications

References 85 publications

Oxygen metabolism shapes microbial settlement on photosynthetic kelp blades compared to artificial kelp substrates

Oxygen metabolism shapes microbial settlement on photosynthetic kelp blades compared to artificial kelp substrates

Terrestrial Inputs Shape Coastal Bacterial and Archaeal Communities in a High Arctic Fjord (Isfjorden, Svalbard)

Isotopic tracing reveals single-cell assimilation of a macroalgal polysaccharide by a few marine Flavobacteria and Gammaproteobacteria

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