Biochemical composition of particles shape particle-attached bacterial community structure in a high Arctic fjord

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

doi:10.1016/j.ecolind.2019.03.015

Cited by 27 publications

(28 citation statements)

References 69 publications

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“…As also observed in Kongsfjorden (Calleja et al, 2017), low δ 13 C values were found alongside steep spectral slopes at the longer wavelengths (S 350−400 ) and low S R (Figure 6), both indications of high molecular weight terrestrial material (Weishaar et al, 2003;Helms et al, 2008). On the other hand, Jain et al (2019), suggest that low δ 13 C values can also be observed for marine POC on Svalbard, where increased lipids (which are depleted in 13 C) due to the presence of cryophytes in the water column, lead to lower δ 13 C values in the POM. While cryptophytes and other lipid-rich plankton were present in the water column in June, 2018 (pers.…”

Section: Seasonal Changes In Source and Quality Of Organic Matter In supporting

confidence: 67%

“…Surprisingly, while δ 13 C-POC values from river samples ranged from −24 to −28 , estuary and outer fjord stations had values as low as −30.5 in June, 2018. Studies in Kongsfjorden have also reported similarly low δ 13 C values for POC (Kędra et al, 2012;Calleja et al, 2017;Jain et al, 2019), which no clear explanation. We suggest that the low δ 13 C-POC values here could represent the finer organic fraction of terrestrial POC transported farther from glacial fronts and river outlets, or the transport of material from diffuse runoff, coastal erosion and sediment resuspension in the nearshore (Zajączkowski, 2008).…”

Section: Seasonal Changes In Source and Quality Of Organic Matter In mentioning

confidence: 94%

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Terrestrial Inputs Drive Seasonality in Organic Matter and Nutrient Biogeochemistry in a High Arctic Fjord System (Isfjorden, Svalbard)

et al. 2020

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Climate-change driven increases in temperature and precipitation are leading to increased discharge of freshwater and terrestrial material to Arctic coastal ecosystems. These inputs bring sediments, nutrients and organic matter (OM) across the landocean interface with a range of implications for coastal ecosystems and biogeochemical cycling. To investigate responses to terrestrial inputs, physicochemical conditions were characterized in a river-and glacier-influenced Arctic fjord system (Isfjorden, Svalbard) from May to August in 2018 and 2019. Our observations revealed a pervasive freshwater footprint in the inner fjord arms, the geochemical properties of which varied spatially and seasonally as the melt season progressed. In June, during the spring freshet, rivers were a source of dissolved organic carbon (DOC; with concentrations up to 1410 µmol L −1). In August, permafrost and glacial-fed meltwater was a source of inorganic nutrients including NO 2 + NO 3 , with concentrations 12-fold higher in the rivers than in the fjord. While marine OM dominated in May following the spring phytoplankton bloom, terrestrial OM was present throughout Isfjorden in June and August. Results suggest that enhanced land-ocean connectivity could lead to profound changes in the biogeochemistry and ecology of Svalbard fjords. Given the anticipated warming and associated increases in precipitation, permafrost thaw and freshwater discharge, our results highlight the need for more detailed seasonal field sampling in small Arctic catchments and receiving aquatic systems.

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Section: Seasonal Changes In Source and Quality Of Organic Matter In supporting

confidence: 67%

Section: Seasonal Changes In Source and Quality Of Organic Matter In mentioning

confidence: 94%

Terrestrial Inputs Drive Seasonality in Organic Matter and Nutrient Biogeochemistry in a High Arctic Fjord System (Isfjorden, Svalbard)

et al. 2020

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“…This particle‐associated vs. bulk polysaccharide hydrolase difference in spectrum has been observed at various sites and depths in the central Arctic (Balmonte et al ) and in the North Atlantic (D'Ambrosio et al ). Moreover, carbohydrate content of particulate matter in fjords may shape particle‐associated bacterial community structure, selecting for taxa that are likely capable of biopolymer degradation (Jain et al ). Thus, particle‐associated microbial taxa, compared to their free‐living counterparts, may be equipped with a broader spectrum of hydrolytic enzymes that can hydrolyze high‐molecular‐weight components of particles, and likely contribute to the degradation and utilization of specific compounds transported from glacial catchments to the fjord.…”

Section: Discussionmentioning

confidence: 99%

“…The role that particulate matter play in shaping microbial community composition and carbon remineralization also remains largely unidentified in high latitude fjords (Sperling et al ; Osterholz et al ; Jain et al ). Studies from other aquatic environments demonstrate that particles can host bacterial communities with distinct composition (DeLong et al ; Schmidt et al ) and function (Fernandez‐Gomez et al ; D'Ambrosio et al ) compared to their free‐living counterparts.…”

mentioning

confidence: 99%

“…Furthermore, the composition of particle‐associated bacterial communities differs across river‐to‐ocean gradients (Crump et al ; Ortega‐Retuerta et al ; Bižić‐Ionescu et al ), although functional differences between particle‐associated taxa in freshwater and marine environments are not well understood (Simon et al ). Analyses of sinking particulate matter and sediments in fjords show evidence of both terrestrial and marine origins (Rysgaard and Sejr ; Bourgeois et al ; Cui et al ), suggesting that glacial discharge has the potential to shape microbial community structure in fjords through particle transport (Bhatia et al ; Overeem et al ; Jain et al ). Indeed, estimates show that up to 90% of OM from the Greenland Ice Sheet is in particulate form (Bhatia et al ).…”

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confidence: 99%

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Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord

Balmonte

Hasler-Sheetal

Glud

et al. 2019

Limnology & Oceanography

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Increasing glacial discharge can lower salinity and alter organic matter (OM) supply in fjords, but assessing the biogeochemical effects of enhanced freshwater fluxes requires understanding of microbial interactions with OM across salinity gradients. Here, we examined microbial enzymatic capabilities—in bulk waters (nonsize‐fractionated) and on particles (≥ 1.6 μm)—to hydrolyze common OM constituents (peptides, glucose, polysaccharides) along a freshwater–marine continuum within Tyrolerfjord‐Young Sound. Bulk peptidase activities were up to 15‐fold higher in the fjord than in glacial rivers, whereas bulk glucosidase activities in rivers were twofold greater, despite fourfold lower cell counts. Particle‐associated glucosidase activities showed similar trends by salinity, but particle‐associated peptidase activities were up to fivefold higher—or, for several peptidases, only detectable—in the fjord. Bulk polysaccharide hydrolase activities also exhibited freshwater–marine contrasts: xylan hydrolysis rates were fivefold higher in rivers, while chondroitin hydrolysis rates were 30‐fold greater in the fjord. Contrasting enzymatic patterns paralleled variations in bacterial community structure, with most robust compositional shifts in river‐to‐fjord transitions, signifying a taxonomic and genetic basis for functional differences in freshwater and marine waters. However, distinct dissolved organic matter (DOM) pools across the salinity gradient, as well as a positive relationship between several enzymatic activities and DOM compounds, indicate that DOM supply exerts a more proximate control on microbial activities. Thus, differing microbial enzymatic capabilities, community structure, and DOM composition—interwoven with salinity and water mass origins—suggest that increased meltwater may alter OM retention and processing in fjords, changing the pool of OM supplied to coastal Arctic microbial communities.

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Insights into the bacterial community composition of farmed Caulerpa lentillifera: A comparison between contrasting health states

et al. 2021

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The bacterial communities of Caulerpa lentillifera were studied during an outbreak of an unknown disease in a sea grape farm from Vietnam. Clear differences between healthy and diseased cases were observed at the order, genus, and Operational Taxonomic Unit (OTU) level. A richer diversity was detected in the diseased thalli of C. lentillifera , as well as the dominance of the orders Flavobacteriales (phylum Bacteroidetes) and Phycisphaerales (Planctomycetes). Aquibacter, Winogradskyella , and other OTUs of the family Flavobacteriaceae were hypothesized as detrimental bacteria, this family comprises some well‐known seaweed pathogens. Phycisphaera together with other Planctomycetes and Woeseia were probably saprophytes of C. lentillifera . The Rhodobacteraceae and Rhodovulum dominated the bacterial community composition of healthy C. lentillifera . The likely beneficial role of Bradyrhizobium, Paracoccus , and Brevundimonas strains on nutrient cycling and phytohormone production was discussed. The bleaching of diseased C. lentillifera might not only be associated with pathogens but also with an oxidative response. This study offers pioneering insights on the co‐occurrence of C. lentillifera ‐attached bacteria, potential detrimental or beneficial microbes, and a baseline for understanding the C. lentillifera holobiont. Further applied and basic research is urgently needed on C. lentillifera microbiome, shotgun metagenomic, metatranscriptomic, and metabolomic studies as well as bioactivity assays are recommended.

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Biochemical composition of particles shape particle-attached bacterial community structure in a high Arctic fjord

Cited by 27 publications

References 69 publications

Terrestrial Inputs Drive Seasonality in Organic Matter and Nutrient Biogeochemistry in a High Arctic Fjord System (Isfjorden, Svalbard)

Terrestrial Inputs Drive Seasonality in Organic Matter and Nutrient Biogeochemistry in a High Arctic Fjord System (Isfjorden, Svalbard)

Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord

Insights into the bacterial community composition of farmed Caulerpa lentillifera: A comparison between contrasting health states

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