Temporal dynamics of carbon sequestration in coastal North Atlantic fjord system as seen through dissolved organic matter characterisation

Mathew, K. Avarachen; Ardelan, Murat Van; González, Susana Villa; Vadstein, Ôlav; Vezhapparambu, Veena Sajith; Leiknes, Øystein; Mankettikkara, Rahman; Ôlsen, Yngvar

doi:10.1016/j.scitotenv.2021.146402

Cited by 6 publications

(5 citation statements)

References 106 publications

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“…Given the results of our study, these results might also be related to an increasing contribution of DOM self-assembly. Previous studies demonstrated that biopolymers including proteins, polysaccharides, and nucleic acids are more likely to assemble into microgels. − DOM self-assembly is therefore highly dependent on DOM origin and composition and is favored in samples that were subject to microbial degradation. ,, Microbial degradation promotes the production of carboxyl-rich alicyclic molecules (CRAM) by consuming the bioavailable DOM in the euphotic layer . CRAM is an important chemical feature in PPL-extracted DOM ,, that also can facilitate aggregation and microgel formation .…”

Section: Discussionmentioning

confidence: 99%

“…60,68,69 Microbial degradation promotes the production of carboxylrich alicyclic molecules (CRAM) by consuming the bioavailable DOM in the euphotic layer. 70 CRAM is an important chemical feature in PPL-extracted DOM 20,66,71 that also can facilitate aggregation and microgel formation. 72 This general observation is in agreement with our findings that selfassembly increases the relative recovery of protein-like and microbial humic-like DOM.…”

Section: ■ Discussionmentioning

confidence: 99%

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Solid-Phase Extraction of Aquatic Organic Matter: Loading-Dependent Chemical Fractionation and Self-Assembly

Kong

Jendrossek

Ludwichowski

et al. 2021

Environ. Sci. Technol.

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Dissolved organic matter (DOM) is an important component in marine and freshwater environments and plays a fundamental role in global biogeochemical cycles. In the past, optical and molecular-level analytical techniques evolved and improved our mechanistic understanding about DOM fluxes. For most molecular chemical techniques, sample desalting and enrichment is a prerequisite. Solid-phase extraction has been widely applied for concentrating and desalting DOM. The major aim of this study was to constrain the influence of sorbent loading on the composition of DOM extracts. Here, we show that increased loading resulted in reduced extraction efficiencies of dissolved organic carbon (DOC), fluorescence and absorbance, and polar organic substances. Loading-dependent optical and chemical fractionation induced by the altered adsorption characteristics of the sorbent surface (styrene divinylbenzene polymer) and increased multilayer adsorption (DOM self-assembly) can fundamentally affect biogeochemical interpretations, such as the source of organic matter. Online fluorescence monitoring of the permeate flow allowed to empirically model the extraction process and to assess the degree of variability introduced by changing the sorbent loading in the extraction procedure. Our study emphasizes that it is crucial for sample comparison to keep the relative DOC loading (DOC load [wt %]) on the sorbent always similar to avoid chemical fractionation.

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Section: Discussionmentioning

confidence: 99%

Section: ■ Discussionmentioning

confidence: 99%

Solid-Phase Extraction of Aquatic Organic Matter: Loading-Dependent Chemical Fractionation and Self-Assembly

Kong

Jendrossek

Ludwichowski

et al. 2021

Environ. Sci. Technol.

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“…Along transect 2 across the ESS and CBL, heterotrophic bacterial abundance was higher in the ESS than in the CBL. Tryptophan-like FDOM is significantly correlated with the percent of biodegradable organic carbon (Fellman et al, 2009;Hood et al, 2009) that is rapidly consumed by bacteria in the surface waters (Rich et al, 1996;Ogawa et al, 2001;Mathew et al, 2021). Furthermore, Lønborg et al (2015) reported that the tryptophanlike FDOM decayed by 30% after 72 h of incubation in the darkness.…”

Section: Source Of Tryptophan-like Fdommentioning

confidence: 99%

“…This was supported by DeFrancesco and Gueǵuen (2021), who reported a significant increase in protein-like FDOM in the upper polar mixed layer of the central Canada Basin between 2007 and 2017. Because labile tryptophan-like FDOM is strongly correlated with the percent of biodegradable organic carbon (Fellman et al, 2009;Hood et al, 2009) that is rapidly consumed by bacteria (Rich et al, 1996;Ogawa et al, 2001;Hansell, 2013;Mathew et al, 2021), the increased supply of labile tryptophan-like FDOM is expected to provide a significant amount of biodegradable organic carbon. This, in turn, can induce changes in the quantity and quality of DOM in the Arctic Ocean.…”

Section: Potential Fate Of Fdom Under Ongoing Arctic Marine Environme...mentioning

confidence: 99%

Characterization and source of fluorescent dissolved organic matter in the Western Arctic Ocean: new insights from the 2019 summer study

et al. 2023

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Increase in river discharge and seasonal primary production and decline in sea ice coverage in the Arctic Ocean in summer can significantly affect the distribution and composition of dissolved organic matter (DOM). This study aimed to enhance the current available knowledge about the impacts of environmental changes on the characteristics of DOM in the rapidly changing Arctic Ocean. Seawater samples were collected from the western Arctic Ocean during the summer of 2019 and analyzed for fluorescent DOM (FDOM), dissolved organic carbon (DOC), and stable oxygen isotope (δ18O) content in conjunction with biophysical properties. We identified two humic-like (C1 and C2) and one protein-like (C3) components using fluorescence excitation-emission matrix coupled with parallel factor (EEM–PARAFAC) analysis. Remarkably high intensities of humic-like FDOM were found in the upper halocline layer (32 < salinity < 33.5 psu, at depths between 50–200 m) with high inorganic nutrient concentrations and low N* values, indicating that the humic-like FDOM was supplied from the shelf sediment. Furthermore, shoaling of the upper halocline layer brought high levels of humic-like FDOM to the euphotic zone, resulting in an increased probability of photodegradation of humic-like FDOM due to exposure to solar radiation in the surface layer. Tryptophan-like FDOM was positively correlated with river water fraction (friver) and riverine DOC but not with chlorophyll-a (Chl-a) and heterotrophic bacterial abundance, indicating river discharge as a potential additional source of tryptophan-like FDOM. The correlation coefficients between tryptophan-like FDOM and river water parameters (friver and riverine DOC) differed across the Chukchi Sea, Chukchi Borderland, and East Siberian Sea, implying that the influence of river discharge on tryptophan-like FDOM is region-dependent. An increase in river discharge in future might lead to a greater supply of tryptophan-like FDOM, impacting the dynamics of DOM cycling in the western Arctic Ocean.

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“…Helali et al 2016, Mathew et al 2021, Wang et al 2021a). The redox state is an important factor in the dynamics of DOM, controlling the mineralization process of organic matter and the adsorption of DOM and particles(Bastviken et al 2003, Chen &Jiang 2016).…”

mentioning

confidence: 99%

Effect of redox conditions on the release of dissolved organic matter and nutrients at the sediment-water interface and the role of microbes

Bao

Wang

et al. 2022

Preprint

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The dynamics of nutrients are closely related to microbial activities and substantially influenced by the redox conditions. This study conducted an incubation experiment on sediment under different redox conditions. Concentrations of dissolved organic carbon (DOC), nitrogen, and phosphorus were measured to investigate the release of nutrients from the sediment. An excitation-emission matrix and PARAFAC analysis were used to characterize dissolved organic matter (DOM). The structure of microbes and functional genes were analyzed via high-throughput sequencing and real-time polymerase chain reaction. Oxic conditions decreased the NH4+ and NO2− concentrations and reduced the increases in total nitrogen and DOC concentrations. Oxic conditions also exhibited a higher alpha diversity index and microbial community abundance. Regarding functional genes, the expression levels of nitrification genes (amoA) increased under all redox conditions, especially under oxic and original conditions, which explained the removal of ammonia nitrogen. Higher expression levels of nitrite-reducing genes (nirK and nirS) were found in oxic environments owing to the abundant NO3− supply. The expression of the anammox gene (hzo) is stimulated in anoxic environments, which contributes to the lack of oxygen and a higher concentration of NH4+.

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Temporal dynamics of carbon sequestration in coastal North Atlantic fjord system as seen through dissolved organic matter characterisation

Cited by 6 publications

References 106 publications

Solid-Phase Extraction of Aquatic Organic Matter: Loading-Dependent Chemical Fractionation and Self-Assembly

Solid-Phase Extraction of Aquatic Organic Matter: Loading-Dependent Chemical Fractionation and Self-Assembly

Characterization and source of fluorescent dissolved organic matter in the Western Arctic Ocean: new insights from the 2019 summer study

Effect of redox conditions on the release of dissolved organic matter and nutrients at the sediment-water interface and the role of microbes

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