Molecular size-dependent abundance and composition of dissolved organic matter in river, lake and sea waters

Xu, Huacheng; Guo, Laodong

doi:10.1016/j.watres.2017.04.006

Cited by 200 publications

(81 citation statements)

References 62 publications

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“…As expected, the three CDOM components and SUVA 254 showed a general decrease from Groups I to II, and then to Group III, whereas S 275–295 and the bulk DOC showed an opposite trend (Figure ). These trends verify our hypothesis and also suggest that different DOM components within the bulk DOM pool clearly had different mixing behaviors and environmental fate during their estuarine mixing and offshore transport, showing a heterogeneous nature of DOM pool in aquatic environments as reported in previous studies (e.g., Stolpe et al, ; Wang et al, ; Xu & Guo, ). Using field‐flow fractionation techniques capable of simultaneous size separation and characterization, Zhou et al () also observed distinct mixing behaviors among different sized humic‐like DOM components in the Bay St. Louis‐Mississippi Sound estuarine system.…”

Section: Discussionsupporting

confidence: 91%

“…As expected, the three CDOM components and SUVA 254 showed a general decrease from Groups I to II, and then to Group III, whereas S 275-295 and the bulk DOC showed an opposite trend (Figure 8). These trends verify our hypothesis and also suggest that different DOM components within the bulk DOM pool clearly had different mixing behaviors and environmental fate during their estuarine mixing and offshore transport, showing a heterogeneous nature of DOM pool in aquatic environments as reported in previous studies (e.g., Stolpe et al, 2014;Wang et al, 2010;Xu & Guo, 2017…”

Section: Comparisons Between Surface and Bottom Layerssupporting

confidence: 91%

“…Dissolved organic matter (DOM) is heterogeneous and its changes in composition and mixing behavior at the land‐ocean interface are complex and dynamic (D'Sa et al, ; Fichot et al, ; Giraud et al, ; Seitzinger et al, ; Singh et al, ; Xu & Guo, ). Within the bulk DOM pool, individual organic components or molecular‐sized fractions have been shown to have different extents of removal or addition during estuarine mixing (Wang et al, ; Zhou et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Elucidating the Hidden Nonconservative Behavior of DOM in Large River‐Dominated Estuarine and Coastal Environments

Gao

Zong

et al. 2019

JGR Oceans

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Understanding the mixing behavior and biogeochemical cycling of heterogeneous dissolved organic matter (DOM) at the land‐ocean interface has been a major challenge, especially in large river‐dominated estuarine and coastal environments with multiple and complex end‐members of riverwater and seawater. Significant correlations and thus an “apparent” conservative behavior are generally observed for the bulk DOM when plotting concentration‐salinity relationships, but the relatively small deviations from the apparent conservative behavior are difficult to be quantified. In July 2016, the flood in the Changjiang River basin caused the Changjiang Diluted Water extended widely to the western East China Sea, making it a natural laboratory to examine the river‐sea mixing behavior of riverine DOM and other optical properties. Here a new biogeochemical approach was established to elucidate their hidden nonconservative behavior in the study area. Comparisons in the bulk dissolved organic carbon and the three chromophoric DOM properties among 13 pairs of same‐salinity patches (with similar salinities but quite different distances from the river mouth) revealed that the East China Sea shelf was a significant sink for all the three chromophoric DOM properties. The Changjiang Diluted Water surface branches transporting southward tended to serve as a sink for the bulk dissolved organic carbon while the ones transporting northward were less a sink or even a source. The different removal extents of various biogeochemical constituents can also be calculated from the same‐salinity patch comparisons. Our results obtained by the new approach provide detailed magnitudes of sink or source for different DOM properties and their in situ removal/production extents, giving new insights into biogeochemical processes in large river‐dominated estuarine and coastal environments.

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Section: Discussionsupporting

confidence: 91%

Section: Comparisons Between Surface and Bottom Layerssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Elucidating the Hidden Nonconservative Behavior of DOM in Large River‐Dominated Estuarine and Coastal Environments

Gao

Zong

et al. 2019

JGR Oceans

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“…There is little information on the size distribution of coloured DOM (CDOM) in ocean waters 43–45 . Here we observed that the aLMW fraction hosts more humic- and protein-like fluorescence intensity per carbon unit than the aHMW DOM fraction (Fig.…”

Section: Resultsmentioning

confidence: 99%

Deep-ocean dissolved organic matter reactivity along the Mediterranean Sea: does size matter?

Martínez-Pérez

Álvarez‐Salgado

Arı́stegui

2017

Sci Rep

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Despite of the major role ascribed to marine dissolved organic matter (DOM) in the global carbon cycle, the reactivity of this pool in the dark ocean is still poorly understood. Present hypotheses, posed within the size-reactivity continuum (SRC) and the microbial carbon pump (MCP) conceptual frameworks, need further empirical support. Here, we provide field evidence of the soundness of the SRC model. We sampled the high salinity core-of-flow of the Levantine Intermediate Water along its westward route through the entire Mediterranean Sea. At selected sites, DOM was size-fractionated in apparent high (aHMW) and low (aLMW) molecular weight fractions using an efficient ultrafiltration cell. A percentage decline of the aHMW DOM from 68–76% to 40–55% was observed from the Levantine Sea to the Strait of Gibraltar in parallel with increasing apparent oxygen utilization (AOU). DOM mineralization accounted for 30 ± 3% of the AOU, being the aHMW fraction solely responsible for this consumption, verifying the SRC model in the field. We also demonstrate that, in parallel to this aHMW DOM consumption, fluorescent humic-like substances accumulate in both fractions and protein-like substances decline in the aLMW fraction, thus indicating that not only size matters and providing field support to the MCP model.

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“…DOM can directly affect nutrient cycling [4], the toxicity of organic pollutants [5], the solubility of heavy metals [6] and the aquatic ecosystem [5,7], and also indirectly influence the atmospheric CO 2 level and global climate change [8,9]. It is well known that DOM is a complex mixture of natural organic compounds found in various kinds of water bodies including rivers, lakes, glaciers, and oceans [10][11][12]. …”

Section: Introductionmentioning

confidence: 99%

Seasonal Variations of Dissolved Organic Matter in the East China Sea Using EEM-PARAFAC and Implications for Carbon and Nutrient Cycling

et al. 2018

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Dissolved organic matter (DOM) plays a very important role in the dynamics of different biogeochemical processes in the global marine carbon cycle. Seasonal variations of DOM were investigated using dissolved organic carbon (DOC), absorption spectroscopy, and fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) in Niushan Island in the East China Sea, off southeast Zhejiang, in winter, spring, and summer 2017. A strong positive correlation between temperature and salinity was observed in winter, whereas negative correlations were obtained in spring and summer. The results suggest that the water in the study area originates from the Changjiang River water coinciding with the direction of winds in winter. On the other hand, the Taiwan Strait water flows northward on the eastern part of the study area in summer and spring. The DOC concentration showed significant seasonal variations and was much lower in summer than in winter, but largely independent of the temperature, degree of absorption and intensity of the fluorescence component. Three tryptophan-like components (C1, C2 and C4) and one humic-like component were identified by the PARAFAC model in winter, while two tryptophan-like components (C1 and C2) and two humic-like components were illustrated in summer. The seasonal variations of DOC concentrations and intensities of the fluorescence components in the study area from winter to summer suggest that the waters in this area were influenced mainly by mixing water of the Changjiang River and the Taiwan Strait. A strongly linear relationship was found between the nutrient and the fluorescence intensities of different components in winter, reflecting the profound impacts of the dynamics of DOM on nutrient cycling.

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Molecular size-dependent abundance and composition of dissolved organic matter in river, lake and sea waters

Cited by 200 publications

References 62 publications

Elucidating the Hidden Nonconservative Behavior of DOM in Large River‐Dominated Estuarine and Coastal Environments

Elucidating the Hidden Nonconservative Behavior of DOM in Large River‐Dominated Estuarine and Coastal Environments

Deep-ocean dissolved organic matter reactivity along the Mediterranean Sea: does size matter?

Seasonal Variations of Dissolved Organic Matter in the East China Sea Using EEM-PARAFAC and Implications for Carbon and Nutrient Cycling

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