Dynamic changes in size‐fractionated dissolved organic matter composition in a seasonally ice‐covered Arctic River

Lin, Hui; Xu, Huacheng; Cai, Yihua; Belzile, Claude; Macdonald, R. W.; Guo, Laodong

doi:10.1002/lno.11862

Cited by 26 publications

(8 citation statements)

References 74 publications

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“…Average FRESH index values are similar to those found in thawed permafrost and in other small high-latitude rivers in Alaska (Mutschlecner et al, 2018;Selvam et al, 2017). BIX values observed in the Onega are lower than those described for the Yukon River, which has BIX values consistent with high inputs of terrestrial DOM (Lin et al, 2021), signifying even greater relative inputs in the Onega. Taken together, all the CDOM parameters highlight that DOM in the Onega River has a highly terrestrial contribution.…”

Section: Comparisons Between the Onega River And Other Arctic Fluvial...supporting

confidence: 69%

Characterizing Uncertainty in Pan‐Arctic Land‐Ocean Dissolved Organic Carbon Flux: Insights From the Onega River, Russia

et al. 2023

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Dissolved organic carbon (DOC) flux from rivers in the pan‐Arctic watershed represents an important connection between major terrestrial carbon stocks and the Arctic Ocean. Previous estimates of Arctic carbon flux and dissolved organic matter (DOM) seasonal dynamics have relied predominantly on measurements from the six major Arctic rivers, yet these may not be representative of northern high‐latitude constrained smaller watersheds. Here, we evaluate DOC concentration and DOM composition in the Onega River, a small Arctic watershed, using optical measurements and ultrahigh resolution mass spectrometry. Compared to the six largest Arctic rivers, DOC, absorbance at a350, and indicators of terrestrial DOM (e.g., specific UV absorbance at 254 nm, modified aromaticity index, relative abundance of condensed aromatics and polyphenolics) were elevated in the Onega throughout the year. Seasonality was also generally muted in comparison to the major Arctic rivers with relatively elevated DOC and terrestrial markers in both spring and fall seasons. The Onega exhibits a strong relationship between a350 and DOC, and its organic‐rich nature is apparent in its high DOC yield (4.85 g m2yr−1), and higher chromophoric DOM per unit DOC than the six largest Arctic rivers. As DOC yield from the Onega may be more representative of smaller northern high‐latitude rivers, we derived a new pan‐Arctic DOC flux scaling estimate which is over 50% higher than previous estimates scaled solely from the six major Arctic rivers. These observations suggest that smaller northern high‐latitude rivers may be underrepresented in Arctic carbon flux models and highlights uncertainty around constraining the export of DOC to the Arctic Ocean.

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Section: Comparisons Between the Onega River And Other Arctic Fluvial...supporting

confidence: 69%

Characterizing Uncertainty in Pan‐Arctic Land‐Ocean Dissolved Organic Carbon Flux: Insights From the Onega River, Russia

et al. 2023

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“…Compared with traditional correlation analysis between characterization indices (Figure ) or molecular linkages (C–H, CC, C–O, C–N, etc. ), our results (the multivariate analysis) associate each molecule with characterization parameters and reveal a more precise and comprehensive cognition of the DOM characteristics in urban stormwater runoff. In addition, compared with traditional one-way correlation analysis (correlated only optical parameters to the mass spectrometer molecules), correlations analysis leads to two results (optical and molecular signatures) mutually verified, thereby effectively reducing the contingency of individual characterization results.…”

Section: Benefits and Limitationsmentioning

confidence: 71%

Insights into the Associations between Optical and Molecular Signatures of Dissolved Organic Matter from Urban Stormwater Runoff

et al. 2022

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Modern fluorescence techniques are widely employed to determine the dissolved organic matter (DOM) fluorescent components and quality in urban stormwater runoff. However, its molecular basis is still poorly defined, leading to unclear and unspecific interpretations of fluorescence characterization. This research focused on the correlation analysis between optical and molecular signatures of DOM. The optical parameters are effectively correlated with the individual molecules detected by mass spectrometry. Moreover, molecular characterization parameters are also associated with three-dimensional fluorescence spectroscopy in reverse. Through nonmetric multidimensional scaling (NMDS), the fluorescence indices tracing the source of DOM are effectively categorized and verified by molecular characteristics. Meanwhile, Spearman rank correlation analysis indicated that humic-like components derived from microbial-and tryptophan-like compositions are associated with aromaticity; however, terrestrial humic-like constituents are closely correlated with H/C, O/C, and N/C ratios. In addition, the molecular mechanism of four fluorescent components indicated that the nitrogen (N)-containing components, reduced constituents, and aliphatic compounds are resistant to degradation, while the oxidized and aromatic components are preferentially removed. Those signatures observed for individual molecules are consistent with the bulk characteristics of DOM, as reflected by optical properties.

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“…FDOM was employed as a proxy for DOM to study the dynamic changes in DOM composition [ 56 ]. The FDOM components were characterized with three-dimensional EEM spectroscopy coupled with the PARAFAC analysis technique, and total EEM collection of the algal-derived dissolved organic matter; its different molecular fractions and lake water were modeled with PARAFAC using MATLAB with the DOMFluor toolbox.…”

Section: Resultsmentioning

confidence: 99%

New Insights into Microbial Degradation of Cyanobacterial Organic Matter Using a Fractionation Procedure

Chen

Zhou

Zhang

2022

IJERPH

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Cyanobacterial blooms caused by phytoplankton Microcystis have occurred successively since 1980 in Lake Taihu, China, which has led to difficulty collecting clean drinking water. The effects of cyanobacterial scum-derived dissolved organic matter (DOM) on microbial population variations and of algal-derived filtrate and algal residual exudative organic matter caused by the fraction procedure on nutrient mineralization are unclear. This study revealed the microbial-regulated transformation of DOM from a high-molecular-weight labile to a low-molecular-weight recalcitrant, which was characterized by three obvious stages. The bioavailability of DOM derived from cyanobacterial scum by lake microbes was investigated during 80-d dark degradation. Carbon substrates provided distinct growth strategy links to the free-living bacteria abundance variation, and this process was coupled with the regeneration of different forms of inorganic nutrients. The carryover effects of Microcystis cyanobacteria blooms can exist for a long time. We also found the transformation of different biological availability of DOM derived from two different cyanobacterial DOM fractions, which all coupled with the regeneration of different forms of inorganic nutrients. Our study provides new insights into the microbial degradation of cyanobacterial organic matter using a fractionation procedure, which suggests that the exudate and lysate from degradation products of cyanobacteria biomass have heterogeneous impacts on DOM cycling in aquatic environments.

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Dynamic changes in size‐fractionated dissolved organic matter composition in a seasonally ice‐covered Arctic River

Cited by 26 publications

References 74 publications

Characterizing Uncertainty in Pan‐Arctic Land‐Ocean Dissolved Organic Carbon Flux: Insights From the Onega River, Russia

Characterizing Uncertainty in Pan‐Arctic Land‐Ocean Dissolved Organic Carbon Flux: Insights From the Onega River, Russia

Insights into the Associations between Optical and Molecular Signatures of Dissolved Organic Matter from Urban Stormwater Runoff

New Insights into Microbial Degradation of Cyanobacterial Organic Matter Using a Fractionation Procedure

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