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<p>The Siberian Arctic Shelf is experiencing rapid environmental change, driven by climate warming that is amplified in the Northern Hemisphere. A key consequence is mobilization of dissolved organic matter (DOM) from permafrost thaw and associated landscape degradation. In this study, we explore the molecular composition and optical properties of DOM across three Arctic Shelf regions: the Kara Sea (KS), Laptev Sea (LS), and East Siberian Sea (ESS). We developed a two-dimensional classification framework linking the optical properties of shelf water (absorbance and fluorescence) with DOM molecular composition (ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry [FT-ICR MS]) to trace DOM sources on the Arctic Shelf. A strong inverse correlation between SUVA<sub>254</sub> (specific ultraviolet absorbance at 254 nm) and Asm<sub>280</sub> (emission band asymmetry at 280 nm), i.e., <i>R</i><sup>2</sup> = 0.82, revealed a compositional continuum from highly aromatic DOM in KS and LS to more aliphatic, labile DOM in marine-influenced ESS waters. Molecular analysis confirmed this trend: DOM in KS and LS was enriched in hydrolyzable and condensed tannins, CARF (Core Arctic Riverine Fingerprint), and IOS (Island of Stability) formulae. In contrast, ESS and Arctic offshore DOM showed higher contributions of more saturated lignin-, terpenoid-, and carbohydrate-like compounds. The occupation densities of Van Krevelen diagrams attributed to the aromatics populated domain (D7), and the combined aliphatic/carbohydrate-like domain (D14 +  D15) served as robust molecular predictors of DOM optical behavior. Their inverse relationship (<i>R</i><sup>2</sup> = 0.72) provided additional resolution for classifying DOM sources across regions. This integrated framework demonstrates the utility of combining optical and molecular techniques for tracking DOM composition and reactivity under changing Arctic hydroclimatic conditions.</p> Graphical abstract <p></p>

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Arctic shelf water can be categorized by sampling site linking its optical parameters and molecular composition of SPE-DOM

  • 期刊论文

  • 发表日期：

    2026年2月16日

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  • Anna N. Khreptugova,
  • Kirill V. Petrov,
  • Galina S. Pechnikova,
  • Evgeny A. Shirshin,
  • Dmitry S. Volkov,
  • Alexander B. Volikov,
  • Igor P. Semiletov,
  • Irina V. Perminova

摘要

The Siberian Arctic Shelf is experiencing rapid environmental change, driven by climate warming that is amplified in the Northern Hemisphere. A key consequence is mobilization of dissolved organic matter (DOM) from permafrost thaw and associated landscape degradation. In this study, we explore the molecular composition and optical properties of DOM across three Arctic Shelf regions: the Kara Sea (KS), Laptev Sea (LS), and East Siberian Sea (ESS). We developed a two-dimensional classification framework linking the optical properties of shelf water (absorbance and fluorescence) with DOM molecular composition (ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry [FT-ICR MS]) to trace DOM sources on the Arctic Shelf. A strong inverse correlation between SUVA254 (specific ultraviolet absorbance at 254 nm) and Asm280 (emission band asymmetry at 280 nm), i.e., R2 = 0.82, revealed a compositional continuum from highly aromatic DOM in KS and LS to more aliphatic, labile DOM in marine-influenced ESS waters. Molecular analysis confirmed this trend: DOM in KS and LS was enriched in hydrolyzable and condensed tannins, CARF (Core Arctic Riverine Fingerprint), and IOS (Island of Stability) formulae. In contrast, ESS and Arctic offshore DOM showed higher contributions of more saturated lignin-, terpenoid-, and carbohydrate-like compounds. The occupation densities of Van Krevelen diagrams attributed to the aromatics populated domain (D7), and the combined aliphatic/carbohydrate-like domain (D14 +  D15) served as robust molecular predictors of DOM optical behavior. Their inverse relationship (R2 = 0.72) provided additional resolution for classifying DOM sources across regions. This integrated framework demonstrates the utility of combining optical and molecular techniques for tracking DOM composition and reactivity under changing Arctic hydroclimatic conditions.

Graphical abstract