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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Biogeochemistry
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1433199

Qualitative variability of Dissolved Organic Matter in the Baltic Sea sediments apparent from fluxes and optical properties

Provisionally accepted
Alexandra N. Loginova Alexandra N. Loginova 1*Urban J. Wünsch Urban J. Wünsch 2Monika Zabłocka Monika Zabłocka 1Aleksandra Cherkasheva Aleksandra Cherkasheva 1Beata Szymczycha Beata Szymczycha 1Karol Kulinski Karol Kulinski 1Aleksandra Winogradow Aleksandra Winogradow 1Piotr Kowalczuk Piotr Kowalczuk 1
  • 1 Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
  • 2 National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark

The final, formatted version of the article will be published soon.

    The release of dissolved organic matter (DOM) from sediments serves as an important part of the carbon cycle. Here, we address pore water DOM quality and its release from shallow sediments (0-10 cm) of the central and southern Baltic Sea, Gdansk, Bornholm, and Eastern Gotland Basins, using Excitation Emission Matrix spectroscopy and size exclusion chromatography. DOM release from sediments displayed spatial variability, with diffusive DOC fluxes ranging from 0.02 to 1.06 mmol m-2 d-1, and basin-averaged fluxes increased in order Gotland< Bornholm< Gdansk. DOM qualitative characteristics also varied among investigated basins. In the oxygen-limited study sites from the Gdansk Basin, we observed elevated abundancies of low apparent molecular weight DOM fraction and proteinaceous-like fluorescent DOM, while in the Bornholm Basin, pore water DOM was generally more humic-like and of higher apparent molecular weight. Pore waters from the deepest study sites in the Gotland Basin were qualitatively very similar to those of the pore waters from the upper sediment layers (0-4 cm) from all other investigated sites, suggesting little organic matter reworking at depth in those stations. Our results suggest that the spatial variability in the magnitude of DOM release may be linked to the qualitative differences of DOM in sediments.

    Keywords: dissolved organic matter, porewater DOM, DOM molecular weight, Sediment release, Baltic Sea, FDOM

    Received: 05 Jun 2024; Accepted: 15 Aug 2024.

    Copyright: © 2024 Loginova, Wünsch, Zabłocka, Cherkasheva, Szymczycha, Kulinski, Winogradow and Kowalczuk. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Alexandra N. Loginova, Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland

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