PANGAEA_880926 Carbon degradation rates, sulfate reduction rates and iron composition in soils flooded with seawater at Gyldensteen Strand, Denmark Sjøgaard, Kamilla; Treusch, Alexander; Valdemarsen, Thomas Carbon degradation rates, sulfate reduction rates and iron composition in soils flooded with seawater at Gyldensteen Strand, Denmark 2017-09-25 PANGAEA Dataset Supplement to: Sjøgaard, Kamilla; Treusch, Alexander; Valdemarsen, Thomas (2017): Carbon degradation in agricultural soils flooded with seawater after managed coastal realignment. Biogeosciences, 14(18), 4375-4389, https://doi.org/10.5194/bg-14-4375-2017 https://doi.pangaea.de/10.1594/PANGAEA.880926 Earth Science geoscientificInformation Gyldensteen_Lagoon Multiple investigations Complete 55.5734 55.5734 10.1394 10.1394 unrestricted CC-BY-3.0: Creative Commons Attribution 3.0 Unported English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

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Permanent flooding of low-lying coastal areas is a growing threat due to climate change and related sea-level rise. An increasingly common solution to protect coastal areas lying below sea level is intentional flooding by "managed coastal realignment". However, the biogeochemical implications of flooding agricultural soils with seawater are still not well understood. We conducted a 1-year mesocosm experiment to investigate microbial carbon degradation processes in soils flooded with seawater. Agricultural soils were sampled on the northern coast of the island Fyn (Denmark) at Gyldensteen Strand, an area that was subsequently flooded in a coastal realignment project. We found rapid carbon degradation to TCO2 1 day after experimental flooding and onwards and microbial sulfate reduction established quickly as an important mineralization pathway. Nevertheless, no free sulfide was observed as it precipitated as Fe-S compounds with Fe acting as a natural buffer, preventing toxic effects of free sulfide in soils flooded with seawater. Organic carbon degradation decreased significantly after 6 months, indicating that most of the soil organic carbon was refractory towards microbial degradation under the anoxic conditions created in the soil after flooding. During the experiment only 6-7 % of the initial soil organic carbon pools were degraded. On this basis we suggest that most of the organic carbon present in coastal soils exposed to flooding through sea-level rise or managed coastal realignment will be permanently preserved. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.880926"! ** Data for figures 2 to 7 of Sjøgaard et al. (2017).

https://doi.org/10.5194/bg-14-4375-2017 Carbon degradation in agricultural soils flooded with seawater after managed coastal realignment DIF 9.4 2017-09-25 2026-06-26