Abstract
The disturbance and relocation of coastal sediments by human activities constitutes a potentially large disruption to natural sediment and organic carbon fluxes, but large-scale estimates of these impacts are lacking. Here, we estimate the amounts of sediment and organic carbon disturbed and relocated in the North Sea resulting from (1) dredging in the form of mineral aggregate extraction and (2) material dumping during waterway maintenance. We show that despite disturbing less sediment than aggregate extraction, dumping causes greater carbon disturbance. We estimate carbon disturbance by both activities to be higher than by marine construction, but lower than by bottom-contacting fisheries. Simulations indicate that most dumped material re-deposits near the coast. Gl…
Abstract
The disturbance and relocation of coastal sediments by human activities constitutes a potentially large disruption to natural sediment and organic carbon fluxes, but large-scale estimates of these impacts are lacking. Here, we estimate the amounts of sediment and organic carbon disturbed and relocated in the North Sea resulting from (1) dredging in the form of mineral aggregate extraction and (2) material dumping during waterway maintenance. We show that despite disturbing less sediment than aggregate extraction, dumping causes greater carbon disturbance. We estimate carbon disturbance by both activities to be higher than by marine construction, but lower than by bottom-contacting fisheries. Simulations indicate that most dumped material re-deposits near the coast. Globally, dumping of organic carbon is estimated to 0.09–0.46 GtC yr−1, and disturbance by material extraction to 0.04−0.08 GtC yr−1. Comparison to natural processes suggests that these activities should be considered in regional to global sediment and carbon budgets.
Data availability
Extracted areas and amounts available at “EMODnet Human Activities, Aggregate Extraction” https://ows.emodnet-humanactivities.eu/geonetwork/srv/api/records/fde45abd-7bf3-4f05-869c-d1ce77f4ac63?language=all-4f05-869c-d1ce77f4ac63, “Effects of extraction of marine sediments on the marine environment 2005-2011” https://doi.org/10.17895/ices.pub.5498, and “Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT)” https://doi.org/10.17895/ices.pub.5733. Dumped amounts available at “OSPAR Dumping and Placement of Wastes or Other Matter at Sea” https://odims.ospar.org/en/submissions/ospar_dumping_at_sea_2021_01/. Modelled OC pools of different reactivities are available at “Field and Model Data for Bottom Trawling Impacts in the North Sea” https://doi.org/10.5281/zenodo.8297751. “Wadden Sea World Heritage Site” polygons available at http://marineregions.org/mrgid/26877. Source data for Fig. 2 and Fig. 3b are provided with this paper. Source data are provided with this paper.
Code availability
The SCHISM model including the sediment module is available at https://doi.org/10.5281/zenodo.6537526. The TOCMAIM model is available at https://doi.org/10.17632/2vvny3xd85.2.
References
Dunne, J. P., Sarmiento, J. L. & Gnanadesikan, A. A synthesis of global particle export from the surface ocean and cycling through the ocean interior and on the seafloor. Global Biogeochem. Cycles https://doi.org/10.1029/2006GB002907 (2007).
Tegler, L. A. et al. Distribution and drivers of organic carbon sedimentation along the continental margins. AGU Adv. 5, e2023AV001000 (2024).
Legge, O. et al. Carbon on the Northwest European shelf: contemporary budget and future influences. Front. Marine Sci. https://doi.org/10.3389/fmars.2020.00143 (2020).
Colina Alonso, A. et al. A mud budget of the Wadden Sea and its implications for sediment management. Commun. Earth Environ. 5, 153 (2024).
Syvitski, J. P. M., Vörösmarty, C. J., Kettner, A. J. & Green, P. Impact of Humans on the flux of terrestrial sediment to the global coastal Ocean. Science 308, 376–380 (2005).
Bianchi, T. S. et al. Anthropogenic impacts on mud and organic carbon cycling. Nat. Geosci. 17, 287–297 (2024).
Zhang, H. et al. Global changes alter the amount and composition of land carbon deliveries to European rivers and seas. Commun. Earth Environ. 3, 245 (2022).
Regnier, P. et al. Anthropogenic perturbation of the carbon fluxes from land to ocean. Nat. Geosci. 6, 597–607 (2013).
Grasso, F., Bismuth, E. & Verney, R. Unraveling the impacts of meteorological and anthropogenic changes on sediment fluxes along an estuary-sea continuum. Sci. Rep. 11, 20230 (2021).
Mazarrasa, I., Garcia-Orellana, J., Puente, A. & Juanes, J. A. Coastal engineering infrastructure impacts Blue Carbon habitats distribution and ecosystem functions. Sci. Rep. 12, 19352 (2022).
Bauer, J. E. et al. The changing carbon cycle of the coastal ocean. Nature 504, 61–70 (2013).
Mathis, M. et al. Enhanced CO2 uptake of the coastal ocean is dominated by biological carbon fixation. Nat. Clim. Change 14, 373–379 (2024).
Atwood, T. B. et al. Atmospheric CO2 emissions and ocean acidification from bottom-trawling. Front. Mar. Sci. https://doi.org/10.3389/fmars.2023.1125137 (2024).
Paradis, S. et al. Contrasting particle fluxes and composition in a submarine canyon affected by natural sediment transport events and bottom trawling. Front. Mar. Sci. https://doi.org/10.3389/fmars.2022.1017052 (2022).
Zhang, W. et al. Long-term carbon storage in shelf sea sediments reduced by intensive bottom trawling. Nat. Geosci. 17, 1268–1276 (2024).
Epstein, G., Middelburg, J. J., Hawkins, J. P., Norris, C. R. & Roberts, C. M. The impact of mobile demersal fishing on carbon storage in seabed sediments. Glob Change Biol. 28, 2875–2894 (2022).
Keil, R. Anthropogenic Forcing of Carbonate and Organic Carbon Preservation in Marine Sediments. Annu. Rev. Mar. Sci. 9, 151–172 (2017).
Kenny, A. J. et al. Assessing cumulative human activities, pressures, and impacts on North Sea benthic habitats using a biological traits approach. ICES J. Mar. Sci. 75, 1080–1092 (2018).
Todd, V. L. G. et al. A review of impacts of marine dredging activities on marine mammals. ICES J. Mar. Sci. 72, 328–340 (2015).
Bonthond, G. et al. Benthic microbial biogeographic trends in the North Sea are shaped by an interplay of environmental drivers and bottom trawling effort. ISME Commun. 3, 132 (2023).
Common Wadden Sea Secretariat (CWSS). Report on the State of Conservation of the World Heritage property “The Wadden Sea (N1314)”, https://www.waddensea-worldheritage.org/2024-report-state-conservation-world-heritage-property-wadden-sea-n1314 (2024). 1.
Stive, M. J. et al. A new alternative to saving our beaches from sea-level rise:the sand engine. J. Coas. Res. 29, 1001–1008 (2013). 1.
Bockelmann, F.-D., Puls, W., Kleeberg, U., Müller, D. & Emeis, K.-C. Mapping mud content and median grain-size of North Sea sediments – A geostatistical approach. Mar. Geol. 397, 60–71 (2018).
Porz, L. et al. Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea. Biogeosciences 21, 2547–2570 (2024).
Sanches, L. F., Guenet, B., Marino, N. D. A. C. & de Assis Esteves, F. Exploring the Drivers Controlling the Priming Effect and Its Magnitude in Aquatic Systems. J. Geophys. Res. Biogeosci. 126, e2020JG006201 (2021).
European Dredging Association (EuDA). Annual Report 2023, https://european-dredging.eu/pdf/EuDA_23.pdf (2023). 1.
Benninghoff, M. & Winter, C. Recent morphologic evolution of the German Wadden Sea. Sci. Rep. 9, 9293 (2019).
Hein, J. & Hilder, N. Estuarine territorialization and the port of Hamburg. *Marit. Stud.*22, 39 (2023).
Gebert, J. & Zander, F. Aerobic and anaerobic mineralisation of sediment organic matter in the tidal River Elbe. J. Soils Sediments 24, 2874–2886 (2024).
Zander, F., Heimovaara, T. & Gebert, J. Spatial variability of organic matter degradability in tidal Elbe sediments. J. Soils Sediments 20, 2573–2587 (2020).
Heinatz, K. & Scheffold, M. I. E. A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea. Front. Mar. Sci. https://doi.org/10.3389/fmars.2022.1068967 (2023).
Clare, M. A., Lichtschlag, A., Paradis, S. & Barlow, N. L. M. Assessing the impact of the global subsea telecommunications network on sedimentary organic carbon stocks. *Nat. Commun.*14, 2080 (2023).
Thomas, H. et al. The carbon budget of the North Sea. Biogeosciences 2, 87–96 (2005).
Maavara, T., Lauerwald, R., Regnier, P. & van Cappellen, P. Global perturbation of organic carbon cycling by river damming. Nat. Commun. 8, 15347 (2017).
Cooper, A. H., Brown, T. J., Price, S. J., Ford, J. R. & Waters, C. N. Humans are the most significant global geomorphological driving force of the 21st century. Anthr. Rev. 5, 222–229 (2018).
Syvitski, J. P. & Kettner, A. Sediment flux and the Anthropocene. Philos. Trans. R. Soc. A Math. Phys. Eng. Sci. 369, 957–975 (2011).
Torres, A., Jouffray, J.-B., van Lancker, V., Velpen, A. V. & Liu, J. Reducing sand mining’s growing toll on marine biodiversity. One Earth 8, 101202 (2025).
Chen, F. et al. Assessing the global flux of organic carbon transported from terrestrial surfaces to oceans by rivers. Carbon Balance Manag. 20, 29 (2025).
Hofstede, J. L. A. & Stock, M. Climate change adaptation in the Schleswig-Holstein sector of the Wadden Sea: an integrated state governmental strategy. J. Coastal Conserv. 22, 199–207 (2018).
Cronin, M., Judd, A., Blake, S. & Lonsdale, J. Assessment of Data on the Management of Wastes or Other Matter (Dredged Material) 2008 - 2020. In The 2023 Quality Status Report for the North-East Atlantic (London, 2023). 1.
Watson, S. J. et al. The footprint of ship anchoring on the seafloor. Sci. Rep. 12, 7500 (2022).
Feldens, P., Schwarzer, K., Sakuna-Schwartz, D. & Khokiattiwong, S. Geomorphological evolution of the Andaman Sea offshore Phang Nga Province (Thailand) during the Holocene: an example for a sediment starving shelf. Coasts https://doi.org/10.3390/coasts2010001 (2022).
Frankignoulle, M., Canon, C. & Gattuso, J.-P. Marine calcification as a source of carbon dioxide: Positive feedback of increasing atmospheric CO2. Limnol. Oceanogr. 39, 458–462 (1994).
Dauvin, J.-C., Baux, N. & Lesourd, S. Benthic impact assessment of a dredge sediment disposal in a dynamic resilient environment. Mar. Pollut. Bull. 179, 113668 (2022).
Stronkhorst, J. et al. Environmental impact and recovery at two dumping sites for dredged material in the North Sea. Environ. Pollution 124, 17–31 (2003).
Palanques, A., Guillén, J., Puig, P. & Durán, R. Effects of long-lasting massive dumping of dredged material on bottom sediment and water turbidity during port expansion works. Ocean Coastal Manag. 223, 106113 (2022).
Kalapurakkal, H. T. et al. Sediment resuspension in muddy sediments enhances pyrite oxidation and carbon dioxide emissions in Kiel Bight. Commun. Earth Environ. 6, 156 (2025).
van de Velde, S. J., Hylén, A. & Meysman, F. J. R. Ocean alkalinity destruction by anthropogenic seafloor disturbances generates a hidden CO2 emission. Sci. Adv. 11, eadp9112 (2025).
Koplin, J. et al. Blue Carbon potential in Germany: Status and future development. Estuar. Coast. Shelf S. 323, 109354 (2025).
Macreadie, P. I. et al. Blue carbon as a natural climate solution. Nat. Rev. Earth Environ. 2, 826–839 (2021).
Bertram, C. et al. The blue carbon wealth of nations. Nat. Clim. Change 11, 704–709 (2021).
ICES. Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT). ICES Sci. Rep. https://doi.org/10.17895/ices.pub.5733 (2019). 1.
Spearman, J. A review of the physical impacts of sediment dispersion from aggregate dredging. Mar. Pollut. Bull. 94, 260–277 (2015).
Newell, R., Hitchcock, D. & Seiderer, L. Organic enrichment associated with outwash from marine aggregates dredging: a probable explanation for surface sheens and enhanced benthic production in the vicinity of dredging operations. Marine Pollut. Bull. 38, 809–818 (1999).
AZTI. EMODnet Human activities, aggregate extraction (rev. of 2023-09-15). Available at https://ows.emodnet-humanactivities.eu/geonetwork/srv/api/records/fde45abd-7bf3-4f05-869c-d1ce77f4ac63?language=all-4f05-869c-d1ce77f4ac63 (2014). 1.
Walker, R. et al. Effects of extraction of marine sediments on the marine environment 2005-2011. ICES Cooperative Research Reports (CRR), https://doi.org/10.17895/ices.pub.5498,01.01.2016 (2016). 1.
OSPAR Commission (OSPAR). Dumping and placement of wastes or other matter at sea. data source: OSPAR data and information management system. Available at https://odims.ospar.org/en/submissions/ospar_dumping_at_sea_2021_01/ (2021). 1.
Zander, F., Groengroeft, A., Eschenbach, A., Heimovaara, T. J. & Gebert, J. Organic matter pools in sediments of the tidal Elbe river. Limnologica 96, 125997 (2022).
Siham, K., Fabrice, B., Edine, A. N. & Patrick, D. Marine dredged sediments as new materials resource for road construction. Waste Manag. 28, 919–928 (2008).
Verlaan, P. Marine vs Fluvial Bottom Mud in the Scheldt Estuary. Estuar. Coast. Shelf S. 50, 627–638 (2000).
Zhang, W. et al. The Budget of Macrobenthic Reworked Organic Carbon: A Modeling Case Study of the North Sea. J. Geophys. Res. Biogeosci. 124, 1446–1471 (2019).
Daewel, U. & Schrum, C. Simulating long-term dynamics of the coupled North Sea and Baltic Sea ecosystem with ECOSMO II: Model description and validation. J. Mar. Sys. 119-120, 30–49 (2013).
Birchenough, S. N., Boyd, S. E., Vanstaen, K., Coggan, R. A. & Limpenny, D. S. Mapping an aggregate extraction site off the Eastern English Channel: A methodology in support of monitoring and management. Estuar. Coast. Shelf S. 87, 420–430 (2010).
Kenny, A. J. & Rees, H. L. The effects of marine gravel extraction on the macrobenthos: Results 2 years post-dredging. Marine Pollut. Bull. 32, 615–622 (1996).
Zhang, Y. J., Ye, F., Stanev, E. V. & Grashorn, S. Seamless cross-scale modeling with SCHISM. Ocean Model. 102, 64–81 (2016).
Kossack, J., Mathis, M., Daewel, U., Zhang, Y. J. & Schrum, C. Barotropic and baroclinic tides increase primary production on the Northwest European Shelf. Front. Mar. Sci. https://doi.org/10.3389/fmars.2023.1206062 (2023).
Chen, J. et al. Physical Mechanisms of Sediment Trapping and Deposition on Spatially Confined Mud Depocenters in High-Energy Shelf Seas. J. Geophys. Res. Oceans 130, e2025JC022622 (2025).
Winterwerp, J. C. On the flocculation and settling velocity of estuarine mud. Cont. Shelf Res. 22, 1339–1360 (2002).
Gundlach, J. et al. Simulating the near-field dynamic plume behavior of disposed fine sediments. Front. Mar. Sci. https://doi.org/10.3389/fmars.2024.1416521 (2024).
Maerz, J. et al. Maximum sinking velocities of suspended particulate matter in a coastal transition zone. Biogeosciences 13, 4863–4876 (2016).
Gerritsen, H., Boon, J., van der Kaaij, T. & Vos, R. Integrated Modelling of Suspended Matter in the North Sea. Estuar. Coast. Shelf S. 53, 581–594 (2001).
McCave, I. N. Mud in the North Sea. In North Sea Science, edited by E. D. Goldberg (MIT Press, Cambridge, Mass., 1973). 1.
Eisma, D. Supply and Deposition of Suspended Matter in the North Sea. In Holocene Marine Sedimentation in the North Sea Basin, edited by S. Nio, R. Shüttenhelm & T. Van Weering, 415–428 (1981). 1.
Diesing, M., Thorsnes, T. & Bjarnadóttir, L. R. Organic carbon densities and accumulation rates in surface sediments of the North Sea and Skagerrak. Biogeosciences 18, 2139–2160 (2021).
Acknowledgements
This study is a contribution to the project APOC funded by the German Federal Ministry of Education and Research (BMBF) within the MARE:N programme (grant 03F0874C; L.P., J.C., W.Z., R.Y., and J.K.) and to the collaborative project KomSO (grant 3523NK370A-E; L.P., W.Z., J.K.) coordinated by the German Federal Agency for Nature Conservation (BfN). It is also supported by the Helmholtz research programme POF IV “The Changing Earth – Sustaining our Future” within “Topic 4: Coastal zones at a time of global change”. This work used resources of the German Climate Computing Centre (DKRZ) granted by its Scientific Steering Committee (WLA) under project ID bg1244.
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Open Access funding enabled and organized by Projekt DEAL.
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Authors and Affiliations
Institute of Coastal Systems, Helmholtz-Zentrum Hereon, Max-Planck-Strasse 1, Geesthacht, Germany
Lucas Porz, Jiayue Chen, Ruemeysa Yilmaz, Wenyan Zhang & Corinna Schrum 1.
BUND-Meeresschutzbüro, Bund für Umwelt und Naturschutz Deutschland e.V. (BUND), Bremen, Germany
Jannis Kuhlmann 1.
Institute of Oceanography, Center for Earth System Research and Sustainability, Universität Hamburg, Bundesstrasse 53, Hamburg, Germany
Corinna Schrum
Authors
- Lucas Porz
- Jiayue Chen
- Ruemeysa Yilmaz
- Jannis Kuhlmann
- Wenyan Zhang
- Corinna Schrum
Contributions
Funding acquisition: W.Z., C.S., and L.P.; Technical implementation: L.P., J.C., and W.Z.; Data analysis: L.P., R.Y., and J.K.; Writing: L.P.; Editing: L.P., W.Z., R.Y., J.C., J.K., and C.S.
Corresponding authors
Correspondence to Lucas Porz or Wenyan Zhang.
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Nature Communications thanks Evgeny Ivanov, Sebastiaan Van De Velde, and the other anonymous reviewers for their contribution to the peer review of this work. A peer review file is available.
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Porz, L., Chen, J., Yilmaz, R. et al. Dredging and dumping impact coastal fluxes of sediment and organic carbon. Nat Commun (2026). https://doi.org/10.1038/s41467-025-68105-5
Received: 11 February 2025
Accepted: 17 December 2025
Published: 07 January 2026
DOI: https://doi.org/10.1038/s41467-025-68105-5