Articles | Volume 22, issue 23
https://doi.org/10.5194/bg-22-7929-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-22-7929-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Dec 2025
Research article |
| 11 Dec 2025
| 11 Dec 2025
Bioaccumulation as a driver of high MeHg in the North and Baltic Seas
David J. Amptmeijer
CORRESPONDING AUTHOR
Matter Transport and Ecosystem Dynamics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Elena Mikheeva
Matter Transport and Ecosystem Dynamics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Ute Daewel
Matter Transport and Ecosystem Dynamics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Johannes Bieser
Matter Transport and Ecosystem Dynamics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Corinna Schrum
Matter Transport and Ecosystem Dynamics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Universität Hamburg, Institute for Marine Sciences, Mittelweg 177, 20146 Hamburg, Germany
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David J. Amptmeijer, Andrea Padilla, Sofia Modesti, Corinna Schrum, and Johannes Bieser
Biogeosciences, 22, 7483–7503, https://doi.org/10.5194/bg-22-7483-2025, https://doi.org/10.5194/bg-22-7483-2025, 2025
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This paper combines a literature review with a 1D Hg speciation and bioaccumulation model to assess how feeding strategy affects inorganic and methylmercury at the base of marine food webs. We find filter feeders have higher MeHg, while suspension feeders have very low MeHg, highlighting feeding strategy as a key driver of MeHg variability.
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The mercury (Hg) form of most concern is monomethylmercury (MMHg⁺) due to its neurotoxicity and ability to bioaccumulate in seafood. Bioaccumulation in seafood occurs via bioconcentration (direct uptake) and biomagnification (trophic transfer). Our study separates these processes, showing that bioconcentration increases MMHg⁺ in high trophic level fish by 15 % per level, contributing 28–49 % of MMHg⁺ in Atlantic cod. These findings can be used to inform efficient Hg modeling strategies.
David Johannes Amptmeijer, Ulrike Hanz, Corinna Schrum, and Johannes Bieser
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Sponges have unusually low methylmercury (MeHg) and high inorganic mercury (iHg) bioaccumulation compared to other macrobenthos. This pattern has been attributed to MeHg demethylation by symbiotic bacteria. Our model demonstrates an alternative explanation that dissolved organic matter (DOM) consumption by sponges can increase iHg and decrease MeHg levels. Low MeHg in sponges at the food web base may further limit MeHg bioaccumulation in higher trophic levels.
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This paper combines a literature review with a 1D Hg speciation and bioaccumulation model to assess how feeding strategy affects inorganic and methylmercury at the base of marine food webs. We find filter feeders have higher MeHg, while suspension feeders have very low MeHg, highlighting feeding strategy as a key driver of MeHg variability.
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The mercury (Hg) form of most concern is monomethylmercury (MMHg⁺) due to its neurotoxicity and ability to bioaccumulate in seafood. Bioaccumulation in seafood occurs via bioconcentration (direct uptake) and biomagnification (trophic transfer). Our study separates these processes, showing that bioconcentration increases MMHg⁺ in high trophic level fish by 15 % per level, contributing 28–49 % of MMHg⁺ in Atlantic cod. These findings can be used to inform efficient Hg modeling strategies.
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EGUsphere, https://doi.org/10.5194/egusphere-2025-5377, https://doi.org/10.5194/egusphere-2025-5377, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
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Sponges have unusually low methylmercury (MeHg) and high inorganic mercury (iHg) bioaccumulation compared to other macrobenthos. This pattern has been attributed to MeHg demethylation by symbiotic bacteria. Our model demonstrates an alternative explanation that dissolved organic matter (DOM) consumption by sponges can increase iHg and decrease MeHg levels. Low MeHg in sponges at the food web base may further limit MeHg bioaccumulation in higher trophic levels.
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Danilo Custódio, Katrine Aspmo Pfaffhuber, T. Gerard Spain, Fidel F. Pankratov, Iana Strigunova, Koketso Molepo, Henrik Skov, Johannes Bieser, and Ralf Ebinghaus
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Stefano Galmarini, Paul Makar, Olivia E. Clifton, Christian Hogrefe, Jesse O. Bash, Roberto Bellasio, Roberto Bianconi, Johannes Bieser, Tim Butler, Jason Ducker, Johannes Flemming, Alma Hodzic, Christopher D. Holmes, Ioannis Kioutsioukis, Richard Kranenburg, Aurelia Lupascu, Juan Luis Perez-Camanyo, Jonathan Pleim, Young-Hee Ryu, Roberto San Jose, Donna Schwede, Sam Silva, and Ralf Wolke
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This technical note presents the research protocols for phase 4 of the Air Quality Model Evaluation International Initiative (AQMEII4). This initiative has three goals: (i) to define the state of wet and dry deposition in regional models, (ii) to evaluate how dry deposition influences air concentration and flux predictions, and (iii) to identify the causes for prediction differences. The evaluation compares LULC-specific dry deposition and effective conductances and fluxes.
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Short summary
We integrate bioaccumulation and biotic Hg transformations into a coupled ecosystem–mercury model to assess their effect on marine Hg cycling. Bioaccumulation increases methylmercury levels, especially in productive coastal waters, and alters Hg exchange between the Baltic and North Seas. These results highlight strong ecosystem feedbacks on marine Hg dynamics.
We integrate bioaccumulation and biotic Hg transformations into a coupled ecosystem–mercury...
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