Enhanced insight into the biogeochemical cycle of Hg in the Antarctic marine environment of Terra Nova Bay via isotopic analysis
Vecchio, M.A.; Abou-Zeid, L.; Suàrez-Criado, L.; Vandermeiren, M.; Grotti, M.; Vanhaecke, F. (2025). Enhanced insight into the biogeochemical cycle of Hg in the Antarctic marine environment of Terra Nova Bay via isotopic analysis. Chemosphere 373: 144157. https://dx.doi.org/10.1016/j.chemosphere.2025.144157
In: Chemosphere. Elsevier: Oxford. ISSN 0045-6535; e-ISSN 1879-1298, more
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| Keywords |
Aquatic organisms > Marine organisms
Cycles > Chemical cycles > Geochemical cycle > Biogeochemical cycle
Mercury
Antarctica [Marine Regions]
Marine/Coastal |
| Author keywords |
Isotope ratio; Multi-collector ICP-MS |
| Authors | | Top |
- Vecchio, M.A.
- Abou-Zeid, L.
- Suàrez-Criado, L.
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- Vandermeiren, M.
- Grotti, M.
- Vanhaecke, F., more
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| Abstract |
Mercury (Hg) is a globally significant pollutant, which is particularly concerning due to its ability to undergo long-range atmospheric transport and its bioaccumulation and biomagnification in marine ecosystems, even in remote regions like Antarctica. This study explores the biogeochemical cycling of Hg in the marine coastal environment of Terra Nova Bay (Antarctica) by determining the total content of mercury (THg) and its isotopic composition in fish (Trematomus bernacchii), bivalve molluscs (Adamussium colbecki) and sediment samples, collected in 1996-1998 and 2021. Significantly lower THg concentrations are found in the organisms sampled in 2021 compared to those sampled in 1996–1998, with a concurrent shift toward higher δ202Hg (governed by mass-dependent isotope fractionation MDF) and lower Δ199Hg and Δ201Hg (governed by mass-independent isotope fractionation MIF) values. These results suggest changes in the exposure to Hg and the photochemical processes that the element and its species undergo, likely influenced by differences in the environmental conditions during the sampling periods, such as light exposure and ice cover. Sex-specific analysis of the 2021 fish samples further suggests differences in Hg accumulation and both MDF and MIF isotopic patterns between male and female specimens, emphasising a potential effect of sex on Hg exposure and dynamics. However, due to the limited number of individuals analyzed and the pooling of samples, this sex differentiation is still preliminary. Finally, the linear increase of Δ199Hg as a function of Δ201Hg during trophic transfer suggests MeHg bioaccumulation along the food chain. These findings provide valuable insights into the biogeochemical cycling of Hg in the Antarctic coastal marine environment and underscore the need for ongoing monitoring of Hg (including isotopic analysis) in this fragile ecosystem. |
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