Benthic bioturbation: A canary in the mine for the retention and release of metals from estuarine sediments

After the largest mining tailings spill in Brazil, the Rio Doce estuarine ecosystem was severely impacted by metal contamination. In a 28-day laboratory experiment, we examined the effects of the polychaeta Laeonereis sp. on fluxes of oxygen and metal across the sediment-water interface. The density...

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Bibliographic Details
Published in:Marine pollution bulletin 2021-11, Vol.172, p.112912-112912, Article 112912
Main Authors: Barcellos, Diego, Jensen, Sebastian S.K., Bernardino, Angelo F., Gabriel, Fabrício A., Ferreira, Tiago O., Quintana, Cintia O.
Format: Article
Language:English
Subjects:
Aluminum
Benthic fauna
Benthos
Bioturbation
Brackishwater environment
Cadmium
Chromium
Contaminants
Contamination
Copper
Density
Estuaries
Estuarine sediments
Fluxes
Heavy metals
Iron
iron oxides
Laeonereis
Manganese
Metals
Mine tailings
Mine wastes
Nickel
Oxidation
Oxygen
Redox
Sediment
Sediment-water interface
Sediments
Solid phases
Uptake
Zinc
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Summary:After the largest mining tailings spill in Brazil, the Rio Doce estuarine ecosystem was severely impacted by metal contamination. In a 28-day laboratory experiment, we examined the effects of the polychaeta Laeonereis sp. on fluxes of oxygen and metal across the sediment-water interface. The density-dependent effect of Laeonereis sp. in the oxygen and metal fluxes was tested at low and high (74 and 222 ind m−2, respectively) densities, and compared with defaunated controls. The higher worm density had an amplified effect on the oxygen flux, sediment uptake of Al and Mn, and Fe oxidation compared with the control, but no significant effects on other metals (Ba, Cd, Co, Cr, Cu, Ni, and Zn). Higher worm density increased the oxidation of Fe phases, but no effect in the solid phase of other metals. Consequently, Laeonereis sp. bioturbation prevents the reduction of Fe phases and the release of metal-bound-contaminants to estuarine systems. [Display omitted] •Density-dependent effect of Laeonereis sp. in the O2 and metal fluxes•Benthic bioturbation increased the influx of Al and Mn (retained by the sediment).•Higher Laeonereis sp. density promoted oxidation of Fe mineral phases.•Bioturbation influenced the effluxes of Cr, Ni, Cd, and Ba.•Loss of benthic fauna in Fe-rich sediments may intensify chronic effects of contamination.
ISSN:0025-326X
1879-3363
DOI:10.1016/j.marpolbul.2021.112912