EGU22-8253
https://doi.org/10.5194/egusphere-egu22-8253
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mercury released from newly formed volcano influence concentrations in the surrounding ocean 

Isabel Garcia Arevalo1, Joël Knoery1, Bastien Thomas1, Natalia Torres Rodriguez2, Lars-Eric Heimbürger Boavida2, Cecile Cathalot3, Emmanuel Rinnert3, and the Geoflamme shipboard scientific party*
Isabel Garcia Arevalo et al.
  • 1IFREMER, Contamination Chimique des Ecosystèmes Marins (CCEM), Nantes, France
  • 2Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France
  • 3IFREMER, Laboratoire Cycles Géochimiques et ressources (REM/GM/LCG), Plouzané, France
  • *A full list of authors appears at the end of the abstract

Volcanic and geothermal areas are important natural sources of mercury, with mercury concentrations in volcanic gases above the atmospheric background. Individual volcanoes exhibit variable degassing features and behavior, leading to considerable uncertainty in global geogenic mercury fluxes estimations. Likewise, studies on mercury emissions from submarine volcanic and hydrothermal sites are scarce. Nevertheless, information on those natural inputs is needed to better estimate the anthropogenic mercury enrichment, and thus for the implementation of the Minamata convention.

During Spring 2021, the GEOFLAMME campaign took place at the northern end of the Mozambique channel, where we examined the influence of volcanic inputs from a volcano that had formed less than 2 years ago near Mayotte Island.  Water samples were obtained with a trace metal-clean CTD rosette and all-titanium high-pressure samplers using the remotely operated vehicle Victor 6000 on board R/V Pourquoi pas?. Total mercury was measured on board via Cold Vapour Atomic Fluorescence Spectroscopy (CV-AFS) following the EPA method 1631. Exhaled fluid samples from titanium samplers followed the same analytical scheme, but at the shore laboratory.

Mercury levels measured from water column showed increased concentrations near the seafloor.  Total mercury measured in fluid samples from the different venting sites showed concentrations 3 to 60 times higher than surrounding seawater.

Our study provides new insight to the understanding for mercury biogeochemistry, the interactions between magmatism, tectonics and fluids circulation processes, as well as the implications on the physical-chemical properties of the water column. It also improves our knowledge on present-day mercury cycling in the marine environment usingfield-based data. Ongoing work will attempt to quantify seafloor mercury inputs to the vicinity of the Mayotte Island.

Geoflamme shipboard scientific party:

Olivier Rouxel Vivien Guyader Thomas Giunta Christophe Rabouille Jean Pierre Donval Bruno Bombled Yoan Germain Romain Davy Manon Mastin Jean Pascal Dumoulin

How to cite: Garcia Arevalo, I., Knoery, J., Thomas, B., Torres Rodriguez, N., Heimbürger Boavida, L.-E., Cathalot, C., and Rinnert, E. and the Geoflamme shipboard scientific party: Mercury released from newly formed volcano influence concentrations in the surrounding ocean , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8253, https://doi.org/10.5194/egusphere-egu22-8253, 2022.