Biogeochemical Dynamics of Molybdenum in a Crater Lake: Seasonal Impact and Long-Term Removal

Alassane Thiam (1, 2) , Didier Jézéquel (3) , Alexis Groleau (3) , François Prévot (4) , Filipa Lopes (5) , Patrick Albéric (6) , Catherine Quiblier (6, 7) , Elivira Bura-Nakic (8) , Irena Ciglenečki (8) , Hassiba Lazar (9) , Eric Viollier (9)

1 LPS - Laboratoire de Physique Statistique de l'ENS
2 YSM - Yale School of Medicine [New Haven, Connecticut]
3 IPGP - Institut de Physique du Globe de Paris
4 IHAP - Interactions hôtes-agents pathogènes [Toulouse]
5 LGPM - Laboratoire de Génie des Procédés et Matériaux - EA 4038
6 MNHN - Muséum national d'Histoire naturelle
7 UPD7 - Université Paris Diderot - Paris 7
8 MSF Genève
9 Kenta Biotech Ltd

Despite a large variety of processes that can control Mo and its potential to become an environmental tracer of euxinic environment, this element is not often studied in lakes. The aim of this paper is to identify main seasonal biogeochemical processes that involve Mo in a well constrained freshwater system (Lake Pavin water-column) in order to evaluate their respective importance. In Lake Pavin, 4 main processes have been identified: 1) the transitional process represented by Mo assimilation of by phytoplankton in the epilimnion (nitrogen biological fixation and nitrate assimilation); 2) transient process represented by dissolved Mo adsorption onto Fe and Mn metal oxides at oxic/anoxic interface (depth 50 - 60 m); 3) Mo precipitation where apparent sulfide production rate is maximum, and from 80 m depths; 4) release of dissolved Mo due to Mo benthic flux or input from a deep source.

Mots clés: Molybdenum; Biogeochemical Cycles; Diatoms; ICP-MS; Meromictic Lake

Domaines: Chimie

Alassane Thiam, Didier Jézéquel, Alexis Groleau, François Prévot, Filipa Lopes, et al.. Biogeochemical Dynamics of Molybdenum in a Crater Lake: Seasonal Impact and Long-Term Removal. Journal of Water Resource and Protection, 2014, 06 (04), pp.256 - 271. ⟨10.4236/jwarp.2014.64031⟩. ⟨hal-01237946⟩