TITLE:
Biogeochemical Dynamics of Molybdenum in a Crater Lake: Seasonal Impact and Long-Term Removal
AUTHORS:
Alassane Thiam, Didier Jézéquel, Alexis Groleau, François Prévot, Filipa Lopes, Patrick Albéric, Catherine Quiblier, Elivira Bura-Nakic, Irena Ciglenečki, Hassiba Lazar, Eric Viollier
KEYWORDS:
Molybdenum; Biogeochemical Cycles; Diatoms; ICP-MS; Meromictic Lake
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.4,
March
25,
2014
ABSTRACT: 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.