FN Archimer Export Format
PT J
TI Diagenetic production, accumulation and sediment-water exchanges of methylmercury in contrasted sediment facies of Lake Titicaca (Bolivia)
BT 
AF Guédron, S.
   Audry, S.
   Acha, D.
   Bouchet, S.
   Point, D.
   Condom, T.
   Heredia, C.
   Campillo, S.
   Baya, A.
   Groleau, A.
   Amice, Erwan
   Amouroux, D.
AS 1:1,2;2:3;3:4;4:5;5:3;6:6;7:1,4;8:1;9:3;10:7;11:8;12:4,5;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:;
C1 Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France
   Laboratorio de Hidroquímica, Instituto de Investigaciones Químicas, Universidad Mayor de San Andres, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia
   Géosciences Environnement Toulouse, UMR5563, IRD UR 154, Université Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France
   Unidad de Calidad Ambiental (UCA), Instituto de Ecología, Universidad Mayor de San Andrés, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia
   Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les matériaux, Pau, France
   Univ. Grenoble Alpes, CNRS, IRD, Grenoble INP, Institut des Géosciences de l'Environnement (IGE), UMR 5001, F-38000 Grenoble, France
   Institut de Physique du Globe de Paris (IPGP), 1, rue Jussieu, 75238 Paris Cedex 05, France
   LEMAR- Laboratoire des sciences de l'environnement marin, Institut Universitaire Européen de la Mer - Technopôle Brest-Iroise, Rue Dumont d'Urville, 29280 Plouzané, France
C2 UNIV GRENOBLE ALPES, FRANCE
   UNIV MAYOR SAN ANDRES, BOLIVIA
   OBSERV MIDI PYRENEES, FRANCE
   UNIV MAYOR SAN ANDRES, BOLIVIA
   UNIV PAU & PAYS ADOUR, FRANCE
   UNIV GRENOBLE ALPES, FRANCE
   IPGP, FRANCE
   CNRS, FRANCE
UM LEMAR
IN WOS Cotutelle UMR
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
   copubli-sud
IF 7.963
TC 18
UR https://archimer.ifremer.fr/doc/00615/72735/71843.pdf
LA English
DT Article
DE ;Methylmercury;Lake sediment;Early diagenesis;High altitude ecosystem;Diffusive fluxes
AB Monomethylmercury (MMHg) concentrations in aquatic biota from Lake Titicaca are elevated although the mercury (Hg) contamination level of the lake is low. The contribution of sediments to the lake MMHg pool remained however unclear. In this work, seven cores representative of the contrasted sediments and aquatic ecotopes of Lake Titicaca were sliced and analyzed for Hg and redox-sensitive elements (Mn, Fe, N and S) speciation in pore-water (PW) and sediment to document early diagenetic processes responsible for MMHg production and accumulation in PW during organic matter (OM) oxidation. The highest MMHg concentrations (up to 12.2 ng L−1 and 90% of THg) were found in subsurface PWs of the carbonate-rich sediments which cover 75% of the small basin and 20% of the large one. In other sediment facies, the larger content of OM restricted MMHg production and accumulation in PW by sequestering Hg in the solid phase and potentially also by decreasing its bioavailability in the PW. Diagenetically reduced S and Fe played a dual role either favoring or restricting the availability of Hg for biomethylation. The calculation of theoretical diffusive fluxes suggests that Lake Titicaca bottom sediments are a net source of MMHg, accounting for more than one third of the daily MMHg accumulated in the water column of the Lago Menor. We suggest that in the context of rising anthropogenic pressure, the enhancement of eutrophication in high altitude Altiplano lakes may increase these MMHg effluxes into the water column and favor its accumulation in water and biota. 
PY 2020
PD JUL
SO Science Of The Total Environment
SN 0048-9697
PU Elsevier BV
VL 723
UT 000535897200019
DI 10.1016/j.scitotenv.2020.138088
ID 72735
ER

EF