HR: 14:55h
AN: H33H-06 [Abstracts]
TI: Thio-arsenic species in alkaline, hypersaline, meromictic Mono Lake, California
AU: * Hollibaugh, J T
EM: aquadoc@uga.edu
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: Carini, S
EM: carini@uga.edu
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: Grleyk, H
EM: hakang@frontiergeosciences.com
AF: Frontier Geosciences, Inc., 414 Pontius Ave N, Seattle, WA 98109
United States
AU: Jellison, R
EM: jellison@lifesci.ucsb.edu
AF: SNARL, UCSB, SNARL, UCSB
Rt. 1 Box 198
1016 Mt. Morrison Road
, Mammoth Lakes, CA 93546
United States
AU: Joye, S B
EM: mjoye@uga.edu
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: LeCleir, G
EM: glecleir@uga.edu
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: Meile, C
EM: cmeile@uga.edu
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: Vasquez, L
EM: lydzies@yahoo.com
AF: Department of Marine Sciences, University of Georgia, Athens GA, GA 30602-3636
United States
AU: Wallschlger, D
EM: dwallsch@trentu.ca
AF: Environmental & Resource Studies Program, Trent University, Peterborough, ON K9J 7B8
Canada
AB:
Mono Lake had been meromictic for 8 years when sampled (Feb-Nov, 2002). Arsenic speciation was determined by IC-ASRS-ICP-MS
of samples preserved in the field by flash-freezing in liquid nitrogen. Arsenic speciation was dominated by arsenate when
oxygen was detectable, but shifted to dominance by reduced species once oxygen was no longer detectable. Thio-arsenic
species were the dominant form of As found in sulfidic waters. Maxima of thio-arsenic species with stoichiometries
consistent with mono-, di- and tri-thio-arsenic occurred in succession as sulfide concentration increased. A compound with
a stoichiometry consistent with tri-thio-arsenic was the dominant As species ($>$50% of total As) in high sulfide ($>$2 mM)
bottom water. Comparison of the data with a simple equilibrium model suggested that the distributions do not represent
simple chemical equilibria driven by sulfide concentration. Lower concentrations of total As in bottom water relative to
surface water suggest precipitation of As/S mineral phases in response to sulfide accumulation during prolonged anoxia.
UR: http://www.monolake.uga.edu
DE: 1845 Limnology
DE: 1030 Geochemical cycles (0330)
DE: 1045 Low-temperature geochemistry
DE: 1065 Trace elements (3670)
DE: 1615 Biogeochemical processes (4805)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting