Modeling solute transport and sulfate reduction in marsh sediments

Journal Article · Fri May 01 04:00:00 EDT 1987 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(87)90204-3· OSTI ID:6992555

Casey, W H; Lasage, A C

The seasonal oscillation in sulfate and chloride concentration profiles in some salt marsh sediments is due to exchange of solutes with water on the surface of the marsh, and to the desiccation of the sediment in summer. Desiccation is manifested by disappearance of surface waters, fluctuations in the location of the water table, and by removal of water from the sediment above the water table. The loss of water from the pore space is commonly accompanied by entry of air into the soil, which oxidizes sulfide. The oxidation causes titratable alkalinity to decrease and results in CO/sub 2/ degassing. Diffusion models of salinity can account for the observed profiles but only as long as the marsh in maintained inundated. The complexities introduced to the solute transport equations by sediment desiccation invalidate steady-state modeling of solute transport and diagenesis. The concentration profiles of dissolved products of sulfate reduction, such as bicarbonate, require months to reestablish a steady state after being disrupted. If the profiles of dissolved products of sulfate reduction are disrupted seasonally,such as by a season fluctuation in the water table, they may remain transient throughout the year.

• Research Organization: Pennsylvania State Univ., University Park (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6992555
• Journal Information: Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:5; ISSN GCACA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ACID NEUTRALIZING CAPACITY
AQUATIC ECOSYSTEMS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DEGASSING
DIAGENESIS
DIFFUSION
ECOSYSTEMS
GEOCHEMISTRY
GROUND WATER
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INTERSTITIAL WATER
MARSHES
MASS TRANSFER
MATHEMATICAL MODELS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
REDUCTION
SALINITY
SEASONAL VARIATIONS
SEDIMENTS
SOLUTES
STEADY-STATE CONDITIONS
SULFATES
SULFUR COMPOUNDS
VARIATIONS
WATER
WATER CHEMISTRY
WETLANDS