Granite weathering and the sensitivity of alpine lakes to acid deposition
Lake chemical data from the National Surface Water Survey (NSWS) were corrected for the effects of regional atmospheric deposition and then used to evaluate the role of weathering in supplying base cations, silica, sulfate, and alkalinity to surface waters in alpine vs. subalpine, and in glaciated vs. unglaciated granitic terrane of the western and southeastern US. Thermodynamic models, idealized reaction stoichiometry, and multivariate regression involving solutes and geographic variables indicate that irreversible weathering can largely account for lake chemistry. By contrast, relatively minor roles are played by reversible ion exchange in soils and sediments, terrestrial bioaccumulation, and transformation in lakes. The regional patterns in lake acidity components (NO{sub 3}, SO{sub 4}, DOC, CO{sub 2}), and statistical relationships between acidity and base cations demonstrate that rock weathering is limited by acid inputs in many alpine catchments prior to fall overturn. The empirical success of the Henriksen alkalinity model depends on a high Ca: Na weathering ration. The latter increase with increasing physical disturbance of the catchment (juvenility), hence under natural circumstances attains a maximum as a result of on-going or recent glaciation. The Henriksen model fails in geochemically old terrane, where cation losses accompanying silicate weathering attain steady state proportions.
- OSTI ID:
- 5945569
- Journal Information:
- Limnology and Oceanography; (United States), Vol. 35:5; ISSN 0024-3590
- Country of Publication:
- United States
- Language:
- English
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Executive summary - Assessing the response of Emerald Lake, an alpine watershed in Sequoia National Park, California, to acidification during snowmelt using a simple hydrochemical model
Assessing the response of Emerald Lake, an alpine watershed in Sequoia National Park, California, to acidification during snowmelt by using a simple hydrochemical model
Related Subjects
GRANITES
WEATHERING
LAKES
ACIDIFICATION
WATER CHEMISTRY
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOCONVERSION
BIOLOGICAL ACCUMULATION
DISSOLUTION
ION EXCHANGE
MATHEMATICAL MODELS
PH VALUE
SOIL CHEMISTRY
SOILS
THERMODYNAMIC MODEL
CHEMISTRY
IGNEOUS ROCKS
KINETICS
PARTICLE MODELS
PLUTONIC ROCKS
REACTION KINETICS
ROCKS
STATISTICAL MODELS
SURFACE WATERS
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)