WRDS Library [Home]
Digital Library Publications Videos Card Catalog

WWRC 84-04
Processes Controlling the Composition of Infiltrating Water in Forested Mountain Watersheds

Abstract

Chemical weathering in a high-elevation pine forest was studied by analysis of percolating soil solutions and associated solid phases. In the shallow soil (above 40 cm), soil-water chemistry is controlled by biological processes -- uptake by plants and decay in the litter layer. Below 40 cm mineral weathering becomes more important as a control, but solution compositions are so variable in space and time that it is impossible to define a simple weathering stoichiometry. Kaolinite is forming in the upper part of the soil profile and smectite in the lower part, although solution compositions indicate that kaolinite should be the more stable phase at all depths.

Dissolved organic carbon (DOC) values are high (average 38 mgC/l) in the forest floor litter, and decrease with depth in the mineral soil. In clay-rich, low-permeability soil the DOC loss and acquisition of cations take place close to the surface, whereas in more permeable soils DOC transport and chemical weathering extend to greater depths. There is some enhanced transport of Al and Fe as a result of complexing by organic acids. The mechanisms by which DOC is removed from solution are not clear.


Water Resources Publications List
Water Resources Data System Library | Water Resources Data System Homepage


  WRDS Library [Home]
Digital Library Publications Videos Card Catalog