Streams are natural integrators of landscape, subsurface, and in-stream biogeochemical processes at the catchment- to basin-scale. This subtheme utilizes stream water chemistry in relation to hydrologic response to investigate the importance of energy inputs, water transit times, bedrock mineralogy, landscape age, vegetation, and carbon cycling on critical zone development (e.g. mineral weathering rates).
Image: Jemez River. Photo: Jessica Driscoll
Groundwater transit times are greatest in streams draining north-facing hillslopes with lower solar radiation, thicker soils and deeper flowpaths. These longer transit times may enhance mineral weathering rates and increase dissolved solute loads to surface waters. In addition, north-facing catchments may have greater net ecosystem production due to increased water availability. Cooler and wetter soils should reduce heterotrophic soil respiration, increasing both soil carbon pools and dissolved organic matter export relative to south facing catchments.
The master transit time distribution of variable flow systems. Heidbüchel I., Troch P.A., Lyon S.W., and Weiler M. (2012): Water Resources Research 48(6): W06520
Determining Controls on Variable Response Times from Nested Sub-catchments. I. Heidbuechel, Troch, P.A. (2011): AGU Fall Meeting Presentations Abstract H43N-05.
Tracking Varying Mean Transit Time in a Semi-Arid Catchment . Heidbuechel, I., Troch, P.A., Lyon, S.W. (2010): AGU Fall Meeting (Poster) Abstract H11C-0813.