UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Spatial and temporal variations of base cation release from chemical weathering on a hillslope scale

Erlandsson, M; Oelkers, EH; Bishop, K; Sverdrup, H; Belyazid, S; Ledesma, JLJ; Köhler, SJ; (2016) Spatial and temporal variations of base cation release from chemical weathering on a hillslope scale. Chemical Geology , 441 pp. 1-13. 10.1016/j.chemgeo.2016.08.008. Green open access

[thumbnail of Oelkers_Weathering.ms.final_.pdf]
Preview
Text
Oelkers_Weathering.ms.final_.pdf - Accepted version

Download (887kB) | Preview

Abstract

Cation release rates to catchment runoff from chemical weathering were assessed using an integrated catchment model that included the soil's unsaturated, saturated and riparian zones. In-situ mineral dissolution rates were calculated in these zones as a function of pH, aluminum and dissolved organic carbon (DOC) concentrations along a hillslope in Northern Sweden where soil water was monitored over nine years. Three independent sets of mineral dissolution equations of varying complexity were used: PROFILE, Transition-State Theory (TST), and the Palandri & Kharaka database. Normalization of the rate-coefficients was necessary to compare the equations, as published rate-coefficients gave base cation release rates differing by several orders of magnitude. After normalizing the TST- and Palandri & Kharaka-rate coefficients to match the base cation release rates calculated from the PROFILE-equations, calculated Ca2 + and Mg2 + release rates are consistent with mass balance calculations, whereas those of Na+ and K+ are overestimated. Our calculations further indicate that a significant proportion of base cations are released from the organic soils in the near-stream zone, in part due to its finer texture. Of the three sets of rate equations, the base cation release rates calculated from the normalized TST-equations were more variable than those calculated using the other two sets of equations, both spatially and temporally, due to its higher sensitivity to pH. In contrast, the normalized Palandri & Kharaka-equations were more sensitive to variations in soil temperature.

Type: Article
Title: Spatial and temporal variations of base cation release from chemical weathering on a hillslope scale
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.chemgeo.2016.08.008
Publisher version: http://dx.doi.org/10.1016/j.chemgeo.2016.08.008
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Mineral dissolution kinetics; PROFILE; Transition-State-Theory; PHREEQC; Acidification; Riparian zone
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1508638
Downloads since deposit
0Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item