Changes in Soil Dissolved Organic Carbon Affect Reconstructed History and Projected Future Trends in Surface Water Acidification
Hruska, Jakub; Kram, Pavel; Moldan, Filip; Oulehle, Filip; Evans, Christopher D.; Wright, Richard F.; Kopacek, Jiri; Cosby, Bernard J.
Preindustrial (1850s) and future (2060) streamwater chemistry of an anthropogenically acidified small catchment was estimated using theMAGICmodel for three different scenarios for dissolved organic carbon (DOC) concentrations and sources. The highest modeled pH=5.7 for 1850s as well as for 2060 (pH= 4.4) was simulated given the assumption that streamwater DOC concentration was constant at the 1993 level. A scenario accounting for an increase of DOC as an inverse function of ionic strength (IS) of soilwater and streamwater resulted in much lower preindustrial (pH=4.9) and future recovery to (pH=4.1) if the stream riparian zone was assumed to be the only DOC source. If upland soilwater (where significant DOC increase was observed at -5 and -15 cm) was also included, DOC was partly neutralized within the soil and higher preindustrial pH=5.3 and future pH=4.2 were estimated. The observedDOC stream flux was 2-4 times higher than the potential carbon production of the riparian zone, implying that this is unlikely to be the sole DOC source. Modeling based on the assumption that stream DOC changes are solely attributable to changes in the riparian zone appears likely to underestimate preindustrial pH.
Acidification; Surface waters; Soils; Dissolved organic carbon; MAGIC model; Preindustrial water chemistry
Water, Air, and Soil Pollution
2014, Volume: 225, number: 7, article number: 2015
UKÄ Subject classification
Meteorology and Atmospheric Sciences
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