Processes controlling spatial and temporal dynamics of spring water chemistry in the Black Forest National Park

Markus Merk; Nadine Goeppert; Nico Goldscheider

doi:10.1016/j.scitotenv.2020.137742

Processes controlling spatial and temporal dynamics of spring water chemistry in the Black Forest National Park

Sci Total Environ. 2020 Jun 25:723:137742. doi: 10.1016/j.scitotenv.2020.137742. Epub 2020 Mar 10.

Authors

Markus Merk¹, Nadine Goeppert², Nico Goldscheider³

Affiliations

¹ Institute of Applied Geosciences, Division of Hydrogeology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany. Electronic address: markus.merk@kit.edu.
² Institute of Applied Geosciences, Division of Hydrogeology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany. Electronic address: nadine.goeppert@kit.edu.
³ Institute of Applied Geosciences, Division of Hydrogeology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany. Electronic address: nico.goldscheider@kit.edu.

PMID: 32222496
DOI: 10.1016/j.scitotenv.2020.137742

Abstract

Spring water chemistry is influenced by many factors, including geology, climate, vegetation and land use, which determine groundwater residence times and water-rock interaction. Changes in water chemistry can have a profound impact on their associated ecosystems. To protect these ecosystems and to evaluate possible changes, knowledge of the underlying processes and dynamics is important. We collected water samples at 20 locations during 5 campaigns within the water catchment area of the upper Schönmünz river in the Black Forest National Park, Southwest Germany and analyzed them hydro-chemically for their contents of inorganic constituents, organic carbon content, fluorescence properties as well as several physico chemical field parameters and spring discharge. Results show that water chemistry is strongly dependent on geology and that the response of dissolved organic carbon to changes in hydraulic conditions is highly dynamic. Due to increased flow through the upper soil layer during and after rain events, more organic carbon is extracted from the soil and transported with the water. Fluorescence EEM measurements indicate an allochthonous source of this organic carbon. This study can be used as baseline to assess future changes and serve as a supplement to ongoing studies of the spring ecosystems.

Keywords: Baseline study; Fractured sandstone aquifer; Near surface hillslope processes; Organic carbon; Water sampling.