Ledesma, Jose
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Abstract
In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeochemical processes occurring in the riparian zone (RZ). However, RZs are spatially heterogeneous and information about solute chemistry is typically limited. This is problematic when making inferences about stream chemistry. Hypothetically, the strength of links between riparian and stream chemistry is time-scale dependent. Using a ten-year (2003-2012) dataset from a northern Swedish catchment, we evaluated the suitability of RZ data to infer stream dynamics at different time scales. We focus on the role of the RZ versus upslope soils in controlling sulfate (SO42-) and dissolved organic carbon (DOC). A priori, declines in acid deposition and redox-mediated SO42- pulses control sulfur (S) fluxes and pool dynamics, which in turn affect dissolved organic carbon (DOC). We found that the catchment is currently a net source of S, presumably due to release of the S pool accumulated during the acidification period. In both, RZ and stream, SO42- concentrations are declining over time, whereas DOC is increasing. No temporal trends in SO42- and DOC were observed in upslope mineral soils. SO42- explained the variation of DOC in stream and RZ, but not in upslope mineral soil. Moreover, as SO42- decreased with time, temporal variability of DOC increased. These observations indicate that: (1) SO42- is still an important driver of DOC trends in boreal catchments and (2) RZ processes control stream SO42- and subsequently DOC independently of upslope soils. These phenomena are likely occurring in many regions recovering from acidification. Because water flows through a heterogeneous mosaic of RZs before entering the stream, upscaling information from limited RZ data to the catchment level is problematic at short-time scales. However, for long-term trends and annual dynamics, the same data can provide reasonable representations of riparian processes and support meaningful inferences about stream chemistry. (C) 2016 The Authors. Published by Elsevier B.V.
Keywords
Heterogeneity; Acidification; Upscaling; Catchment science; Biogeochemistry; DOC
Published in
Science of the Total Environment
2016, volume: 560-561, pages: 110-122
Publisher: ELSEVIER SCIENCE BV
SLU Authors
Futter, Martyn
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Laudon, Hjalmar
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Evans, Christopher
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
- Centre for Ecology and Hydrology (CEH)
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Köhler, Stephan
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Associated SLU-program
SLU Future Forests
Global goals (SDG)
SDG6 Clean water and sanitation
UKÄ Subject classification
Oceanography, Hydrology, Water Resources
Geosciences, Multidisciplinary
Environmental Sciences
Publication identifier
- DOI: https://doi.org/10.1016/j.scitotenv.2016.03.230
Permanent link to this page (URI)
https://res.slu.se/id/publ/77027