Acknowledgments
This study was financially supported by the Academy of Finland,
Oulu University Scholarship Foundation and Maa- ja vesitekniikan tukiry.We wish to thank Seppo Kylli (Department of Chemistry, University
of Oulu) for the technical assistance and Reijo Seppänen (Finnish Forest
Research Institute) for the assistance in the field and carrying out the
sampling, and the laboratory staff of Metla (Vantaa) for performing
the DOC analyses of water samples.