Acid/base character of dissolved organic carbon in soil and surface waters

This thesis deals with acid-base properties of dissolved organic carbon (DOC), which markedly affect chemistry of surface and soil water in mountain catchments. It describes long-term trends of acid-base character of organic acids (humic and fulvic acids) in two acid-impacted peaty catchments Tajga and Černý potok in Slavkov Forest, western Czech Republic between 1993 - 2010. Area was significantly acidified by sulfur emission from coal-burning power plants in the region which burned coal with a high content of sulfur (1 - 15 %). These power plants were desulphurized between 1994 - 1999 and observed changes are significantly affected by decrease of strong mineral acids atmospheric deposition. Changes during the period 2006 - 2010 were also studied in soil waters from Načetín in Ore Mountains. There are three forest stands - spruce, beech and limed spruce stand. Limed spruce stand was limed in August 2007. For an evaluation of similarity of acid/base character of DOC samples from Sweden, Portorico and Congo were also taken. Many studies examined DOC acid/base character using different analytical methods. These methods produced different and hardly comparable results. In this work rightness, reproducibility and errors of one of these methods - titration after transfering acids to H+ cycle - was tested. Method..