Factors Affecting the Leaching of Dissolved Organic Carbon after Tree Dieback in an Unmanaged European Mountain Forest

0494823 - BC 2019 RIV US eng J - Journal Article
Kopáček, Jiří - Evans, C. D. - Hejzlar, Josef - Kaňa, Jiří - Porcal, Petr - Šantrůčková, Hana
Factors Affecting the Leaching of Dissolved Organic Carbon after Tree Dieback in an Unmanaged European Mountain Forest.
Environmental Science and Technology. Roč. 52, č. 11 (2018), s. 6291-6299. ISSN 0013-936X. E-ISSN 1520-5851
R&D Projects: GA ČR GA17-15229S
Institutional support: RVO:60077344
Keywords : climate-change * biogeochemical processes * nitrogen deposition * soil-carbon * matter
OECD category: Water resources
Impact factor: 7.149, year: 2018

Forest disturbances affect ecosystem biogeochemistry, water quality, and carbon cycling. We analyzed water chemistry before, during, and after a dieback event at a headwater catchment in the Bohemian Forest (central Europe) together with an un-impacted reference catchment, focusing on drivers and responses of dissolved organic carbon (DOC) leaching. We analyzed data regarding carbon input to the forest floor via litter and throughfall, changes in soil moisture and composition, streamwater chemistry, discharge, and temperature. We observed three key points. (i) In the first 3 years following dieback, DOC production from dead biomass led to increased concentrations in soil, but DOC leaching did not increase due to chemical suppression of its solubility by elevated concentrations of protons and polyvalent cations and elevated microbial demand for DOC associated with high ammonium (NH4+) concentrations. (ii) DOC leaching remained low during the next 2 years because its availability in soils declined, which also left more NH(4)(+)available for nitrifiers, increasing NO(3)(-)and proton production that further increased the chemical suppression of DOC mobility. (iii) After 5 years, DOC leaching started to increase as concentrations of NO3-, protons, and polyvalent cations started to decrease in soil water. Our data suggest that disturbance-induced changes in N cycling strongly influence DOC leaching via both chemical and biological mechanisms and that the magnitude of DOC leaching may vary over periods following disturbance. Our study adds insights as to why the impacts of forest disturbances are sometime observed at the local soil scale but not simultaneously on the larger catchment scale.
Permanent Link: http://hdl.handle.net/11104/0288530