Climate-driven enrichment of pollutants in peatlands
1Dept. Edafología y Química Agrícola, Universidad de Santiago de Compostela, Campus Universitario s/n, 15782 Santiago de Compostela, Spain
2Institute of Environmental Geochemistry, University of Heidelberg, INF 236 69120 Heidelberg, Germany
3Department of Geography and Environment, School of Geosciences, University of Aberdeen, Elphinstone Road, Aberdeen, AB24 3UF, UK
4Dept. of Ecology and Environmental Science, Umeå University, S901 87 Umeå, Sweden
Abstract. Peatlands play an important role for global carbon dynamics, acting as a sink or source depending on climate. Such changes imply a series of additional effects because peatlands are also an important reservoir of atmospherically derived pollutants. Using a multiproxy approach (non-pollen-palynomorphs, δ15N, C/N, Se, Br, I, Hg, Ti), we show a relationship between climate (wetter–drier) and peat decomposition, which affected element concentrations in a Spanish bog during the last 5500 years. Changes in superficial wetness played a critical role in the cycling of elements coupled to carbon dynamics. Dry phases caused increased peat mineralisation, resulting in a 2–3 times increase in concentrations of the analysed elements independent from atmospheric fluxes. Under the present trend of climate change large areas of northern peatlands are expected to be severely affected; in this context our findings indicate that the increase in carbon release, which leads to an enrichment of elements, may enhance the export of stored contaminants (Hg, organohalogens) to the aquatic systems or to the atmosphere.
Citation: Martínez Cortizas, A., Biester, H., Mighall, T., and Bindler, R.: Climate-driven enrichment of pollutants in peatlands, Biogeosciences, 4, 905-911, doi:10.5194/bg-4-905-2007, 2007.