Abstract
Brownification, increased water color and DOC in surface waters, is a large-scale environmental problem, probably caused by climate change. We will analyze the magnitude, time course, cause(s) and ecosystem effects of brownification in S Sweden through combined limnological, paleolimnological and plant/soil ecological approaches. Recent (last decades) and past (last 1000 years) changes in water color/DOC will be compared with climatic data and landscape characteristics. Lake monitoring data will be used, complemented with analyses of pollen, pigments and sediment organic matter. We will select 50 lakes in a humic gradient, which will be sampled for water and sediment chemistry and biota. Samples from the lakes will be used for construction of a transfer function for humic matter/DOC, as well as to give insights into changes in plankton communities over the DOC gradient. Sediment cores from three lakes will be sampled for high resolution long-term (1000 yr) records of lake and catchment characteristics, based on IR spectroscopy, pigments, C and N elemental and isotopic composition, and pollen. Experiments and modeling will be made on leaching of DOC from soils under various scenarios of precipitation and vegetation. The project will test effects of lake brownification on plankton, periphyton and macrophyte communities through field enclosure experiments. Lake DOC concentrations will be modeled under various scenarios of runoff, DOC-losses from soils and in-lake DOC processing.
Sweden