CS26 Organic Carbon Dynamics
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
JuutinenS, University of Joensuu, Joensuu, Finland, sari.juutinen@joensuu.fi
Alm, J, , Finnish Forest Research Institute, Joensuu, Finland, jukka.alm@metla.fi
Larmola, T, , University of Joensuu, Joensuu, Finland, tuula.larmola@joensuu.fi
Huttunen, J, , University of Kuopio, Kuopio, Finland, jari.huttunen@uku.fi
Martikainen, P, , University of Kuopio, Kuopio, Finland, pertti.martikainen@uku.fi
Silvola, J, , University of Joensuu, Joensuu, Finland, jouko.silvola@joensuu.fi
 
Spatial Variability in Methane (CH4) Emissions from Boreal Lakes
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High emissions of methane (CH4) are detected from the lakes. Lakes are abundant in boreal landscapes and therefore significant sources of the atmospheric CH4 at regional scale. The aim of this study was to examine the relationships between lake productivity level, sediment and vegetation type and biomass of aquatic plants to determine whether these factors can be used to predict CH4 emissions. Methane emissions were measured from May to October in eastern Finland using closed static chamber method. Three lakes with productivity from mesotrophic to hypereutrofic, and having different size and hydrology were selected. Within a lake, the measurements were conducted in the different lacustrine zones, from forest margin to the pelagial zone. Sediment types varied from sandy and clay sediments to the mud sediments. Vegetation was the most important determinant for CH4 emission. The CH4 emissions were highest in the littoral zone among emergent sedge and reed vegetation. The variation in the littoral CH4 emissions was small between the lakes. The lake productivity level, however, determines the abundance of emergent vegetation and therefore the CH4 emissions from the lake.