HR: 0800h
AN: B41B-0200    [Abstracts]
TI: CARBOLAKE: European Natural Lakes as a Source of Carbon to the Atmosphere
AU: * Kastowski, M
EM: kastow@uni-leipzig.de
AF: University Leipzig, Institute of Geophysics and Geology, Talstr. 35, Leipzig, 04103 Germany
AU: Vecsei, A
EM: vecsei@uni-leipzig.de
AF: University Leipzig, Institute of Geophysics and Geology, Talstr. 35, Leipzig, 04103 Germany
AU: Hinderer, M
EM: hinderer@geo.tu-darmstadt.de
AF: Technical University Darmstadt, Institute of Applied Geosciences, Schnittspahnstr. 9, Darmstadt, 64287 Germany
AB: Many lakes are oversaturated in CO₂ with respect to the atmosphere. In contrast lake sediments contain high amounts of carbon that is withdrawn from the atmosphere for a presumable long time. The aim of the CARBOLAKE project is to quantify the role of lakes and reservoirs within the global carbon cycle, in a first step on the European scale. Carbon dioxide concentrations in the surface water of lakes were calculated from pH, dissolved inorganic carbon or acid neutralizing capacity. Available measurements of fluxes or concentrations were added from the literature. Potential fluxes were calculated for an average wind speed of 3 m s^-1. Data from 3637 water samples (3030 lakes and reservoirs) were checked for potential CO₂ emission. Values range from -37 to 2191 mmol m^-2 d^-1 with a mean of 104 mmol m^-2 d^-1 or about 450 g C m^-2 a^-1. 85% of the samples were oversaturated with respect to the atmosphere. Long term carbon burial was evaluated from published studies. Carbon sedimentation data are now available for 144 lakes with Carbon accumulation rates up to 55 g m^-2 a^-1. The mean rate was only about 3 g m^-2 a^-1. European lakes are dominated by boreal lakes without significant carbonate precipitation. Organic carbon sedimentation usually does not exceed 10 g C m^-2 a^-1. Until now the sedimentation dataset is not representative and does not include reservoirs which have assumed very high carbon accumulation rates. In conclusion most naturally lakes act as carbon sources. The annual carbon emission of naturally lakes largely exceeds the storage in the sediment. The estimated net loss is about 70*10¹² g per year, similar to the estimated emission from European estuaries. During the ongoing investigation the dataset will be extended, particularly for reservoir sedimentation. Further analyses including environmental influences will give a better understanding of the control factors leading to a complete carbon budget of European lakes and reservoirs.
DE: 0428 Carbon cycling (4806)
DE: 0458 Limnology (1845, 4239, 4942)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
SC: Biogeosciences [B]
MN: Fall Meeting 2005