Subproject: Investigations of the organic matter mineralization kinetics

 

Bernd Schneider, Hildegard Kubsch

The investigations of the kinetics of organic matter mineralization are based on measurements of the CO₂ accumulation in the Gotland Sea deep water. The vertical profiles of total CO₂ (C_T) are determined at time intervals of about two to three months. The C_T fraction generated by mineralization (^minC_T) is estimated by subtracting the C_T background which is defined by the C_T of the water during its last contact with the atmosphere and which may be obtained from estimates of the corresponding alkalinity and CO₂ partial pressure. Taking into account vertical mixing, the temporal increase of the ^minC_T is used to calculate mineralization rates for different depth levels. Relating the mineralization rates to the availability of organic matter and to the O₂ (SO₄^2-) concentrations will give rate constants for the decomposition of organic matter at different redox conditions.