XVI International Botanical Congess

Carbonyl sulfide (COS) is influencing the Earth's radiation budget as well as heterogeneous reaction chemistry in the stratosphere leading to ozone destruction. Despite considerable efforts to improve our understanding of the global COA cycle, recent compilations of available data show large uncertainties in the magnitude of the various sources and sinks. Field measurements in an open oak woodland ecosystem at a rural site in northern California and laboratory experiments under controlled environmental conditions revealed that lichens possess the potential to take up COS in the same range as higher vegetation, which is commonly regarded as the major sink for atmospheric COS. Based on laboratory measurements an algorithm was developed to link the investigated dependence on thallus water content, the ambient COS concentration and on temperature. We compared the role of lichens with the different compartments of the ecosystem (i.e. soil and vegetation) with respect to their potential to act as sinks for COS.