The subproject is dedicated to two main objectives: (i) to generate a revised global estimate of coastal halocarbon emissions accounting for those from seagrass meadows and (ii) to provide comprehensive isotopic data sets for the coastal and oceanic sinks and sources of selected halocarbons (CH₃Cl, CH₃Br, CH₃I and CHBr₃) using different upscaling and model approaches. In particular the formation and degradation of the monohalomethanes with large fractionation factors are assigned. The δ¹³C values of these compounds vary sensitively between sources and sinks making them a valuable tool to assess the current state and future changes in the marine and atmospheric environment.

Fig.1: Sampling of volatile halocarbon emissions in a seagrass meadow by a dynamic flux chamber.

Fig.2: Purge & tarp measurements of dissolved halocarbons on board FS METEOR

PI: R. Seifert

Contact: Richard Seifert (richard.seifert@zmaw.de)