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RESEARCH PRODUCT

Biomethylation in the Southern Ocean and its contribution to the geochemical cycle of trace elements in Antarctica

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Publisher Summary This chapter focuses on biomethylation, which is a chemical process that leads to volatile alkylated compounds of elements, and is the only substantial alkylation process for some heavy metals in the environment. Volatile compounds dissolved in the ocean are transferred into the atmosphere. This is an important mechanism in the geochemical cycle of elements that contributes significantly to the global distribution of individual substances. Most of the methylated compounds are not very stable in the atmosphere because they can decompose. Antarctica and its surrounding polar ocean is one of the few areas on earth that is not directly influenced by anthropogenic sources and, hence natural biomethylation occurs. Alternative bioalkylations of halogens and other non-metals usually leads to permethylated or peralkylated products, which are relatively volatile and not very soluble in sea water. The transfer of volatile compounds from the ocean into the air is described by two-phase models for the substance flux “F” from the aqueous into the gaseous phase. Biomethylation takes place under polar conditions and contributes substantially to the concentration of VHOCs and heavy metals in the atmosphere.