Biogenic halocarbons and light alkyl nitrates measured on water bottle samples during POLARSTERN cruise ANT-XVIII/2 (EisenEx)@en

The ocean plays a significant role in the trace gas composition of the atmosphere, via sea-to-air emissions, which are controlled by biotic and abiotic production and consumption processes occurring within the water column. Both the halocarbons and alkyl nitrates affect the 'oxidising capacity' of the atmosphere, primarily as a result of their influence on ozone concentration. Halocarbons have been shown to be produced biogenically by various species of microalgae in laboratory studies. However, the production processes and their fluxes in the open ocean are poorly characterised. In general, the alkyl nitrates have a predominantly anthropogenic source, but atmospheric measurements in the remote troposphere have led to assumptions of an oceanic source of the light alkyl nitrates. The aims of this project were therefore to contribute to the knowledge of the occurrence, distribution and dynamics of biogenic halogenated gases in seawater, and to test the hypothesis that the ocean is a source of the light alkyl nitrates. […]