Endres, Sonja , Hepach, Helmke , Marandino, Christa, Quack, Birgit and Engel, Anja (2015) Microbial control of bromocarbons in the surface ocean. [Poster] In: ASLO Aquatic Sciences Meeting 2015. , 22.-27.02.2015, Granada, Spain .

Abstract

Oceanic bromocarbons are highly reactive volatile organic compounds and may contribute up to 40% of stratospheric ozone depletion in mid latitudes. High sea-air fluxes of bromocarbons in the tropical regions have been related to biological cycling in the surface ocean, mainly by phytoplankton and bacteria, but the underlying processes and magnitude of the biogenic sources and sinks are poorly known. In order to understand temporal and spatial fluctuations of oceanic bromocarbon emissions, we studied microbial production and removal processes in the surface ocean during a research cruise with RV ‘Sonne’ (OASIS-Sonne) to the tropical Indian Ocean and combined them with observational data of bromocarbon concentrations in the water and atmosphere. Water samples were incubated with 13C-labelled bromoform substrate in gas tight bottles to determine bromocarbon consumption rates. Oxygen production and consumption were monitored to estimate the auto- or heterotrophic process rates in the water body. Additional controls were sterile-filtered to differentiate between biological and chemical processes. Attained rates will be compared to measured depth profiles of bromocarbon concentrations, bacteria and phytoplankton biomass as well as organic matter concentrations.

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