Biogeosciences, 12, 1967–1981, 2015 www.biogeosciences.net/12/1967/2015/ doi:10.5194/bg-12-1967-2015 © Author(s) 2015. CC Attribution 3.0 License. Marine sources of bromoform in the global open ocean – global patterns and emissions I. Stemmler1,3, I. Hense1, and B. Quack2 1Institute for Hydrobiology and Fisheries Science, University of Hamburg, CEN, Hamburg, Germany 2Geomar, Helmholtz Centre for Ocean Research, Kiel, Germany 3Max Planck Institute for Meteorology, Hamburg, Germany Correspondence to: I. Stemmler (
[email protected]) Received: 22 September 2014 – Published in Biogeosciences Discuss.: 7 November 2014 Revised: 27 February 2015 – Accepted: 2 March 2015 – Published: 25 March 2015 Abstract. Bromoform (CHBr3) is one important precursor 1 Introduction of atmospheric reactive bromine species that are involved in ozone depletion in the troposphere and stratosphere. In the open ocean bromoform production is linked to phyto- Bromoform (CHBr3) is one of the most abundant bromine- plankton that contains the enzyme bromoperoxidase. Coastal containing volatile halocarbons and is a considerable source sources of bromoform are higher than open ocean sources. of reactive bromine species in the atmosphere (e.g. Carpenter However, open ocean emissions are important because the and Liss, 2000; Law and Sturges, 2007; Salawitch, 2006). transfer of tracers into higher altitude in the air, i.e. into Due to its lifetime of approximately 3–4 weeks (Moortgat the ozone layer, strongly depends on the location of emis- et al., 1993; Law and Sturges, 2007), bromoform alters the sions. For example, emissions in the tropics are more rapidly bromine budget in both the troposphere and the stratosphere transported into the upper atmosphere than emissions from and can lead to ozone depletion with potential impacts on higher latitudes.