Marine sources of bromoform in the global open ocean - global patterns and emissions.

Stemmler, I., Hense, I. and Quack, Birgit (2015) Marine sources of bromoform in the global open ocean - global patterns and emissions. Open Access Biogeosciences (BG), 12 (6). pp. 1967-1981. DOI 10.5194/bg-12-1967-2015.

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Abstract

Bromoform (CHBr3) is one important precursor 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 phytoplankton that contains the enzyme bromoperoxidase. Coastal sources of bromoform are higher than open ocean sources. However, open ocean emissions are important because the transfer of tracers into higher altitude in the air, i.e. into the ozone layer, strongly depends on the location of emissions. For example, emissions in the tropics are more rapidly transported into the upper atmosphere than emissions from higher latitudes. Global spatio-temporal features of bromoform emissions are poorly constrained. Here, a global three-dimensional ocean biogeochemistry model (MPIOM-HAMOCC) is used to simulate bromoform cycling in the ocean and emissions into the atmosphere using recently published data of global atmospheric concentrations (Ziska et al., 2013) as upper boundary conditions. Our simulated surface concentrations of CHBr3 match the observations well. Simulated global annual emissions based on monthly mean model output are lower than previous estimates, including the estimate by Ziska et al. (2013), because the gas exchange reverses when less bromoform is produced in non-blooming seasons. This is the case for higher latitudes, i.e. the polar regions and northern North Atlantic. Further model experiments show that future model studies may need to distinguish different bromoform-producing phytoplankton species and reveal that the transport of CHBr3 from the coast considerably alters open ocean bromoform concentrations, in particular in the northern sub-polar and polar regions.

Document Type: Article
Additional Information: WOS:000352112900024
Keywords: HALOGENATED ORGANIC-COMPOUNDS; ATLANTIC-OCEAN; SOUTHERN-OCEAN; BIOGENIC BROMINE; METHYL-IODIDE; MODEL; CHEMISTRY; BROMOCARBONS; HALOCARBONS; MACROALGAE
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.5194/bg-12-1967-2015
ISSN: 1726-4170
Projects: SOPRAN, Future Ocean
Date Deposited: 04 Dec 2014 13:34
Last Modified: 28 Nov 2017 17:42
URI: http://oceanrep.geomar.de/id/eprint/26224

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