ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-8-18409-2008 Air-sea fluxes of biogenic bromine from the tropical and North Atlantic Ocean Carpenter L. J. 1 Jones C. E. 1 Dunk R. M. 1 2 Hornsby K. E. 1 Department of Chemistry, University of York, York, YO10 5DD, UK now at: Crichton Carbon Centre, Crichton University Campus, Dumfries, DG1 4ZL, UK 21 10 2008 8 5 18409 18435 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/8/18409/2008/acpd-8-18409-2008.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/8/18409/2008/acpd-8-18409-2008.pdf

Air-sea fluxes and bulk seawater and atmospheric concentrations of bromoform (CHBr<sub>3</sub>) and dibromomethane (CH<sub>2</sub>Br<sub>2</sub>) were measured during two research cruises in the northeast Atlantic (53–59&deg; N, June–July 2006) and tropical eastern Atlantic Ocean including over the African coastal upwelling system (16–35&deg; N May–June 2007). Saturations and sea-air fluxes of these compounds generally decrease in the order coastal&gt;upwelling&gt;shelf&gt;open ocean, and a broad trend of elevated surface seawater concentrations with high chlorophyll<i>a</i> was observed. From limited data from eastern Atlantic coastlines, we tentatively suggest that globally, coastal and coastally-influenced waters together contribute ~2.4 Gmol Br yr<sup>&minus;1</sup> (24–56%) of CHBr<sub>3</sub>. We show that upwelling regions (coastal and equatorial) represent regional hot spots of bromocarbons, but are probably not of major significance globally, contributing only a few percent of the total global emissions of CHBr<sub>3</sub> and CH<sub>2</sub>Br<sub>2</sub>. We also show that the concentration ratio of CH<sub>2</sub>Br<sub>2</sub>/CHBr<sub>3</sub> in seawater is a strong function of concentration (and location), with a lower CH<sub>2</sub>Br<sub>2</sub>/CHBr<sub>3</sub> ratio found in coastal regions near to macroalgal sources.

 References Bilde, M., Wallington, T J., Ferronato, C., Orlando, J J., Tyndall, G S., Estupinan, E., and Haberkorn, S.: Atmospheric chemistry of CH<sub>2</sub>BrCl, CHBrCl<sub>2</sub>, CHBr<sub>2</sub>Cl, CF<sub>3</sub>CHBrCl, and CBr<sub>2</sub>Cl<sub>2</sub>, J. Phys. Chem. A, 102, 1976–1986, 1998. Butler, J H., King, D B., Lobert, J M., Montzka, S A., Yvon-Lewis, S A., Hall, B D., Warwick, N J., Mondeel, D J., Aydin, M., and Elkins, J W.: Oceanic distributions and emissions of short-lived halocarbons, Global Biogeochem. Cy., 21, GB1023, doi:10.1029/2006GB002732, 2007a. Butler, J H., Wallace, D., Carpenter, L., Hall, B., Montzka, S., Quack, B., Atlas, E., Smythe-Wright, D., and Yvon-Lewis, S.: A need for intercalibration of atmospheric and oceanic measurements of short-lived halocarbons, Poster presented at EGU, Vienna, 2007b. Carpenter, L J. and Liss, P S.: On temperate sources of bromoform and other reactive organic bromine gases, J. Geophys. Res., 105, 20 539–20 547, 2000. Carpenter, L J., Malin, G., Liss, P S., and Kupper, F C.: Novel biogenic iodine-containing trihalomethanes and other short-lived halocarbons in the coastal east Atlantic, Global Biogeochem. Cy., 14, 1191–1204, 2000. Carpenter, L J., Liss, P S., and Penkett, S A.: Marine organohalogens in the atmosphere over the Atlantic and Southern Oceans, J. Geophys. Res., 108(D9), 4256, doi:10.1029/2002JD002769, 2003. Carpenter, L J., Wevill, D J., Hopkins, J R., Dunk, R M., Jones, C E., Hornsby, K E., and McQuaid, J B.: Bromoform in tropical Atlantic air from 25 degrees N to 25 degrees S, Geophys. Res. Lett., 34, L11810, doi:10.1029/2007GL029893, 2007. Chuck, A L., Turner, S M., and Liss, P S.: Oceanic distributions and air-sea fluxes of biogenic halocarbons in the open ocean, J. Geophys. Res., 110, C10022, doi:10.1029/2004JC002741, 2005. Class, T H. and Ballschmiter, K.: Chemistry of organic traces in air .8. Sources and distribution of bromochloromethanes and bromochloromethanes in marine air and surface water of the Atlantic-Ocean, J. Atmos. Chem., 6, 35–46, 1988. Fedoseev, A.: Geostrophic circulation of surface waters on the shelf of north–west Africa, Rapp. P.-v. Réun. Cons. Int. Explor. Mer., 159, 32–37, 1970. Geen, C.: Selected marine sources and sinks of bromoform and other low molecular weight organobromines, M.Sc. Thesis, Dalhousie Univ., Halifax, Nova Scotia, Canada, 1992. Goodwin, K D., Schaefer, J K., and Oremland, R S.: Bacterial oxidation of dibromomethane and methyl bromide in natural waters and enrichment cultures, Appl. Environ. Microb., 64, 4629–4636, 1998. Hagen, E.: Northwest African upwelling scenario, Oceanol. Acta, 24, S113–S128, 2001. Kock, A., Gebhardt, S., and Bange, H W.: Methane emissions from the upwelling area off Mauritania (NW Africa), Biogeosciences, 5, 1119–1125, 2008. Kwok, W M., Zhao, C Y., Li, Y L., Guan, X G., and Phillips, D L.: Direct observation of an isopolyhalomethane O-H insertion reaction with water: Picosecond time-resolved resonance Raman study of the isobromoform reaction with water to produce a CHBr<sub>2</sub>OH product, J. Chem. Phys., 120, 3323–3332, 2004. Li, S M., Yokouchi, Y., Barrie, L A., Muthuramu, K., Shepson, P B., Bottenheim, J W., Sturges, W T., and Landsberger, S.: Organic and inorganic bromine compounds and their composition in the Arctic troposphere during polar sunrise, J. Geophys. Res., 99, 25 415–25 428, 1994. Mabey, W. and Mill, T.: Critical-review of hydrolysis of organic-compounds in water under environmental-conditions, J. Phys. Chem. Ref. Data, 7, 383–415, 1978. Menard, H W. and Smith, S M.: Hypsometry of ocean basin provinces, J. Geophys. Res., 71, 4305–4325, 1966. Minas, H J., Codispoti, L A., and Dugdale, R C.: Nutrients and primary production in the upwelling region off Northwest Africa, Rapp. P.-v. Réun. Cons. Int. Explor. Mer., 180, 148–180, 1982. Nielsen, J E. and Douglass, A R.: Simulation of bromoform's contribution to stratospheric bromine, J. Geophys. Res., 106, 8089–8100, 2001. Peterson, R G., Stramma, L., and Kortum, G.: Early concepts and chart of ocean circulation, Prog. Oceanogr. 37, 1–115, 1996. Pfeilsticker, K., Sturges, W T., Bosch, H., Camy-Peyret, C., Chipperfield, M P., Engel, A., Fitzenberger, R., Muller, M., Payan, S., and Sinnhuber, B M.: Lower stratospheric organic and inorganic bromine budget for the arctic winter 1998/99, Geophys. Res. Lett., 27, 3305–3308, 2000. Pradhan, Y., Lavender, S J., Hardman-Mountford, N J., and Aiken, J.: Seasonal and inter-annual variability of chlorophyll-a concentration in the Mauritanian upwelling: Observation of an anomalous event during 1998–1999, Deep-Sea Res. PT. II, 53, 1548–1559, 2006. Quack, B. and Wallace, D W R.: Air-sea flux of bromoform: Controls, rates, and implications, Global Biogeochem. Cy., 17, 1023, doi:10.1029/2002GB001890, 2003. Quack, B., Atlas, E., Petrick, G., Stroud, V., Schauffler, S., and Wallace, D W R.: Oceanic bromoform sources for the tropical atmosphere, Geophys. Res. Lett., 31, L23s05, doi:10.1029/2004GL020597, 2004. Quack, B., Atlas, E., Petrick, G., and Wallace, D W R.: Bromoform and dibromomethane above the Mauritanian upwelling: Atmospheric distributions and oceanic emissions, J. Geophys. Res., 112, D09312, doi:10.1029/2006jd007614, 2007. Riley, J P. and Chester, R.: Introduction to Marine Chemistry, Academic Press, St. Louis, Missouri, USA, p. 465, 1971. Ryther, J H.: Photosynthesis and fish production in the sea, Science, 166, 72–76, 1969. Salawitch, R J.: Atmospheric chemistry – biogenic bromine, Nature, 439, 275–277, doi:10.1038/439275a, 2006. Solomon, S., Garcia, R R., and Ravishankara, A R.: On the role of iodine in ozone depletion, J. Geophys. Res., 99, 20 491–20 499, 1994. Sturges, W T., Oram, D E., Carpenter, L J., Engel A., and Penkett, S A.: Bromoform as a source of bromine to the stratosphere, Geophys. Res. Lett., 27, 2081–2084, 2000. Tomczak, M.: The distribution of water masses at the surface as derived from T-S diagram analysis in the CINECA area, Rapp. P.-v. Réun. Cons. Int. Explor. Mer., 180, 48–49, 1980. von Glasow, R., von Kuhlmann, R., Lawrence, M. G., Platt, U., and Crutzen, P. J.: Impact of reactive bromine chemistry in the troposphere, Atmos. Chem. Phys., 4, 2481–2497, 2004. von~Glasow, R. and Crutzen, P J.: Tropospheric Halogen Chemistry, in: Treatise on Geochemistry Update 1, edited by: Holland, H D. and Turekian, K K., 4.02, 1–67, 2007. Wanninkhof, R.: Relationship between wind-speed and gas-exchange over the ocean, J. Geophys. Res., 97, 7373–7382, 1992. Wevill, D J., and Carpenter, L J.: Automated measurement and calibration of reactive volatile halogenated organic compounds in the atmosphere, Analyst, 129, 634–638, 2004. Wyatt, A R.: Shallow-water areas in space and time, J. Geolog. Soc., 144, 115–120, 1987. Yang, X., Cox, R A., Warwick, N J., Pyle, J A., Carver, G D., O'Connor, F M., and Savage, N H.: Tropospheric bromine chemistry and its impacts on ozone: A model study, J. Geophys. Res., 110, D23311, doi:10.1029/2005JD006244, 2005. Yokouchi, Y., Hasebe, F., Fujiwara, M., Takashima, H., Shiotani, M., Nishi, N., Kanaya, Y., Hashimoto, S., Fraser, P., Toom-Sauntry, D., Mukai, H., and Nojiri, Y.: Correlations and emission ratios among bromoform, dibromochloromethane, and dibromomethane in the atmosphere, J. Geophys. Res., 110, D23309, doi:10.1029/2005JD006303, 2005. Zhang, D Q., Zhong, J X., and Qiu, L X.: Kinetics of the reaction of hydroxyl radicals with CH<sub>2</sub>Br<sub>2</sub> and its implications in the atmosphere, J. Atmos. Chem., 27, 209–215, 1997 Zhou, Y., Mao, H., Russo, R S., Blake, D R., Wingenter, O W., Haase, K B., Ambrose, J., Varner, R K., Talbot, R., and Sive, B C.: Bromoform and dibromomethane measurements in the seacoast region of New Hampshire 2002–2004, J. Geophys. Res., 113, D08305, doi:10.1029/2007JD009103, 2008.