The CLAW hypothesis: a review of the major developments

Greg P. Ayers; Jill M. Cainey

doi:10.1071/EN07080

RESEARCH FRONT

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The CLAW hypothesis: a review of the major developments

Greg P. Ayers ^A and Jill M. Cainey ^B ^C

+ Author Affiliations

- Author Affiliations

^A CSIRO Marine and Atmospheric Research, Aspendale, Vic. 3195, Australia.

^B Cape Grim Baseline Air Pollution Station, Bureau of Meteorology, Smithton, Tas. 7330, Australia.

^C Corresponding author. Email: j.cainey@bom.gov.au

Environmental Chemistry 4(6) 366-374 https://doi.org/10.1071/EN07080
Submitted: 29 October 2007 Accepted: 12 November 2007 Published: 6 December 2007

Environmental context. Understanding the role of clouds in the warming and the cooling of the planet and how that role alters in a warming world is one of the biggest uncertainties climate change researchers face. Important in this regard is the influence on cloud properties of cloud condensation nuclei, the tiny atmospheric particles necessary for the nucleation of every single cloud droplet. The anthropogenic contribution to cloud condensation nuclei is known to be large in some regions through knowledge of pollutant emissions; however, the natural processes that regulate cloud condensation nuclei over large parts of the globe are less well understood. The CLAW hypothesis provides a mechanism by which plankton may modify climate through the atmospheric sulfur cycle via the provision of sulfate cloud condensation nuclei. The CLAW hypothesis was published over 20 years ago and has stimulated a great deal of research.

Abstract. The CLAW hypothesis has for 20 years provided the intriguing prospect of oceanic and atmospheric systems exhibiting in an intimately coupled way a capacity to react to changing climate in a manner that opposes the change. A great number of quality scientific papers has resulted, many confirming details of specific links between oceanic phytoplankton and dimethylsulfide (DMS) emission to the atmosphere, the importance of DMS oxidation products in regulation of marine atmospheric cloud condensation nucleus (CCN) populations, and a concomitant influence on marine stratocumulus cloud properties. However, despite various links in the proposed phytoplankton–DMS–CCN–cloud albedo climate feedback loop being affirmed, there has been no overall scientific synthesis capable of adequately testing the hypothesis at a global scale. Moreover, significant gaps and contradictions remain, such as a lack of quantitative understanding of new particle formation processes in the marine atmospheric boundary layer, and of the extent to which dynamical, rather than microphysical, cloud feedbacks exist. Nevertheless, considerable progress has been made in understanding ‘Earth System Science’ involving the integration of ocean and atmospheric systems inherent in the CLAW hypothesis. We present here a short review of this progress since the publication of the CLAW hypothesis.

References

[1] R. Charlson , J. Lovelock , M. Andreae , S. Warren , Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate. Nature 1987 , 326, 655.
        | Crossref | GoogleScholarGoogle Scholar |

[2] Lovelock J. E., Gaia: A new look at life on Earth 1979 (Oxford University Press: Oxford, UK).

[3] J. E. Lovelock , L. Margulis , Atmospheric homeostatis for and by the biosphere: the Gaia Hypothesis. Tellus 1974 , 26, 2.


[4] S. Twomey , The influence of pollution on the shortwave albedo of clouds, J. Atmos. Sci. 1977 , 34, 1149.
        | Crossref | GoogleScholarGoogle Scholar |

[5] S. Twomey , Pollution and planetary albedo. Atmos. Environ. 1974 , 8, 1251.
        | Crossref | GoogleScholarGoogle Scholar |

[6] J. C. G. Walker , P. B. Hays , J. F. Kasting , A negative feedback mechanism for the long-term stabilization of Earth’s surface temperature. J. Geophys. Res. 1981 , 86, 9776.


[7] J. E. Lovelock , M. Whitfield , Life span of the biosphere. Nature 1982 , 296, 561.
        | Crossref | GoogleScholarGoogle Scholar |

[8] J. E. Lovelock , J. Maggs , R. A. Rasmussen , Atmospheric dimethylsulphide and the natural sulphur cycle. Nature 1972 , 237, 452.
        | Crossref | GoogleScholarGoogle Scholar |

[9] G. E. Shaw , Bio-controlled thermostasis involving the sulfur cycle. Clim. Change 1983 , 5, 297.
        | Crossref | GoogleScholarGoogle Scholar |

[10] S. M. Turner , G. Malin , P. S. Liss , D. S. Harbour , P. M. Holligan , The seasonal variation of dimethylsulfide and dimethylsulfoniopropionate concentrations in nearshore waters. Limnol. Oceanogr. 1988 , 33, 364.


[11] P. W. Boyd , S. C. Doney , Modelling regional responses by marine pelagic marine ecosystems to climate change. Geophys. Res. Lett. 2002 , 29, 1806.
        | Crossref | GoogleScholarGoogle Scholar |

[12] S. D. Archer , Few short-cuts to predicting biological control of DMS emissions. Environ. Chem. 2007 , 4, 404.
        | Crossref | GoogleScholarGoogle Scholar |

[13] G. V. Wolfe , M. S. Steinke , G. O. Kirst , Grazing-activated chemical defense in a unicellular marine alga. Nature 1997 , 387, 894.
        | Crossref | GoogleScholarGoogle Scholar |

[14] G. Malin , W. H. Wilson , G. Bratbak , P. S. Liss , N. H. Mann , Elevated production of dimethylsulfide resulting from viral infection of cultures of Phaeocystis pouchetii. Limnol. Oceanogr. 1998 , 43, 1389.


[15] B. C. Nguyen , S. Belviso , N. Mihalopoulos , J. Gostan , P. Nival , Dimethylsulfide production during natural phytoplanktonic blooms. Mar. Chem. 1988 , 24, 133.
        | Crossref | GoogleScholarGoogle Scholar |

[16] S. M. Turner , P. D. Nightingale , L. J. Spokes , M. I. Liddicoat , P. S. Liss , Increased dimethylsulphide concentrations in sea water from in situ iron enrichment. Nature 1996 , 383, 513.
        | Crossref | GoogleScholarGoogle Scholar |

[17] J. Stefels , Physiological aspects of the production and conversion of DMSP in marine algae and higher plants. J. Sea Res. 2000 , 43, 183.
        | Crossref | GoogleScholarGoogle Scholar |

[18] R. Simó , S. D. Archer , C. Pedros-Alio , L. Gilpin , C. E. Stelfox-Widdicombe , Coupled dynamics of dimethylsulfoniopropionate and dimethylsulfide cycling and the microbial food web in surface waters of the North Atlantic. Limnol. Oceanogr. 2002 , 47, 53.


[19] K. Caldeira , M. E. Wickett , Anthropogenic carbon and ocean pH. Nature 2003 , 425, 365.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[20] J. C. Orr , V. J. Fabry , O. Aumont , L. Bopp , S. C. Doney , R. A. Feely , A. Gnanadesikan , N. Gruber , et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 2005 , 437, 681.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[21] U. Riebesell , I. Zondervan , B. Rost , P. D. Tortell , R. E. Zeebe , F. M. Morel , Reduced calcification of marine plankton in response to increased atmospheric CO₂. Nature 2000 , 407, 364.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[22] O. W. Wingenter , K. B. Haase , M. Zeigler , D. R. Blake , F. S. Rowland , B. C. Sive , A. Paulino , R. Thyrhaug , et al. Unexpected consequences of increasing CO₂ and ocean acidity on marine production of DMS and CH₂ClI: potential climate impacts. Geophys. Res. Lett. 2007 , 34, L05710.
        | Crossref | GoogleScholarGoogle Scholar |

[23] M. Vogt , M. Steinke , S. Turner , A. Paulino , M. Meyerhofer , U. Riebesell , C. LeQuere , P. Liss , Dynamics of dimethylsulphoniopropionate and dimethylsulphide under different CO₂ concentrations during a mesocosm experiment. Biogeosciences Discuss. 2007 , 4, 3673.


[24] P. W. Boyd , T. Jickells , C. S. Law , S. Blain , E. A. Boyle , K. O. Buesseler , K. H. Coale , J. J. Cullen , et al. Mesoscale iron enrichment experiments 1993–2005: synthesis and future directions. Science 2007 , 315, 612.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[25] P. W. Boyd , A. J. Watson , C. S. Law , E. R. Abraham , T. Trull , R. Murdoch , D. C. E. Bakker , A. R. Bowie , et al. A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization. Nature 2000 , 407, 695.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[26] P. Liss , A. Chuck , D. Bakker , S. Turner , Ocean fertilization with iron: effects on climate and air quality. Tellus B 2005 , 57, 269.
        | Crossref | GoogleScholarGoogle Scholar |

[27] R. Cropp , J. Norbury , Plankton modelling and CLAW. Environ. Chem. 2007 , 4, 388.
        | Crossref | GoogleScholarGoogle Scholar |

[28] Liss P. S., Merlivat L., Air–sea gas exchange rates: introduction and synthesis, in The Role of Air–Sea Exchange in Geochemical Cycling (Ed. P. Buat-Menard) 1986, p. 113 (Reidel: Dordrecht, the Netherlands).

[29] R. Wanninkhof , Relationship between wind speed and gas exchange over the ocean. J. Geophys. Res. 1992 , 97, 7373.


[30] P. D. Nightingale , G. Malin , C. S. Law , A. J. Watson , P. S. Liss , M. I. Liddicoat , J. Boutin , R. C. Upstill-Goddard , In situ evaluation of air–sea gas exchange parameterizations using novel conservative and volatile tracers. Global Biogeochem. Cy. 2000 , 14, 373.
        | Crossref | GoogleScholarGoogle Scholar |

[31] D. T. Ho , C. S. Law , M. J. Smith , P. Schlosser , M. Harvey , P. Hill , Measurements of air–sea gas exchange at high wind speeds in the Southern Ocean: implications for global parameterizations. Geophys. Res. Lett. 2006 , 33, L16611.
        | Crossref | GoogleScholarGoogle Scholar |

[32] G. P. Ayers , R. W. Gillett , J. P. Ivey , B. Schafer , A. Gabric , Short-term variability in marine atmospheric dimethylsulfide concentration. Geophys. Res. Lett. 1995 , 22, 2513.
        | Crossref | GoogleScholarGoogle Scholar |

[33] B. W. Blomquist , C. W. Fairall , B. J. Huebert , D. J. Kieber , G. R. Westby , DMS sea–air transfer velocity: direct measurements by eddy covariance and parameterization based on the NOAA/COARE gas transfer model. Geophys. Res. Lett. 2006 , 33, L07601.
        | Crossref | GoogleScholarGoogle Scholar |

[34] C. A. Marandino , W. J. De Bruyn , S. D. Miller , E. S. Saltzman , Eddy correlation measurements of the air/sea flux of dimethylsulfide over the North Pacific Ocean. J. Geophys. Res. 2007 , 112, D03301.
        | Crossref | GoogleScholarGoogle Scholar |

[35] Whelpdale D. M., Kaiser M. S. (Eds), Global acid deposition assessment, in Environmental Pollution Monitoring and Research Programme Report Series, Vol. 106. WMO/TD No. 777 1996, pp. 107–134 (World Meteorological Organization: Geneva).

[36] M. O. Andreae , C. D. Jones , P. M. Cox , Strong present-day aerosol cooling implies a hot future. Nature 2005 , 435, 1187.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[37] J. E. Kristjansson , T. Iversen , A. Kirkevag , Ø. Seland , J. Debernard , Response of the climate system to aerosol direct and indirect forcing: role of cloud feedbacks. J. Geophys. Res. 2005 , 110, D24206.
        | Crossref | GoogleScholarGoogle Scholar |

[38] Forster P., Ramaswamy V., Artaxo P., Berntsen T., Betts R., Fahey D. W., Haywood J., Lean J., et al., Changes in atmospheric constituents and in radiative forcing, in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Eds S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, H. L. Miller) 2007, Ch. 2, p. 129 (Cambridge University Press: Cambridge, UK and New York, USA).

[39] G. P. Ayers , J. P. Ivey , R. W. Gillett , Coherence between seasonal cycles of dimethylsulfide, methanesulphonate and sulphate in marine air. Nature 1991 , 349, 404.
        | Crossref | GoogleScholarGoogle Scholar |

[40] Gillett R. W., Ayers G. P., Ivey J. P., Gras J. L., Measurement of dimethylsulfide, sulfur dioxide, methanesulfonic acid and non-sea salt sulfate at the Cape Grim Baseline Station, in Dimethylsulfide: Oceans, Atmosphere and Climate (Eds G. Restelli, G. Angeletti) 1993, p. 171 (Kluwer Academic Press: Dordrecht, Netherlands).

[41] G. P. Ayers , J. M. Cainey , R. W. Gillett , J. P. Ivey , Atmospheric sulphur and cloud condensation nuclei in marine air in the southern hemisphere. Phil. Trans. R. Soc. London B 1997 , 352, 203.
        | Crossref | GoogleScholarGoogle Scholar |

[42] E. S. Saltzman , S. A. Yvon , P. A. Matrai , Low-level atmospheric sulfur dioxide measurement using HPLC/fluorescence detection. J. Atmos. Chem. 1993 , 17, 73.
        | Crossref | GoogleScholarGoogle Scholar |

[43] G. P. Ayers , J. M. Cainey , H. Granek , C. Leck , Dimethylsulfide oxidation and the ratio of methanesulfonate to non-sea-salt sulfate in marine aerosol. J. Atmos. Chem. 1996 , 25, 307.
        | Crossref | GoogleScholarGoogle Scholar |

[44] F. Yin , D. Grosjean , J. H. Seinfeld , Photooxidation of dimethylsulfide and dimethyldisulfide. I: mechanism development. J. Atmos. Chem. 1990 , 11, 309.
        | Crossref | GoogleScholarGoogle Scholar |

[45] F. Yin , D. Grosjean , J. H. Seinfeld , Photooxidation of dimethylsulfide and dimethyldisulfide. II: mechanism evaluation. J. Atmos. Chem. 1990 , 11, 365.
        | Crossref | GoogleScholarGoogle Scholar |

[46] G. P. Ayers , R. W. Gillett , J. M. Cainey , A. L. Dick , Chloride and bromide loss from sea-salt particles in Southern Ocean air. J. Atmos. Chem. 1999 , 33, 299.
        | Crossref | GoogleScholarGoogle Scholar |

[47] R. von Glasow , P. Crutzen , Model study of multiphase DMS oxidation with a focus on halogens. Atmos Chem. Phys. 2004 , 4, 589.


[48] T. S. Bates , B. J. Huebert , J. L. Gras , F. B. Griffiths , P. A. Durkee , International Global Atmospheric Chemistry (IGAC) project’s First Aerosol Characterization Experiment (ACE-1): overview. J. Geophys. Res. 1998 , 103, 16297.
        | Crossref | GoogleScholarGoogle Scholar |

[49] M. A. J. Curran , G. B. Jones , H. Burton , Spatial distribution of dimethylsulfide and dimethylsulfoniopropionate in the Australasian sector of the Southern Ocean. J. Geophys. Res. 1998 , 103, 16677.
        | Crossref | GoogleScholarGoogle Scholar |

[50] W. J. De Bryun , T. S. Bates , J. M. Cainey , E. S. Saltzman , Shipboard measurements of dimethylsulfide and SO₂ south-west of Tasmania during the First Aerosol Characterization Experiment (ACE-1). J. Geophys. Res. 1998 , 103, 16703.
        | Crossref | GoogleScholarGoogle Scholar |

[51] S. Twomey , T. A. Wojciechowski , Observation of the geographical variation of cloud condensation nuclei. J. Atmos. Sci. 1969 , 26, 648.
        | Crossref | GoogleScholarGoogle Scholar |

[52] J. M. Cainey , M. J. Harvey , Dimethylsulfide, a limited contributor to new particle formation in the clean marine boundary layer. Geophys. Res. Lett. 2002 , 29, 1128.
        | Crossref | GoogleScholarGoogle Scholar |

[53] H. Sievering , J. Boatman , E. Gorman , Y. Kim , L. Anderson , G. Ennis , M. Luria , S. Pandis , Removal of sulphur from the marine boundary layer by ozone oxidation in sea-salt aerosols. Nature 1992 , 360, 571.
        | Crossref | GoogleScholarGoogle Scholar |

[54] H. Berresheim , M. O. Andreae , G. P. Ayers , R. W. Gillett , J. T. Merrill , V. J. Harris , W. L. Chameides , Airborne measurements of dimethylsulfide, sulfur dioxide and aerosol ions over the Southern Ocean south of Australia. J. Atmos. Chem. 1990 , 10, 341.
        | Crossref | GoogleScholarGoogle Scholar |

[55] W. De Bruyn , D. Wylie , E. Saltzman , M. Harvey , J. Cainey , Dimethylsulfide and sulfur dioxide measurements at Baring Head, New Zealand. J. Atmos. Chem. 2002 , 41, 189.
        | Crossref | GoogleScholarGoogle Scholar |

[56] H. Berresheim , J. W. Huey , R. P. Thorn , Measurements of dimethylsulfide, dimethylsulfoxide, dimethylsulfone and aerosol ions at Palmer Station, Antarctica. J. Geophys. Res. 1998 , 103, 1629.
        | Crossref | GoogleScholarGoogle Scholar |

[57] A. D. Clarke , Z. Li , M. Litchy , Aerosol dynamics in the equatorial Pacific marine boundary layer: microphysics, diurnal cycles and entrainment. Geophys. Res. Lett. 1996 , 23, 733.
        | Crossref | GoogleScholarGoogle Scholar |

[58] T. S. Bates , J. A. Calhoun , P. K. Quinn , Variations in the methanesulfonate to sulfate molar ratio in submicrometre marine aerosol particles over the Pacific Ocean. J. Geophys. Res. 1992 , 97, 9859.


[59] A. Broadbent , G. B. Jones , Seasonal and diurnal cycles of dimethylsulphide, dimethylsulphoniopropionate and dimethylsulphoxide at One Tree Reef lagoon. Environ. Chem. 2006 , 3, 260.
        | Crossref | GoogleScholarGoogle Scholar |

[60] B. J. Huebert , D. J. Wylie , L. Zhuang , J. A. Heath , Production and loss of methanesulfonate and non-sea salt sulfate in the equatorial Pacific marine boundary layer. Geophys. Res. Lett. 1996 , 23, 737.
        | Crossref | GoogleScholarGoogle Scholar |

[61] C. Leck , C. Persson , Seasonal and short-term variability in dimethylsulfide, sulfur dioxide and biogenic sulfur and sea salt aerosol particles in the arctic marine boundary layer, during summer and autumn. Tellus B 1996 , 48, 272.
        | Crossref | GoogleScholarGoogle Scholar |

[62] B. C. Nguyen , N. Mihalopoulos , S. Belviso , Seasonal variation of atmospheric dimethylsulfide at Amsterdam Island in the southern Indian Ocean. J. Atmos. Chem. 1990 , 11, 123.
        | Crossref | GoogleScholarGoogle Scholar |

[63] J. P. Putaud , N. Mihalopoulos , B. C. Nguyen , J. M. Campin , S. Belviso , Seasonal variations of atmospheric sulfur dioxide and dimethylsulfide concentrations at Amsterdam Island in the southern Indian Ocean. J. Atmos. Chem. 1992 , 15, 117.
        | Crossref | GoogleScholarGoogle Scholar |

[64] J. Sciare , E. Baboukas , N. Mihalopoulos , Short-term variability of atmospheric DMS and its oxidation products at Amsterdam Island during summer time. J. Atmos. Chem. 2001 , 39, 281.
        | Crossref | GoogleScholarGoogle Scholar |

[65] J. Sciare , M. Kanakidou , N. Mihalopoulos , Diurnal and seasonal variation of atmospheric dimethylsulfoxide at Amsterdam Island in the southern Indian Ocean. J. Geophys. Res. 2000 , 105, 17257.
        | Crossref | GoogleScholarGoogle Scholar |

[66] B. Davison , C. Hewitt , Natural sulphur species from the North Atlantic and their contribution to the United Kingdom sulfur budget. J. Geophys. Res. 1992 , 97, 2475.


[67] B. Davison , C. N. Hewitt , C. D. O’Dowd , J. A. Lowe , M. H. Smith , M. Schwikowski , U. Baltensperger , R. M. Harrison , Dimethylsulfide, methanesulfonic acid and physiochemical aerosol properties in Atlantic air from the United Kingdom to Halley Bay. J. Geophys. Res. 1996 , 101, 22855.
        | Crossref | GoogleScholarGoogle Scholar |

[68] G. Kouvarakis , N. Mihalopoulos , Seasonal variation of dimethylsulfide in the gas phase and of methanesulfonate and non-sea-salt sulfate in the aerosol phase in the Eastern Mediterranean atmosphere. Atmos. Environ. 2002 , 36, 929.
        | Crossref | GoogleScholarGoogle Scholar |

[69] G. P. Ayers , J. L. Gras , Seasonal relationship between cloud condensation nuclei and aerosol methanesulphonate in marine air. Nature 1991 , 353, 834.
        | Crossref | GoogleScholarGoogle Scholar |

[70] J. L. Gras , Baseline atmospheric condensation nuclei at Cape Grim 1977–1987. J. Atmos. Chem. 1990 , 11, 89.
        | Crossref | GoogleScholarGoogle Scholar |

[71] R. Boers , G. P. Ayers , J. L. Gras , Coherence between seasonal variation in satellite-derived cloud optical depth and boundary layer CCN concentrations at a mid-latitude southern hemisphere station. Tellus B 1994 , 46, 123.
        | Crossref | GoogleScholarGoogle Scholar |

[72] R. Boers , J. B. Jensen , P. B. Krummel , Microphysical and short-wave radiative structure of stratocumulus clouds over the Southern Ocean: summer results and seasonal differences. Q. J. R. Meteorol. Soc. 1998 , 124, 151.
        | Crossref | GoogleScholarGoogle Scholar |

[73] F. Raes , Entrainment of free tropospheric aerosols as a regulating mechanism for cloud condensation nuclei in the remote marine boundary layer. J. Geophys. Res. 1995 , 100, 2893.
        | Crossref | GoogleScholarGoogle Scholar |

[74] T. S. Bates , V. N. Kapustin , P. K. Quinn , D. S. Covert , D. J. Coffman , C. Mari , P. A. Durkee , W. J. de Bruyn , et al. Processes controlling the distribution of aerosol particles in the lower marine boundary layer during the First Aerosol Characterization Experiment (ACE-1). J. Geophys. Res. 1998 , 103, 16369.
        | Crossref | GoogleScholarGoogle Scholar |

[75] Jimi S., Gras J. L., Siems S. T., Nanoparticles at Cape Grim: a regional view using Southern Ocean Atmospheric Photochemistry Experiment (SOAPEX-2) as a case study, in Baseline Atmospheric Program (Australia) 1999–2000 2003, p. 54 (Bureau of Meteorology and CSIRO Atmospheric Research: Melbourne).

[76] C. Mari , K. Suhre , R. Rosset , T. S. Bates , B. J. Huebert , A. R. Bandy , D. C. Thornton , S. Businger , One-dimensional modeling of sulfur species during the First Aerosol Characterization Experiment (ACE-1) Lagrangian B. J. Geophys. Res. 1999 , 104, 21733.
        | Crossref | GoogleScholarGoogle Scholar |

[77] G. E. Shaw , R. L. Benner , W. Cantrell , A. D. Clarke , On the regulation of climate: a sulphate particle feedback loop involving deep convection. Clim. Change 1998 , 39, 23.
        | Crossref | GoogleScholarGoogle Scholar |

[78] P. Kishcha , B. Starobinets , P. Alpert , Latitudinal variations of cloud and aerosol optical thickness trends based on MODros. Inf. Serv. satellite data. Geophys. Res. Lett. 2007 , 34, L05810.
        | Crossref | GoogleScholarGoogle Scholar |

[79] Hobbs P. V. (Ed.), Aerosol–cloud interactions, in Aerosol–Cloud–Climate Interactions 1993, p. 33 (Academic Press: San Diego, CA).

[80] R. T. Pinker , B. Zhang , E. G. Dutton , Do satellites detect trends in surface solar radiation? Science 2005 , 308, 850.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[81] J. E. Lovelock , A geophysiologist’s thoughts on the natural sulphur cycle. Philos. Trans. R. Soc. London B 1997 , 352, 143.
        | Crossref | GoogleScholarGoogle Scholar |

[82] J. E. Lovelock , L. R. Kump , Failure of climate regulation in a geophysiological model. Nature 1994 , 369, 732.
        | Crossref | GoogleScholarGoogle Scholar |

[83] A. J. Gabric , N. Murray , L. Stone , M. Kohl , Modelling the production of dimethylsulfide during a phytoplankton bloom. J. Geophys. Res. 1993 , 98, 22805.


[84] A. J. Gabric , P. Whetton , R. Cropp , Dimethylsulphide production in the subantarctic Southern Ocean under enhanced greenhouse conditions. Tellus B 2001 , 53, 273.
        | Crossref | GoogleScholarGoogle Scholar |

[85] A. J. Gabric , R. Simó , R. A. Cropp , J. Dachs , T. Hirst , Global estimates of the oceanic emission of dimethylsulfide under enhanced greenhouse conditions. Global Biogeochem. Cy. 2004 , 18, GB2014.
        | Crossref | GoogleScholarGoogle Scholar |

[86] A. J. Gabric , P. Whetton , R. Boers , G. P. Ayers , The impact of GCM predicted climate change on the air-to-sea flux of dimethylsulphide in the subantarctic Southern Ocean. Tellus B 1998 , 50, 388.
        | Crossref | GoogleScholarGoogle Scholar |

[87] L. Bopp , O. Aumont , S. Belviso , P. Monfray , Potential impact of climate change on marine dimethylsulfide emissions. Tellus B 2003 , 55, 11.
        | Crossref | GoogleScholarGoogle Scholar |

[88] S. Kloster , K. D. Six , J. Feichter , E. Maier-Reimer , E. Roeckner , P. Wetzel , P. Stier , M. Esch , Response of dimethylsulfide (DMS) in the ocean and atmosphere to global warming. J. Geophys. Res. 2007 , 112, G03005.
        | Crossref | GoogleScholarGoogle Scholar |

[89] J. R. Gunson , S. A. Spall , T. R. Anderson , A. Jones , I. J. Totterdell , M. J. Woodage , Climate sensitivity to ocean dimethylsulphide emissions. Geophys. Res. Lett. 2006 , 33, L07701.
        | Crossref | GoogleScholarGoogle Scholar |

[90] M. A. J. Curran , T. D. van Ommen , V. I. Morgan , K. L. Phillips , A. S. Palmer , Ice core evidence for Antarctic sea ice decline since the 1950s. Science 2003 , 302, 1203.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[91] A. J. Gabric , J. M. Shephard , J. M. Knight , G. Jones , A. J. Trevena , Correlations between the satellite-derived seasonal cycles of phytoplankton biomass and aerosol optical depth in the Southern Ocean: evidence for the influence of sea ice. Global Biogeochem. Cy. 2005 , 19, GB4018.
        | Crossref | GoogleScholarGoogle Scholar |

[92] M. Legrand , Ice-core records of atmospheric sulphur. Philos. Trans. R. Soc. London B 1997 , 352, 241.
        | Crossref | GoogleScholarGoogle Scholar |

[93] J. L. Sarmiento , R. Slater , R. Barber , L. Bopp , S. C. Doney , A. C. Hirst , J. Kieypas , R. Matear , et al. Response of ocean ecosystems to climate warming. Global Biogeochem. Cy. 2004 , 18, GB3003.
        | Crossref | GoogleScholarGoogle Scholar |

[94] W. W. Gregg , M. E. Conkright , Decadal changes in global ocean chlorophyll. Geophys. Res. Lett. 2002 , 29, 1730.
        | Crossref | GoogleScholarGoogle Scholar |

[95] M. J. Behrenfeld , E. Boss , D. A. Siegel , D. M. Shea , Carbon-based ocean productivity and phytoplankton physiology from space. Global Biogeochem. Cy. 2005 , 19, GB1006.
        | Crossref | GoogleScholarGoogle Scholar |

[96] A. J. Gabric , R. Cropp , G. P. Ayers , G. McTainsh , R. Braddock , Coupling between cycles of phytoplankton biomass and aerosol optical depth as derived from SeaWiFS time series in the Subantarctic Southern Ocean. Geophys. Res. Lett. 2002 , 29, 1112.
        | Crossref | GoogleScholarGoogle Scholar |

[97] S. M. Vallina , R. Simó , S. Gassó , What controls CCN seasonality in the Southern Ocean? A statistical analysis based on satellite-derived chlorophyll and CCN and model-estimated OH radical and rainfall. Global Biogeochem. Cy. 2006 , 20, GB1014.
        | Crossref | GoogleScholarGoogle Scholar |

[98] S. M. Vallina , R. Simó , Strong relationship between DMS and the solar radiation dose over the global surface ocean. Science 2007 , 315, 506.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[99] M. J. Harvey , The iron CLAW. Environ. Chem. 2007 , 4, 396.
        | Crossref | GoogleScholarGoogle Scholar |

[100] C. D. O’Dowd , M. Geever , M. K. Hill , M. H. Smith , S. G. Jennings , New particle formation: nucleation rates and spatial scales in the clean marine coastal environment. Geophys. Res. Lett. 1998 , 25, 1661.
        | Crossref | GoogleScholarGoogle Scholar |

[101] N. Meskhidze , A. Nenes , Phytoplankton and cloudiness in the Southern Ocean. Science 2006 ,
        | Crossref | GoogleScholarGoogle Scholar | PubMed |

[102] R. J. Weber , P. H. McMurry , L. Mauldin , D. J. Tanner , F. L. Eisele , F. J. Brechtel , S. M. Kreidenweis , G. L. Kok , et al. A study of new particle formation and growth involving biogenic and trace gases during the First Aerosol Characterization Experiment (ACE-1). J. Geophys. Res. 1998 , 103, 16385.
        | Crossref | GoogleScholarGoogle Scholar |

[103] P. S. Liss , J. E. Lovelock , Climate change, the effect of DMS emissions. Environ. Chem. 2007 , 4, 377.
        | Crossref | GoogleScholarGoogle Scholar |

[104] O. W. Wingenter , Isoprene, cloud droplets and phytoplankton. Science 2007 , 317, 42.
        | Crossref | GoogleScholarGoogle Scholar |

[105] C. D. O’Dowd , M. H. Smith , Physico-chemical properties of aerosols over the North-east Atlantic: evidence for wind-speed-related submicron sea-salt aerosol production. J. Geophys. Res. 1993 , 98, 1137.


[106] Y. J. Yoon , P. Brimblecombe , Modelling the contribution of sea salt and dimethylsulfide-derived aerosol to marine CCN. Atmos. Chem. Phys. Discuss. 2001 , 1, 93.


[107] C. D. O’Dowd , J. A. Lowe , M. H. Smith , Coupling sea-salt and sulphate interactions and its impact on cloud droplet concentration predictions. Geophys. Res. Lett. 1999 , 26, 1311.
        | Crossref | GoogleScholarGoogle Scholar |

[108] M. Smith , Sea-salt particles and the CLAW Hypothesis. Environ. Chem. 2007 , 4, 391.
        | Crossref | GoogleScholarGoogle Scholar |

[109] A. D. Clarke , S. R. Owens , J. Zhou , An ultrafine sea-salt flux from breaking waves: implications for CCN in the remote marine atmosphere. J. Geophys. Res. 2006 , 111, D06202.
        | Crossref | GoogleScholarGoogle Scholar |

[110] E. D. Nilsson , E. M. Martensson , J. S. van Ekeren , G. de Leeuw , M. Moerman , C. D. O’Dowd , Primary marine aerosol emissions: size-resolved eddy covariance measurements with estimates of the sea salt and organic carbon fractions. Atmos. Chem. Phys. Discuss. 2007 , 7, 13345.


[111] E. M. Martensson , E. D. Nilsson , G. de Leeuw , L. H. Cohen , H.-C. Hansson , Laboratory simulations and parameterizations of the primary marine aerosol productions. J. Geophys. Res. 2003 , 108, 4297.
        | Crossref | GoogleScholarGoogle Scholar |

[112] C. Leck , E. K. Bigg , Biogenic particles in the surface microlayer and overlaying atmosphere in the central Arctic Ocean during summer. Tellus B 2005 , 57, 305.
        | Crossref | GoogleScholarGoogle Scholar |

[113] C. Leck , E. K. Bigg , Source and evolution of marine aerosol – a new perspective. Geophys. Res. Lett. 2005 , 32, L19803.
        | Crossref | GoogleScholarGoogle Scholar |

[114] E. K. Bigg , Sources, nature and influence on climate of marine airborne particles. Environ. Chem. 2007 , 4, 155.
        | Crossref | GoogleScholarGoogle Scholar |

[115] C. Leck , E. K. Bigg , Comparison of sources and nature of the tropical aerosol with summer high Arctic aerosol. Tellus B 2007 ,
        | Crossref | GoogleScholarGoogle Scholar |

[116] H. Sievering , J. Cainey , M. Harvey , J. McGregor , S. Nichol , P. Quinn , Non-sea salt sulfate (NSS) budget in the remote marine boundary layer under clear sky and normal cloudiness conditions: evidence for enhanced NSS production by O₃ oxidation in seasalt aerosols. J. Geophys. Res. 2004 , 109, D19317.
        | Crossref | GoogleScholarGoogle Scholar |

[117] W. C. Keene , H. Maring , J. R. Maben , D. J. Kieber , A. A. P. Pszenny , E. E. Dahl , M. A. Izaguirre , A. J. Davis , et al. Chemical and physical characteristics of nascent aerosols produced by bursting bubbles at a model air–sea interface. J. Geophys. Res. 2007 , 112, D21202.
        | Crossref | GoogleScholarGoogle Scholar |

[118] Intergovernmental Panel on Climate Change, Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Eds S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, H. L. Miller) 2007 (Cambridge University Press: Cambridge, UK and New York, USA).

[119] M. O. Andreae , Ocean-atmosphere interactions in the global biogeochemical sulfur cycle. Mar. Chem. 1990 , 30, 1.
        | Crossref | GoogleScholarGoogle Scholar |