Potential impact of climate change on marine dimethyl sulfide emissions

Dimethyl sulfide (DMS) is a biogenic compound produced in sea-surface water and outgased to the atmosphere. Once in the atmosphere, DMS is a significant source of cloud condensation nuclei in the unpolluted marine atmosphere. It has been postulated that climate may be partly modulated by variations in DMS production through a DMS-cloud condensation nuclei-albedo feedback. We present here a modelled estimation of the response of DMS sea-water concentrations and DMS fluxes to climate change, following previous work on marine DMS modeling (Aumont et al., 2002) and on the global warming impact on marine biology (Bopp et al., 2001). An atmosphere—ocean general circulation model (GCM) was coupled to a marine biogeochemical scheme and used without flux correction to simulate climate response to increased greenhouse gases (a 1% increase per year in atmospheric CO2 until it has doubled). The predicted global distribution of DMS at 1 × CO2 compares reasonably well with observations; however, in the high latitudes, very elevated concentrations of DMS due to spring and summer blooms of Phaeocystis can not be reproduced. At 2 × CO2, the model estimates a small increase of global DMS flux to the atmosphere (+2%) but with large spatial heterogeneities (from −15% to +30% for the zonal mean). Mechanisms affecting DMS fluxes are changes in (1) marine biological productivity, (2) relative abundance of phytoplankton species and (3) wind intensity. The mean DMS flux perturbation we simulate represents a small negative feedback on global warming; however, the large regional changes may significantly impact regional temperature and precipitation patterns.

[1]  O. Aumont,et al.  Dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) sea surface distributions simulated from a global three-dimensional ocean carbon cycle model , 2002 .

[2]  Raphael Kudela,et al.  A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean , 1996, Nature.

[3]  E. Maier‐Reimer,et al.  Geochemical cycles in an Ocean General Circulation Model , 1993 .

[4]  T. Bates,et al.  Regional and seasonal variations in the flux of oceanic dimethylsulfide to the atmosphere , 1987 .

[5]  P. Liss,et al.  The distribution of dimethyl sulphide and dimethylsulphoniopropionate in Antarctic waters and sea ice , 1995 .

[6]  R. Morrow,et al.  An Atlantic meridional transect of surface water dimethyl sulfide concentrations with 10–15 km horizontal resolution and close examination of ocean circulation , 2000 .

[7]  L. Stone,et al.  Modelling the production of dimethylsulfide during a phytoplankton bloom , 1993 .

[8]  Nikos Mihalopoulos,et al.  Summertime Seawater Concentrations of Dimethylsulfide in the Western Indian Ocean: Reconciliation of Fluxes and Spatial Variability with Long-Term Atmospheric Observations , 1999 .

[9]  David M. Glover,et al.  A new coupled, one-dimensional biological-physical model for the upper ocean: Applications to the JGOFS Bermuda Atlantic Time-series Study (BATS) site , 1996 .

[10]  R. Wanninkhof.  Relationship between wind speed and gas exchange over the ocean , 1992 .

[11]  G. Ayers,et al.  Dimethylsulfide in marine air at Cape Grim, 41°S , 1995 .

[12]  T. Bates,et al.  Physico‐chemical modeling of the First Aerosol Characterization Experiment (ACE 1) Lagrangian B: 2. DMS emission, transport and oxidation at the mesoscale , 1998 .

[13]  Hervé Claustre,et al.  The trophic status of various oceanic provinces as revealed by phytoplankton pigment signatures , 1994 .

[14]  S. Warren,et al.  Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate , 1987, Nature.

[15]  Gurvan Madec,et al.  A global ocean mesh to overcome the North Pole singularity , 1996 .

[16]  P. Liss,et al.  Dimethyl sulphide and Phaeocystis: A review , 1994 .

[17]  A. Gabric,et al.  Dimethylsulphide production in the subantarctic southern ocean under enhanced greenhouse conditions , 2001 .

[18]  F. Dentener,et al.  Interannual variability of atmospheric dimethylsulfide in the southern Indian Ocean , 2000 .

[19]  D. Erickson.  A stability dependent theory for air‐sea gas exchange , 1993 .

[20]  Gurvan Madec,et al.  Potential impact of climate change on marine export production , 2001 .

[21]  M. Andreae,et al.  Biogenic sulfur emissions and aerosols over the tropical South , 1994 .

[22]  M. D. Keller,et al.  Physiological Aspects of the Production of Dimeyhtlsulfoniopropionate (DMSP) by Marine Phytoplankton , 1996 .

[23]  P. Whetton,et al.  The impact of simulated climate change on the air-sea flux of dimethylsulphide in the subantarctic Southern Ocean , 1998 .

[24]  Andrew S. Jones,et al.  Indirect sulphate aerosol forcing in a climate model with an interactive sulphur cycle , 2001 .

[25]  S. Ghan,et al.  Global ocean‐to‐atmosphere dimethyl sulfide flux , 1990 .

[26]  P. Buat-Ménard.  The role of air-sea exchange in geochemical cycling , 1986 .

[27]  Olivier Thual,et al.  Simulations couplées globales des changements climatiques associés à une augmentation de la teneur atmosphérique en CO2 , 1998 .

[28]  A. Kettle,et al.  Flux of dimethylsulfide from the oceans: A comparison of updated data sets and flux models , 2000 .

[29]  S. Watanabe,et al.  Dimethyl sulfide widely varying in surface water of the eastern North Pacific , 1995 .

[30]  Giacomo R. DiTullio,et al.  A global database of sea surface dimethylsulfide (DMS) measurements and a procedure to predict sea surface DMS as a function of latitude, longitude, and month , 1999 .