Remote marine atmosphere

A more complex feedback has been proposed that involves the production of dimethylsulfide by certain classes of marine phytoplankton. Four observations in the remote marine atmosphere formed the basis of this idea ... 

Calhoun, J. A., T. S. Bates, and R. J. Charlson, Sulfur Isotope Measurements of Submicrometer Sulfate Aerosol Particles over the Pacific Ocean, Geophys. Res. Lett, 18, 1877-1880 (1991). Capaldo, K. P., and S. N. Pandis, Dimethylsulfide Chemistry in the Remote Marine Atmosphere Evaluation and Sensitivity Analysis of Available Mechanisms, J. Geophys. Res., 102, 23251-23267 (1997). 

The presence of non-seasalt sulfate particles in the remote marine atmosphere has important environmental consequences. As a result of their size and hydrophylicity, sulfate particles make good cloud condensation nuclei... 

The effects of anthropogenic sulfur dioxide on the remote marine atmosphere may be evident from rainwater studies by Chukhrov et al. (60) in which the isotopic composition of sulfur in rain was studied systematically at great distances from the continent. Rainwater sulfate ranged from +12.1 to +15.0 0/00 over the Atlantic and from +9.5 to +16.2 0/00 over the Pacific, with a one month average value of +13.3 0/00 for the two oceans. Their study included measurements of rainwater sulfate from a wide variety of continental areas and found that most inland 634S values were significantly lower than those over the oceans. The oceanic rainfall sulfate was most likely a mixture of the isotopically lower continental sulfate and the more enriched marine sulfate. 

Atlas E, Giam CS. 1981. Global transport of organic pollutants Ambient concentrations in the remote marine atmosphere. Science 211 163-165. 

In the early 1970s there was some concern that the sulfur cycle did not balance and that there needed to be additional global sources. When James Lovelock discovered DMS in the atmosphere of remote Ireland, this seemed a fine candidate to balance the sulfur cycle. The production of DMS in the oceans and its subsequent oxidation have been extensively investigated, particularly because of its role in producing sulfuric acid droplets that can act as an important cloud condensation nuclei in the remote marine atmosphere. 

Dimethylsulfoxide can readily be removed onto particles and there it can undergo an efficient oxidation through to methanesulfonate. This adds a significant pathway to the gas-phase production of methanesulfonic acid, which is present largely in the submicron aerosol fraction. Peak summer concentrations are 0.6 0.3 nmol m and at times this can amount to almost a quarter of the non-seasalt sulfate in the remote marine atmosphere (Jourdain and Legrand, 2001). 

Luria, M. and Sievering, H. (1991). Heterogeneous and Homogeneous Oxidation of S02 in the Remote Marine Atmosphere. Atmos. Environ. 25A(8), 1489-1496. 

Dimethyl sulphide (CH3SCH3, DMS) is the dominant natural sulphur eompound emitted from the world s oeeans (Berresheim et ai, 1995, Urbanski and Wine, 1999), accounting for about one quarter of global sulphur gas emissions. Oceanic DMS, through its oxidation products, is proposed to play a key role in climate regulation, especially in the remote marine atmosphere (Charlson et al, 1987). 

Davision, B. M. and Allen, A. G., A method for sampling dimethylsulfide in polluted and remote marine atmospheres, Atmos. Environ., 28, 1721-1729, 1994. 

On the contrary, low number scavenging efficiencies are expected in clouds influenced by anthropogenic sources because of the prevalence of fine aerosol particles number scavenging efficiencies of a few percent or less are expected in most such situations. Only in clouds in the remote marine atmosphere does the total number scavenging efficiency exceed 0.1. 

Effect of cloud processing of aerosols in the remote marine atmosphere has been demonstrated in a series of field studies (Hoppel et al. 1986 Frick and Hoppel 1993). Figure 17.23 shows the formation of a second peak in the accumulation mode as an airmass is advected off North America to the Atlantic and the Pacific Oceans. Note that the two modes observed in the number distribution should not be confused with modes of the... 

The presence of amino acids in aerosols has been noted for many years [119], but relatively little is known about these or other nitrogen-containing compounds in the atmosphere. A recent review of analyses of marine rainwater shows that marine aerosol particles may contain substantial levels of free and combined amino acids [120], as much as 6.5 pmol in one study [119]. The most likely source in the remote marine atmosphere is the injection of protein... 

Arimoto R, Ray BJ, Duce RA et al (1990) Concentrations, sources, and fluxes of trace-elements in the remote marine atmosphere of New Zealand. J Geophys Res 95 22389-22405 Arimoto R, Duce RA, Savoie DL et al (1992) Trace-elements in aerosol-particles from Bermuda and Barbados—concentrations, sources and relationships to aerosol sulfate. J Atmos Chem 14 439 57... 

Kawamura K. and Gagosian R. B. (1987) Implications of M-oxocarboxyUc acids in the remote marine atmosphere for photo-oxidation of unsaturated fatty acids. Nature 325, 330-332. 

Luria M. and Sievering H. (1991) Heterogeneous and homo- geneous oxidation of SO2 in the remote marine atmosphere. Atmospheric Environment 25A, 1489-1496 Lutgens, F. K., E. J. Tarbuck and D. Tasa (2009) The atmosphere An introduction to meteorology. IF edition. Prentice Hall, Toronto, 544 pp. 

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