Chemical analyses of seawater provide the first direct evidence that the ocean may be a significant source of certain atmospheric gases that scientists had previously assumed to be produced primarily by industrial activity.
The two gases–methyl nitrate and ethyl nitrate–are members of a group called alkyl nitrates. Such substances consist of a nitrate ion chemically bonded to a hydrocarbon molecule that's lost one of its hydrogen atoms. Forest fires and the burning of fossil fuels produce alkyl nitrates, which react with other atmospheric gases in sunlight to form urban smog (SN: 6/1/02, p. 346: The Air That's Up There). Alkyl nitrates also influence the amount of ozone in the lower atmosphere over remote ocean areas, says Peter S. Liss, an atmospheric scientist at the University of East Anglia in Norfolk, England.