Research goals

The oceans produce a diverse array of gases that have a major impact on the chemistry of the atmosphere and the climate system. Our research goal is to understand the factors controlling the production, emissions, and atmospheric chemistry of oceanic trace gases. We develop analytical instruments for trace gas measurement, collect field data from islands, ships, or aircraft, and use computer models to simulate natural processes.

We are also interested in understanding the history of trace gas/climate interactions. Air bubbles trapped in deep polar ice cores from Greenland and Antarctica provide a sample of the ancient atmosphere, and chemicals dissolved in ice contain a record of ancient aerosols. Our ice core studies involve field sampling and laboratory analysis of polar ice cores and air trapped in polar snow.

These trace gases include:

• dimethysulfide - a sulfur gas produced by oceanic phytoplankton, which is a precursor for atmospheric sulfate aerosols, and cloud condensation nucleii in the marine atmosphere.

• carbonyl sulfide - the most abundant sulfur gas in the atmosphere, a precursor for stratospheric sulfate, and a promising tracer for photosynthetic activity.

• alkyl nitrates - these gases are produced photochemically in the surface oceans by "smog-type" reactions. In marine air they are precursors of reactive nitrogen, and influence tropospheric ozone levels over remote oceanic regions.

• alkanes and acetone - hydrocarbons that influence the oxidation capacity of the troposphere.

• methyl halides - gases such as methyl bromide, methyl chloride, etc. which are major sources of stratospheric bromine and chlorine. These gases are both produced and destroyed in the oceans.

• dihalogens (Cl₂, Br₂, I₂, BrCl) - these short-lived gases are produced by reactions of marine aerosols. They are precursors of reactive chlorine and bromine atoms which may influence the reactivity of marine air and the atmospheric lifetimes of other trace gases, such as methane.