As the cruise was leading us into cold, productive waters at the end of the austral summer, we tried to either verify or refute the outcome of some recently published atmospheric models that predict this type of oceanic regime to be a major source for atmospheric methyl bromide. Despite the undersaturations that we found in the open oceans on BLAST I and II, these models predicted supersaturations on the order of hundreds of percent in cold waters. As oceanic degradation due to hydrolysis and nucleophilic displacement is naturally supressed (low temperatures), the high biological productivity observed in those areas were thought to cause high levels of methyl bromide to be released to the atmosphere. The results of this cruise show large undersaturations of methyl bromide, indicating that polar oceans - and, hence, the global oceans - are a net sink for atmospheric methyl bromide. Those results were published in January, 1997, see publications list.
Gas chromatograph / mass spectrometer combination: | |
HCFC-22 | CHClF2 |
CFC-12 | CCl2F2 |
Methyl chloride | CH3Cl |
CFC-114 | C2Cl2F4 |
Halon-1211 | CBrClF2 |
Methyl bromide | CH3Br |
CFC-11 | CCl3F |
Methyl iodide | CH3I |
Methyl chloroform | CH3CCl3 |
Carbon tetrachloride | CCl4 |
Dibromomethane | CH2Br2 |
Perchloroethylene (PCE) | C2Cl4 |
Bromoform | CHBr3 |
Gas chromatograph / electron capture detector combination with various columns and configurations: | |
Methyl bromide | CH3Br |
CFC-12 | CCl2F2 |
Methyl chloride | CH3Cl |
Shari and Jürgen in front of our home lab.
The Nathanial Palmer is operated by Antarctic
Support Associates, which headquarters is located in Englewood, Colorado.
Look up their site to learn more about the Nathanial Palmer and ASA activities.
.
BLAST III is shown in green in the Southern Ocean, out of Antarctica and into southern Chile.