Archive for February, 2012
Today’s Geochemical Luncheon Club seminar had the pleasure of welcoming two guest speakers from the University of Heidelberg, Nicole Bobrowski and Leif Vogel. The topic of the talk was Bromine Chemistry in Volcanic Plumes – a hot topic (no pun intended) of atmospheric science. In 2003, with measurements taken at the Soufrière Hills volcano in Montserrat, Dr. Bobrowski published the first measurements of bromine oxide (BrO) in a volcanic plume.
Discussing the gases that are produced by volcanoes, the seminar began with a brief overview of volcanic atmospheric science – how gas emissions vary between the different volcanic types, are ultimately the source of both our current atmosphere and the oceans and the critical role played by volcanoes in the global carbon cycle over geological timescales.
The principal point of discussion was the volcanic emission of halogens, principally bromine. Whilst halogens have been known to be found in volcanic plumes since the 19th century, it is only very recently that they have been found to be in forms such as BrO that have significant reactivity in the troposphere. Since Dr. Bobrowski’s Soufrière Hills detection, BrO has been detected in the plumes of many volcanoes worldwide. These observations, coupled with modelling studies of the reaction sequence known as the “bromine explosion”, have changed the long-held view of volcanic plumes as largely inert entities. The talk continued discussing the various measurement techniques that are employed to measure the chemical content of volcanic plumes were discussed.
What factors govern the BrO content of volcanic plumes is not yet fully known, and is an area of active research for many scientists. Results from recent campaigns and computer models seeking to investigate these origins were also presented.
This summer UEA researchers will join our speakers and researchers from other institutions on a field campaign to Mount Etna, investigating, amongst other questions, some of the outstanding unknowns in the field of volcanic halogens.