Dr Denise Smythe-Wright

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Emeritus Fellow
Ocean Biogeochemistry and Ecosystems



My current research interests centre on the oceanic sources and sinks of a number of environmentally important gases. I am particularly concerned about the fate of halocarbons but I have also been involved in studies of DMS and nitrous oxide.

My main focus is to better understand the distribution of trace gases in the ocean and their exchange with the atmosphere and the biological and chemical processes that cause trace gas production. Both aspects are fundamental to atmospheric chemistry and our ability to develop accurate climate prediction models. Halogen atoms in the atmosphere are though to both force and mitigate climate change. For example, we now know that the tropical ocean is a major source of methyl iodide and once released to the atmosphere this compound like other volatile iodocompounds undergoes a series of reactions that can lead to the formation of cloud condensation nuclei. Such cloud formation may act against global warming and mitigate it, but the processes involved and their extent is presently unknown.

My work with trace gases has also given me an interest in phytoplankton community structure. My main area of research is the use of plant pigments and their degradation products as biomarkers for specific phytoplankton groups. By looking at pigment ratios and abundances in the ocean we are able to discern which phytoplankton species are abundant at a given time. It is also possible to look at pigments with ocean colour satellites and I am working towards establishing a link between ocean colour and trace gas release in the ocean, although at present the link is rather tenuous.

While most of my research has been conducted at sea on research vessels or with laboratory culture and mesocosm studies, I have recently become involved in using ships of opportunity. At present we have an automated trace gas system on the Pride of Bilbao ferry, which runs from Portsmouth to Bilbao, Spain twice a week. This is giving both trace gas and biological community structure data at very high resolution and is enabling us to better determine the flux of more then 20 trace gases from the ocean to the atmosphere as well as helping us to understand seasonal phytoplankton succession.