After being awarded a technical degree in 1995 from the Institut des Sciences et des Techniques de la Mer (Cherbourg, France), I worked for two years as a research assistant at the University of Nantes, France (Prof J.-M. Robert). My main duty was to isolate and characterise diatoms presenting a potential economical interest and therefore, during this period, I developed skills on the culturing of micro-organisms and their taxonomy. Since 1999, I have worked in the School of Earth, Ocean and Environmental Sciences (University of Plymouth). As a research assistant (1999-2000), I took part in a study of unusual C25 and C30 Highly Branched Isoprenoid (HBI) alkenes synthesised by diatoms, and therefore isolated, identified and cultured a large number of diatom species. This work enabled the structures of numerous C25 and C30 isomers previously reported in sediments to be fully characterised. The influence of environmental parameters on the synthesis of the HBIs by diatom was also investigated. During the course of my PhD studies (2000-2002), I studied the biosynthetic mechanisms leading to the formation of isoprenoids in diatoms as well as the biological factors controlling their production and distribution within three diatom species. I also undertook postdoctoral research with Dr. Belt at the University of Plymouth (NERC funded) investigating the presence of polyprenyl phosphate lipids in diatoms and their potential functions as primitive membrane constituents. I was appointed to a New-Blood lectureship at the University of Plymouth in August 2003. Project Outline: Significant changes in global climate are predicted for the future, which, given their potential socio-economic impacts requires an urgent understanding of the extent, rate and frequency of climate changes in the past so as to allow improved models to be formulated. Polar oceans, in particular sea-ice cover, have been shown to be important contributors to the Earth?s climate and must be considered in reconstructions of the past climatic evolutions. Historically, such reconstructions have been attempted using a range of physical and chemical proxies, even though many of these suffer from limitations. The current project aims to address these limitations by investigating a new geochemical technique. Highly branched isoprenoids are a class of chemicals which, unusually are preserved in polar sediments. In addition, these chemicals are only produced by a few diatom species (Haslea), which are associated with sea-ice. As such, it can be postulated that the presence of HBIs in polar sediments reflect the presence of sea-ice associated diatom species and therefore, should be a good proxy for past sea ice levels.
Membre d’un projet
Cartographie du fond marin de l'Arctique canadien : contributions à la science des changements planétaires, au développement durable des ressources, à la navigation sécuritaire dans le passage du Nord-Ouest, aux risques géologiques et à la souveraineté dans l'Arctique
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