COCCOLITHOPHORID DYNAMICS - THE EUROPEAN EMILIANIA-HUXLEYI PROGRAM, EHUX

The achievements of the MAST II funded EHUX project, an interdisciplin ary study of the coccolithophorid Emiliania huxleyi are briefly review ed, A collection of over 300 clones of E. huxleyi has been maintained to support research on coccolithophorid morphology, physiology, molecu lar genetics, and the life cycle. Laboratory cultures have also been u sed for investigations of calcification and calcification gene identif ication. The photobiology of E. huxleyi, interactions between producti vity and the environment, and coccolithophorid growth and production h ave been studied both in the laboratory and in the Northern North Sea, the latter work being guided by remote sensing. Integrated investigat ions have been made of the synthesis and degradation of lipid biomarke rs produced by E. huxleyi, the formation and microbial degradation of aggregates, and zooplankton grazing and mortality. An extensive progra mme of mesocosm studies has been carried out with special emphasis on the population dynamics of E. huxleyi, the coupling between calcificat ion and nutrient supply, and the role of viruses in population dynamic s. Mathematical simulation models of mesocosm bloom dynamics have been developed, first attempts have been made to develop cell biological m odels of E. huxleyi, and a model which predicts the timing and magnitu des of blooms of E. huxleyi with particular reference to the seasonal succession in the North Atlantic has been developed.