Jorijntje Henderiks joined my research group as a rather young graduate student in February 1997 with very high recommendations by her former M.S. supervisors Jan van Hinte and Wolfgang Schlager at the FrijeUniversiteit Amsterdam. While here at the ETH she has pursued her PhD study program in the framework of the EC-funded CANIGO project (MAST III). Early in 2001 she has submitted and defended with high marks her doctoral thesis "Coccolith studies in the Canary basin: glacial-interglacial paleoceanography of the eastern boundary current system". I have also been in the field and on Meteor Cruise M42-4 with J. Henderiks and thus know that she is a top performer also under practical circumstances. J. Henderiks is an exceptionally talented young scientist and ranks overall in the top 10% of all graduate students I have supervised and co-supervised. I consider her thesis as among the top 2 presented so far in our department this year. She is a highly intelligent, competitive and articulate young scientist, who has worked rather independently and enthusiastically on her research projects. She is well organized and has always delivered manuscript drafts, posters and scientific presentations of an exceptional quality and perfection. This has also been recognized at various workshops and conferences, where she has won two awards for her outstanding posters and talks. Her thesis research has resulted in a detailed high-resolution stratigraphic and chronologic analysis of several late Pleistocene sediment cores of the Canary basin and a determination of the glacial-interglacial variability of the fluxes of relevant particles (Henderiks et al., in press). In a second part she has used coccolith abundance variability and coccolith accumulation rate changes to reconstruct the regional current and fertility patterns in the last two glacial-interglacial cycles. In the truly innovative third and fourth chapters she has successfully used and applied morphological measurements of coccoliths belonging to the Gephyrocapsa and Calcidiscus complex to derive regional temperature and fertility transfer-functions and reconstructed the paleoceanography of the last glacial maximum. In related studies carried out in the EC- TMR project CODENET, it has just been shown, that the morphotypes are biologically distinct species and that J.Henderiks' use of morphotype abundances and measurements may represent much more reliable paleo-proxies than hitherto possible with lumped species abundance data. An additional advantage of morphometrically based paleo-proxies lies in their lesser dependence on carbonate dissolution. Her proposed project addresses a very fundamental and poorly known question of geobiology: the relationship between the evolutionary history of the major calcareous plankton groups (planktic foraminifer and coccolithophores) and deep-sea carbonate sinks in the past 200 million years. The project will further J.Henderiks' capabilities and potential for a successful future career in geobiology and paleoceanography for which I consider her highly qualified.