Objectif Prokaryotic plankton are the principal mediators of the biogeochemical fluxes in the ocean.The deep ocean has been considered for a long time to be of minor importance for these fluxes.Recent modelling approaches, however, indicate that about 30 percent of the oceanic remineralization is mediated in the meso- and bathypelagic ocean.Prokaryotic rates have rarely been measured in the deep ocean and if they were measured, then under decompressed conditions i.e. surface pressure.There are indications, however, that decompression might severely affect the metabolic rates.In this project, we aim to determine prokaryotic production measurements as a estimation for total prokaryotic biomass under in situ pressure conditions and compared with samples held at decompr essed conditions.Procaryotic production will be measured via incorporation of radiolabelled leucine into prokaryotic biomass and Archaea production via radiolabelled bicarbonate incorporation.Secondly we will determine single cell activity using a modifie d version of the recently developed catalyzed reporter deposition in situ fluorescence hybridization with specific oligonucleotide probes combined with microautoradiography (MICRO-CARD-FISH).Cells taking up radiolabelled substances are surrounded by a silv er-grain halo, which can be quantify by image analysis and epifluorescence microscopy.While this method has been used only qualitatively, the product of size and intensity of the halo should reflect the metabolic activity.Using this approach, we will dete rmine the relative contribution of individual bacterial and Archaea species to the total prokaryotic biomass production in different depth layers of the North Atlantic.Also we will obtain information on the intraspecific differences in the activity of the dominant prokaryotic species.The project will provide essential and novel information on deep water prokaryotic activity and has the potential to alter our view of the role of the ocean in the global carbon cycling. Champ scientifique natural sciencesbiological sciencesmicrobiologybacteriologyagricultural sciencesagricultural biotechnologybiomass Mots‑clés Archaea Bacteria Biogeochemical cycles Marine prokaryotes Programme(s) FP6-MOBILITY - Human resources and Mobility in the specific programme for research, technological development and demonstration "Structuring the European Research Area" under the Sixth Framework Programme 2002-2006 Thème(s) MOBILITY-2.1 - Marie Curie Intra-European Fellowships (EIF) Appel à propositions FP6-2004-MOBILITY-5 Voir d’autres projets de cet appel Régime de financement SCF - Marie Curie actions-Series of events Coordinateur STICHTING KONINKLIJK NEDERLANDS INSTITUUT VOOR ONDERZOEK DER ZEE Contribution de l’UE Aucune donnée Adresse Landsdiep 4 DEN BURG Pays-Bas Voir sur la carte Liens Site web Opens in new window Coût total Aucune donnée
