| SS4.02 Ecology and Physiology of Marine Organisms: Insights from Genes, Genomes, and Proteomes |
| Teira, E, , Royal Netherlands Institute for Sea Research, DenBurg, Netherlands, teira@nioz.nl |
| Herndl, G, J, Royal Netherlands Institute for Sea Research, DenBurg, Netherlands, herndl@nioz.nl |
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| UPTAKE OF D- VS. L- AMINO ACIDS BY THE MAIN PROKARYOTES IN THE MESO- AND BATHYPELAGIC WATERS OF THE NORTH ATLANTIC |
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| Only recently, fluorescence in situ hybridization (FISH) became sufficiently sensitive to allow the enumeration of prokaryotes even in oligotrophic and deep waters by using catalyzed reporter deposition (CARD-FISH). Using this method in combination with microautoradiography, we determined the uptake of D- vs. L-aspartic acid (asp) by the major prokaryotic groups (Bacteria, Eury- and Crenarchaeota) in samples collected in the North Atlantic between 100m and 4,500m depth. Recently, it has been reported that the prokaryotic D-/L-asp uptake ratio for the bulk community increases by 2-3 orders of magnitude from the surface to bathypelagic waters. Thus our overall goal was to identify the prokaryotic group responsible for this shift in the D-/L- asp uptake ratio with depth. Our data indicate that Archaea are both more abundant (about 40% of DAPI stained cells) than Bacteria (30% of DAPI) and more active (60% vs 40% of active cells) in meso- and bathypelagic waters. The previously reported increase of the D-/L-asp uptake ratio with depth is mainly due to an increase in the ratio of D-/L-asp uptake by Crenarchaeota towards the ocean’s interior. |
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