Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Picocyanobacteria photosynthetic efficiency under Daphnia grazing pressure |
| Abstract | Daphnia hyalina was used to assess the impact of zooplankton on the photosynthetic activity of picocyanobacteria. A phosphorus-limited laboratory system was designed, composed of 3µm filtered lake water with natural assemblages to which non-axenic Synechococcus sp. was added. Different treatments with and without Daphnia were arranged; aliquots from these were sampled during 3-day incubations to measure changes in picocyanobacterial net primary production (NPP), excreted organic carbon (EOC), dissolved organic carbon (DOC) and photosynthetic parameters (photosynthesis- irradiance response curves). Bacterial number, biovolume and production were measured in both the treatment and control to evaluate possible bacterial interferences. A significant increase of picocyanobacterial photosynthesis and efficiency (2- and 3-fold increase of Pmax and alfa respectively) was observed in bottles supplemented with Daphnia, whereas cell-specific bacterial production did not. At the same time, the EOC:NPP ratio was 2.3 times lower with the grazer. This result clearly shows the impact of P recycling mediated by a grazer on picocyanobacterial growth and production. |
| Source | Journal of plankton research 26, pp. 1471–1477 |
| Keywords | ----------------------- |
| Journal | Journal of plankton research |
| Editor | Information Retrieval Inc.],, [New York,, Stati Uniti d'America |
| Year | 2004 |
| Type | Articolo in rivista |
| Authors | Callieri C., Balseiro E.(1), Bertoni R., Modenutti B.(1) |
| Text | 52826 2004 Picocyanobacteria photosynthetic efficiency under Daphnia grazing pressure Callieri C., Balseiro E. 1 , Bertoni R., Modenutti B. 1 1 CONICET, Univ. Nacional del Comahue, Lab. de Limnologia, Bariloche, Argentina Daphnia hyalina was used to assess the impact of zooplankton on the photosynthetic activity of picocyanobacteria. A phosphorus limited laboratory system was designed, composed of 3µm filtered lake water with natural assemblages to which non axenic Synechococcus sp. was added. Different treatments with and without Daphnia were arranged; aliquots from these were sampled during 3 day incubations to measure changes in picocyanobacterial net primary production NPP , excreted organic carbon EOC , dissolved organic carbon DOC and photosynthetic parameters photosynthesis irradiance response curves . Bacterial number, biovolume and production were measured in both the treatment and control to evaluate possible bacterial interferences. A significant increase of picocyanobacterial photosynthesis and efficiency 2 and 3 fold increase of Pmax and alfa respectively was observed in bottles supplemented with Daphnia, whereas cell specific bacterial production did not. At the same time, the EOC NPP ratio was 2.3 times lower with the grazer. This result clearly shows the impact of P recycling mediated by a grazer on picocyanobacterial growth and production. 26 Published version Articolo pubblicato 12_Callieri_et_al_2004_JPRes.pdf Articolo in rivista Information Retrieval Inc. , 0142 7873 Journal of plankton research Journal of plankton research J. plankton res. Journal of plankton research. roberto.bertoni BERTONI ROBERTO cristiana.callieri CALLIERI CRISTIANA TA.P02.005.002 Uso della paleolimnologia come strumento per lo studio del paleoclima e dell evoluzione climatica |