Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Increase in photosynthetic efficiency as a strategy of planktonic organisms exploiting deep lake layers |
| Abstract | 1.The photosynthetic efficiencies of the mixotrophic ciliate Ophrydium naumanni and the autotrophic dinoflagellate Gymnodinium paradoxum were investigated using laboratory and field experiments in Lake Moreno Oeste (41°5'S and 71°33'W, 758 m a.s.l.), in the Nahuel Huapi System (North Patagonia, Argentina). 2. The effect of different underwater light intensities on net primary production (NPP) was assessed during one summer. Additionally, laboratory experiments were carried out to obtain photosynthesis-irradiance response curves for each species. 3. Ophrydium naumanni and G. paradoxum dominated the metalimnetic (30 m depth) deep chlorophyll maximum (DCM) in the lake. 4. Despite these deep higher abundances, the cell-specific production of both species was higher at 10 m than at 30 m (DCM) depth. In addition, at 5 m depth, NPP was reduced by PAR + UV-A radiation. 5. Both species exhibited a positive NPP at very low irradiance but the mixotrophic ciliate was more efficient in exploiting the DCM irradiance level both in situ and at comparable light intensities in laboratory experiments. Light acclimatised O. naumanni showed a higher NPP at lower irradiances and photoinhibition at medium and high irradiances. 6. Under the strong wind-driven turbulence commonly found in Patagonian lakes, organisms cannot select their position in the epilimnetic water column and will be dragged to potentially harmful UV radiation levels. Thus, metalimnetic DCM colonisation by these two species represents a tradeoff between higher survival and lower cell-specific NPP. |
| Source | Freshwater biology (Print) 49, pp. 160–169 |
| Journal | Freshwater biology (Print) |
| Editor | Blackwell Scientific Publications., Edinburgh, Regno Unito |
| Year | 2004 |
| Type | Articolo in rivista |
| DOI | 10.1046/j.1365-2427.2003.01169.x |
| Authors | Modenutti B.(1), Balseiro E.(1), Callieri C., Queimaliños C.(1), Bertoni R. |
| Text | 52827 2004 10.1046/j.1365 2427.2003.01169.x ISI Web of Science WOS 000188224600003 Increase in photosynthetic efficiency as a strategy of planktonic organisms exploiting deep lake layers Modenutti B. 1 , Balseiro E. 1 , Callieri C., Queimaliños C. 1 , Bertoni R. 1 Laboratory of Limnology, Centro Regional Universitario Bariloche Universidad Nacional del Comahue, Quintral, Bariloche, Argentina 1.The photosynthetic efficiencies of the mixotrophic ciliate Ophrydium naumanni and the autotrophic dinoflagellate Gymnodinium paradoxum were investigated using laboratory and field experiments in Lake Moreno Oeste 41°5 S and 71°33 W, 758 m a.s.l. , in the Nahuel Huapi System North Patagonia, Argentina . 2. The effect of different underwater light intensities on net primary production NPP was assessed during one summer. Additionally, laboratory experiments were carried out to obtain photosynthesis irradiance response curves for each species. 3. Ophrydium naumanni and G. paradoxum dominated the metalimnetic 30 m depth deep chlorophyll maximum DCM in the lake. 4. Despite these deep higher abundances, the cell specific production of both species was higher at 10 m than at 30 m DCM depth. In addition, at 5 m depth, NPP was reduced by PAR UV A radiation. 5. Both species exhibited a positive NPP at very low irradiance but the mixotrophic ciliate was more efficient in exploiting the DCM irradiance level both in situ and at comparable light intensities in laboratory experiments. Light acclimatised O. naumanni showed a higher NPP at lower irradiances and photoinhibition at medium and high irradiances. 6. Under the strong wind driven turbulence commonly found in Patagonian lakes, organisms cannot select their position in the epilimnetic water column and will be dragged to potentially harmful UV radiation levels. Thus, metalimnetic DCM colonisation by these two species represents a tradeoff between higher survival and lower cell specific NPP. 49 Articolo pubblicato 5_Modenutti_et_al_2004_FBiol.pdf Articolo in rivista Blackwell Scientific Publications. 0046 5070 Freshwater biology Print Freshwater biology Print Freshw. biol. Print roberto.bertoni BERTONI ROBERTO cristiana.callieri CALLIERI CRISTIANA TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |