Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Bacterial invasion and protozoan grazing increase transfer efficiencies of polymeric organic matter in microbial model systems |
| Abstract | Refractory polymeric matter contributes the majority to organic carbon in freshwater, but their bacterial utilization remains unresolved. Our lack in knowledge is mainly based on the fact that degradation experiments predominantly use bacterial pure cultures and thereby neglect the multitude of organismic interactions and feedback mechanisms of complex, natural systems. By using simplified aquatic bacterial communities, we tested whether invasions of a competitor, a nanoflagellate predator, or both affect microbial utilization of refractory substrates. Whereas the relative abundance of resident bacterial strains did not change after invasion, the productivity of the systems greatly increased. Introduction of predators resulted in a 5-10 fold increase in bacterial abundances in chitin and cellulose treatments. Concomitantly, bacteria shifted from free-living to an aggregate ecotype which could promote utilization of refractory substrates by syntrophic interactions between bacterial cells. Higher microbial utilization of refractory substrates in an "aggregate meta-metabolism" may occur via local bacterial growth induced by a spatially concentrated release of readily available labile substrates by protozoan grazing. Our model shows that complexity of microbial interactions increases productivity and C transfer efficiency of aquatic ecosystems. The interaction between microbes of different ecological status in a spatially reduced environment (the co-aggregate) could thus be the key factor for chitin and cellulose degradation in waters, as confirmed by our extrapolations on a world scale. Hence, to better understand turnover of the vast pool of refractory polymeric organic matter in natural ecosystems organismic interactions and their feedback mechanisms need to be taken into account. |
| Source | AIOL - XXI Congresso dell'Associazione Italiana di Oceanologia e Limnologia: Limnologia e Oceanografia nel Terzo Millennio: nuove frontiere o assenza di frontiere?, Lignano Sabbiadoro (UD), 23-26 settembre 2013 |
| Keywords | Polymeric organic matterFreshwaterBacterial invasionMicrobial model systemsProtozoan grazing |
| Year | 2013 |
| Type | Abstract in atti di convegno |
| Authors | Gianluca Corno; Ivette Salka; Hans-Peter Grossart |
| Text | 286710 2013 Polymeric organic matter Freshwater Bacterial invasion Microbial model systems Protozoan grazing Bacterial invasion and protozoan grazing increase transfer efficiencies of polymeric organic matter in microbial model systems Gianluca Corno; Ivette Salka; Hans Peter Grossart Corno, Gianluca CNR ISE, Pallanza Verbania Salka, Ivette Grossart, Hans Peter IGB Berlin, Germany XXI Congresso dell Associazione Italiana di Oceanologia e Limnologia Limnologia e Oceanografia nel Terzo Millennio nuove frontiere o assenza di frontiere Published version In AIOL XXI Congresso dell Associazione Italiana di Oceanologia e Limnologia Limnologia e Oceanografia nel Terzo Millennio nuove frontiere o assenza di frontiere Lignano Sabbiadoro UD , 23 26 settembre 2013 . Abstract, pp. 78 78. Associazione Italiana di Oceanologia e Linologia, 2013. AIOL XXI Congresso dell Associazione Italiana di Oceanologia e Limnologia Limnologia e Oceanografia nel Terzo Millennio nuove frontiere o assenza di frontiere Lignano Sabbiadoro UD 23 26 settembre 2013 Nazionale Contributo Refractory polymeric matter contributes the majority to organic carbon in freshwater, but their bacterial utilization remains unresolved. Our lack in knowledge is mainly based on the fact that degradation experiments predominantly use bacterial pure cultures and thereby neglect the multitude of organismic interactions and feedback mechanisms of complex, natural systems. By using simplified aquatic bacterial communities, we tested whether invasions of a competitor, a nanoflagellate predator, or both affect microbial utilization of refractory substrates. Whereas the relative abundance of resident bacterial strains did not change after invasion, the productivity of the systems greatly increased. Introduction of predators resulted in a 5 10 fold increase in bacterial abundances in chitin and cellulose treatments. Concomitantly, bacteria shifted from free living to an aggregate ecotype which could promote utilization of refractory substrates by syntrophic interactions between bacterial cells. Higher microbial utilization of refractory substrates in an aggregate meta metabolism may occur via local bacterial growth induced by a spatially concentrated release of readily available labile substrates by protozoan grazing. Our model shows that complexity of microbial interactions increases productivity and C transfer efficiency of aquatic ecosystems. The interaction between microbes of different ecological status in a spatially reduced environment the co aggregate could thus be the key factor for chitin and cellulose degradation in waters, as confirmed by our extrapolations on a world scale. Hence, to better understand turnover of the vast pool of refractory polymeric organic matter in natural ecosystems organismic interactions and their feedback mechanisms need to be taken into account. Abstract 2013_Abstract_AIOL_Corno.pdf Abstract in atti di convegno gianluca.corno CORNO GIANLUCA TA.P04.016.004 Ecologia teorica e applicata degli ecosistemi acquatici |