| Abstract | We studied hydrochemistry and plankton dynamics in two remote Alpine lakes: lake Nivolet superiore (2530 m asl) and lake Trebecchi superiore (2729 m asl) in the Gran Paradiso National Park (Western Italian Alps) in summer 2009. The aim of this study was to enhance the understanding of natural ecological dynamics in the pelagic habitat of Alpine lakes by enlarging the number of biotic and abiotic variables usually considered to this end and by increasing the frequency of samplings, generally low in remote lakes. During the eight samplings performed in 2009, chemical and physical variables were measured both in situ and in the laboratory. We also followed the dynamics of all the compartments of the naturally simplified trophic chain of the two lakes from pico-prokaryotes to phytoplankton and zooplankton. Our results confirm the oligotrophic, close-to-pristine state of lake Nivolet and lake Trebecchi as they are not affected by hydromorphological alterations, they are naturally fishless and are not sensitive to acidification risk and acidity pulses. On the other hand, the two lakes have distinct abiotic conditions due to their glacial origin and to the lithological composition of their watersheds. We found some differences in the spatial variation of pico-prokaryotes, phytoplankton and zooplankton due to the different mixing regimes and maximum depth of the two lakes. Conversely, temporal patterns were similar in both lakes, related to ecological interactions and to changes in the abiotic conditions. The rapid succession of events in extreme ecosystems, such as the Alpine lakes studied here, confirm the predominant role of external environmental factors (e.g., the duration of the ice-free season) and of ecological interactions among different trophic compartments. This research underlines the importance of seasonal niche partitioning among organisms with different size. |
| Text | 277362 2013 10.4081/jlimnol.2013.e33 ISI Web of Science WOS 000326626700001 lake chemistry bacteria phytoplankton zooplankton Gran Paradiso National Park Ecological dynamics of two remote Alpine lakes during ice free season Rocco Tiberti; Sabino Metta; Martina Austoni; Cristiana Callieri; Giuseppe Morabito; Aldo Marchetto; Michela Rogora; Gabriele Tartari; Jost Von Hardensberg; Antonello Provenzale Tiberti, Rocco Dipartimento di Scienze della Terra e dell Ambiente, Universita di Pavia; Metta, Sabino Istituto di Scienze dell Atmosfera e del Clima, Consiglio Nazionale delle Ricerche, ISAC CNR, Corso Fiume 4, 10133 Torino; Austoni, Martina Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Callieri, Cristiana Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Morabito, Giuseppe Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Marchetto, Aldo Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Rogora, Michela Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Tartari, Gabriele Istituto per lo studio degli ecosistemi, Consiglio Nazionale delle Ricerche, ISE CNR, Largo Vittorio Tonolli 50, 28922 Verbania Pallanza, Italy; Von Hardensberg, Jost Istituto di Scienze dell Atmosfera e del Clima, Consiglio Nazionale delle Ricerche, ISAC CNR, Corso Fiume 4, 10133 Torino; Provenzale, Antonello Istituto di Scienze dell Atmosfera e del Clima, Consiglio Nazionale delle Ricerche, ISAC CNR, Corso Fiume 4, 10133 Torino We studied hydrochemistry and plankton dynamics in two remote Alpine lakes lake Nivolet superiore 2530 m asl and lake Trebecchi superiore 2729 m asl in the Gran Paradiso National Park Western Italian Alps in summer 2009. The aim of this study was to enhance the understanding of natural ecological dynamics in the pelagic habitat of Alpine lakes by enlarging the number of biotic and abiotic variables usually considered to this end and by increasing the frequency of samplings, generally low in remote lakes. During the eight samplings performed in 2009, chemical and physical variables were measured both in situ and in the laboratory. We also followed the dynamics of all the compartments of the naturally simplified trophic chain of the two lakes from pico prokaryotes to phytoplankton and zooplankton. Our results confirm the oligotrophic, close to pristine state of lake Nivolet and lake Trebecchi as they are not affected by hydromorphological alterations, they are naturally fishless and are not sensitive to acidification risk and acidity pulses. On the other hand, the two lakes have distinct abiotic conditions due to their glacial origin and to the lithological composition of their watersheds. We found some differences in the spatial variation of pico prokaryotes, phytoplankton and zooplankton due to the different mixing regimes and maximum depth of the two lakes. Conversely, temporal patterns were similar in both lakes, related to ecological interactions and to changes in the abiotic conditions. The rapid succession of events in extreme ecosystems, such as the Alpine lakes studied here, confirm the predominant role of external environmental factors e.g., the duration of the ice free season and of ecological interactions among different trophic compartments. This research underlines the importance of seasonal niche partitioning among organisms with different size. 72 Ecological dynamics of two remote Alpine lakes during ice free season tiberti2013_jl.pdf Articolo in rivista Istituto per lo Studio degli Ecosistemi. 1129 5767 Journal of limnology Testo stamp. Journal of limnology Testo stamp. J. limnol. Testo stamp. Journal of limnology. Testo stamp. martina.austoni AUSTONI MARTINA METTA SABINO cristiana.callieri CALLIERI CRISTIANA aldo.marchetto MARCHETTO ALDO giuseppe.morabito MORABITO GIUSEPPE michela.rogora ROGORA MICHELA jostdiedrich.grafvonhardenberg GRAF VON HARDENBERG JOST DIEDRICH antonello.provenzale PROVENZALE ANTONELLO gabriele.tartari TARTARI GABRIELE ACQWA Assessment of Climatic change and impacts on the Quantity and quality of Water TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici TA.P02.011.004 Modellistica climatica, ricostruzione del clima e delle sue variazioni e valutazione degli impatti |
