Assodato che il cambiamento climatico è in corso, molte sono ancora le incertezze sulla conseguen... more Assodato che il cambiamento climatico è in corso, molte sono ancora le incertezze sulla conseguente risposta da parte degli ecosistemi, in particolare di quelli acquatici. Come emerso sia dall’analisi delle serie storiche di dati, sia da indagini paleolimnologiche, questi ambienti, a differenza di quelli terrestri, presentano dei meccanismi di riposta più complessi, spesso non lineari, o no riconducibili ad una semplice relazione causa-effetto. Sono qui discussi esempi o casi di studio che evidenziano come le comunità biologiche che vivono in ambienti acquatici abbiamo strutture peculiari e come queste caratteristiche siano rispondano agli impatti climatici. Per valutare in modo appropriato quale sarà l’evoluzione di questi ecosistemi nel prossimo futuro è necessario aumentare la conoscenza di questi ambienti su scala sia spaziale sia temporale, in modo da poter discriminare il contributo di fattori locali o globali, antropici o naturali. In questo contesto gli ambienti acquatici de...
Il Lago di Levico (Trentino sudoccidentale) si trova a 440m s.l.m., ha una superficie di 1.16 Km2... more Il Lago di Levico (Trentino sudoccidentale) si trova a 440m s.l.m., ha una superficie di 1.16 Km2, profondità massima di 38 m, e un volume di 12.9 106 m3. Il lago riveste una grande importanza socio-economica quale terzo sito ricreativo estivo trentino dopo i laghi di Garda e Caldonazzo), ma primo sviluppo della conca di Levico come centro termale risale già ai primi del ‘900. La porzione orientale del lago e tutelata come SIC per la vegetazione e l’avifauna aquatica. Lo studio dei sedimenti profondi del Lago di Levico ha lo scopo di: i) determinare le condizioni ecologiche di riferimento del lago antecedenti l’impatto antropico più intenso; ii) compensare la frammentarietà dei dati limnologici per determinare la vulnerabilità del lago rispetto al crescente impatto antropico in un contesto di cambiamento climatico; iii) affinare gli obiettivi di qualità futuri e promuovere azioni a favore di misure per un uso sostenibile del lago. Vengono qui presentati i primi risultati dello stud...
A comparative study of independent geochemical and biological proxies was carried out on a short ... more A comparative study of independent geochemical and biological proxies was carried out on a short (83 cm) sediment core collected in 2011 from the deepest point of a small subalpine Lake Ledro (Trentino, N-Italy). The aim of the study is to compare the capability of subfossil photosynthetic pigments, diatoms and Cladocera in tracking lake ecological transitions and tipping points related to major environmental perturbations occurred during the last three centuries, i.e. after the culmination of the Little Ice Age in the Alpine region. In relation to the sparse neo-limnological and climate data available for the lake, the study aims also at defining of the lake trophic and ecological reference conditions, at improving the reconstruction of the nutrient enrichment process during the last decades, and at evaluating the effects of restoration measures initiated in the 1990s. The analysis of the selected proxies outlined a pronounced sensitivity of Lake Ledro to hydrological variability throughout the whole time span considered, especially during the 18 th and 19 th century, and revealed two major stages in the ecological evolution of the lake, which were mainly controlled by climate related hydrological variability and lake nutrients. The results largely agree with the hypothesis that responses of sediment biological proxies to different natural and human stressors may differ in type, timing and magnitude. Subfossil pigments, diatoms and Cladocera showed a comparable capability in tracking ecological transitions and tipping points related to lake hydrology and nutrient variability, while only diatoms demonstrated a certain capability to track changes in water temperature of the lake studied. The strong response of planktonic organisms to hydrological variability depends on the peculiar catchment and lake morphology, and confirmed that planktonic organism principally respond to climate variability in an indirect way. The reconstruction of the trophic development of Lake Ledro during the last decades revealed that the vulnerability of the lake toward climate and land use driven hydrological variability is congenital for the lake, though at present it is masked by nutrients. This stresses the necessity to maintain and improve the control of nutrient inputs also in reoligotrophicated subalpine lakes, in relation to the present context of human use and climate change, and paying particular attention to the lake-specific sensitivity to local forcings.
Lake sediments constitute natural archives of past environmental changes. Historically, research ... more Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeoli...
The main aim of this contribution is to evaluate the vulnerability of Lake Garda, the largest Ita... more The main aim of this contribution is to evaluate the vulnerability of Lake Garda, the largest Italian lake, respect to specific human stressors (e.g. nutrients, hydroelectrical exploitation) in a climate change scenario and through a palaeolimnological approach. Lake's sediments have been studied within the EuLakes project (Reg. Nr. 2CE243P3) and results are being used to determine the lake reference conditions before stronger human impact. The deeper basin (350 m) of the Lake is less impacted by human activities and is suitable for reconstruction of long term environmental variability, including climate change and its effects on lake ecology. In contrast, the shallower basin (81 m) is strongly affected by tourism and intensive agriculture, and thus is more suitable for studies on lake eutrophication. This contribution focusses on changes in sub-fossil diatom assemblages and TP reconstruction of two short sediment cores collected from the deepest point of the two basins. The cor...
Littoral distribution of dinofl agellates in Lake Tovel (Trentino, Italy)-Lake Tovel (Trentino, N... more Littoral distribution of dinofl agellates in Lake Tovel (Trentino, Italy)-Lake Tovel (Trentino, North Italy) has been focus of scientifi c research for more than one century. However, the majority of phytoplankton investigations regarded a few dinofl agellate species in the main basin of the lake. Because of the importance of the littoral region of lakes and microhabitat diversity in originating the dinofl agellates community, we decided to include this area in our study on phytoplankton dynamics and distribution in Lake Tovel. From July to September 2004 we sampled fortnightly both the littoral and pelagic zone of the lake, aiming at the study of dinofl agellates seasonal development. This study has revealed very scarce nutrient variations during the period investigated. Nonetheless, a clear succession of species has been found, which has been attributed to changes in water temperature and hydrodynamics of the lake. Glenodinium sanguineum sensu Dodge (1987) in early summer and Gymnodinium uberrrimum and Baldinia anauniensis gen. inedit. sp. inedit. Hansen et al. (in prep.) later on dominated the community along the period considered. RIASSUNTO Distribuzione litorale dei dinofl agellati nel Lago di Tovel (Trentino, Italia)-Nell'ultimo secolo il Lago di Tovel (Trentino, Nord Italia) è stato oggetto di un'intensa attività di ricerca. Tuttavia, gran parte degli studi riguardanti la comunità fi toplanctonica sono stati focalizzati su alcuni taxa di dinofl agellati presenti nel bacino principale del lago. Per l'importanza delle zone litorali e della diversità dei microhabitat nell'originare la comunità fi toplanctonica lacustre, l'indagine sulla distribuzione e la dinamica del fi toplancton del lago è stata estesa a questi ambienti. Da luglio a fi ne settembre 2004 sono stati effettuati campionamenti ogni due settimane sia nelle zone litorali che pelagiche del lago. Lo studio ha rilevato una scarsa variabilità della concentrazione di nutrienti durante il periodo indagato. Nonostante ciò, è stata osservata una chiara successione di specie dinofl agellate, apparentemente in relazione con variazioni della temperatura dell'acqua e dell'idrodinamica del lago. Durante il periodo considerato, la comunità è stata dominata da Glenodinium sanguineum sensu Dodge all'inizio dell'estate e successivamente da Gymnodinium uberrrimum e Baldinia anauniensis gen. inedit. sp. inedit. Hansen et al. (in prep.).
A survey of phytoplankton and littoral epilithic diatom communities was carried out on 16 high mo... more A survey of phytoplankton and littoral epilithic diatom communities was carried out on 16 high mountain lakes in the Adamello-Brenta Regional Park (NE Italy) as part of a wider research project aimed to the limnological characterisation of the seldom-studied lakes in this Alpine Region. The regional study was supplemented by the analysis of seasonal variations in two representative lakes. The principal goals of this paper are 1) to identify the most important environmental variables regulating patterns in the species composition of both phytoplankton and littoral diatoms, 2) to evaluate whether these algal communities can be used to improve trophic classification and 3) whether they can facilitate monitoring of diffuse human impacts (e.g. airborne pollution) on high altitude lakes. The relevance to monitoring is based on the acid sensitivity of all lakes studied, as indicated by the very low average alkalinity values (4-97 µeq l-1) recorded during the investigation period. Chlorophyll-a concentrations and phytoplankton biovolume recorded in the lakes were very low, with maxima in the deep-water layers and in late summer. Phytoplankton communities were dominated by flagellated algae (Chrysophyceae and Dinophyceae). Several coccal green algae were present, while planktonic diatoms were almost completely absent. Littoral diatom communities were dominated by alpine and acidophilous taxa (mainly belonging to the genera Achnanthes and Eunotia). Trophic classification based on phytoplankton and littoral diatoms, respectively, ascribed all lakes to the oligotrophic range. In both algal communities species indicative of acidified conditions were found. Multivariate analyses indicated that both the regional distribution and seasonal variation of phytoplankton are mainly driven by nutrient concentration. Diatoms are predominantly affected by geochemical characteristics including pH and mineralization level.
Permafrost has become an important issue in the European Alps. In South Tyrol (Italy), the area o... more Permafrost has become an important issue in the European Alps. In South Tyrol (Italy), the area of permafrost covers about 440 km, and in the Austrian Alps about 2000 km. Active rock glaciers are a common feature of high mountain permafrost and due to their location near the lower boundary of permafrost, their mean annual surface temperature is close to melting conditions (Haeberli et al., 2006), which indicates their particular sensitivity to climate warming. Air temperature in the Alps has substantially increased during the past decades and climate warming is projected to become even more pronounced until the end of the 21th century. Increasing instability of slopes, landslides and floods, as well as alterations in the hydrological regime can be anticipated. Up to now, studies on the effects of active rock glaciers on hydrology and water chemistry of adjacent surface waters are still rare (e.g. Williams et al., 2006; Krainer et al., 2007; Thies et al., 2007; Baron et al., 2009). R...
... Author(s): Marchetto, A.; Rogora, M.; Boggero, A.; Musazzi, S.; Lami, A.; Lotter, A.; Tolotti... more ... Author(s): Marchetto, A.; Rogora, M.; Boggero, A.; Musazzi, S.; Lami, A.; Lotter, A.; Tolotti, M.; Thies, H.; Psenner, R.; Massaferro, J.; Barbieri, A. Affiliation FEM: Research and Innovation Centre. ... Citation: Marchetto, A., Rogora, M., Boggero, A., Musazzi, S., Lami, A., Lotter, A., et al. ...
Assodato che il cambiamento climatico è in corso, molte sono ancora le incertezze sulla conseguen... more Assodato che il cambiamento climatico è in corso, molte sono ancora le incertezze sulla conseguente risposta da parte degli ecosistemi, in particolare di quelli acquatici. Come emerso sia dall’analisi delle serie storiche di dati, sia da indagini paleolimnologiche, questi ambienti, a differenza di quelli terrestri, presentano dei meccanismi di riposta più complessi, spesso non lineari, o no riconducibili ad una semplice relazione causa-effetto. Sono qui discussi esempi o casi di studio che evidenziano come le comunità biologiche che vivono in ambienti acquatici abbiamo strutture peculiari e come queste caratteristiche siano rispondano agli impatti climatici. Per valutare in modo appropriato quale sarà l’evoluzione di questi ecosistemi nel prossimo futuro è necessario aumentare la conoscenza di questi ambienti su scala sia spaziale sia temporale, in modo da poter discriminare il contributo di fattori locali o globali, antropici o naturali. In questo contesto gli ambienti acquatici de...
Il Lago di Levico (Trentino sudoccidentale) si trova a 440m s.l.m., ha una superficie di 1.16 Km2... more Il Lago di Levico (Trentino sudoccidentale) si trova a 440m s.l.m., ha una superficie di 1.16 Km2, profondità massima di 38 m, e un volume di 12.9 106 m3. Il lago riveste una grande importanza socio-economica quale terzo sito ricreativo estivo trentino dopo i laghi di Garda e Caldonazzo), ma primo sviluppo della conca di Levico come centro termale risale già ai primi del ‘900. La porzione orientale del lago e tutelata come SIC per la vegetazione e l’avifauna aquatica. Lo studio dei sedimenti profondi del Lago di Levico ha lo scopo di: i) determinare le condizioni ecologiche di riferimento del lago antecedenti l’impatto antropico più intenso; ii) compensare la frammentarietà dei dati limnologici per determinare la vulnerabilità del lago rispetto al crescente impatto antropico in un contesto di cambiamento climatico; iii) affinare gli obiettivi di qualità futuri e promuovere azioni a favore di misure per un uso sostenibile del lago. Vengono qui presentati i primi risultati dello stud...
A comparative study of independent geochemical and biological proxies was carried out on a short ... more A comparative study of independent geochemical and biological proxies was carried out on a short (83 cm) sediment core collected in 2011 from the deepest point of a small subalpine Lake Ledro (Trentino, N-Italy). The aim of the study is to compare the capability of subfossil photosynthetic pigments, diatoms and Cladocera in tracking lake ecological transitions and tipping points related to major environmental perturbations occurred during the last three centuries, i.e. after the culmination of the Little Ice Age in the Alpine region. In relation to the sparse neo-limnological and climate data available for the lake, the study aims also at defining of the lake trophic and ecological reference conditions, at improving the reconstruction of the nutrient enrichment process during the last decades, and at evaluating the effects of restoration measures initiated in the 1990s. The analysis of the selected proxies outlined a pronounced sensitivity of Lake Ledro to hydrological variability throughout the whole time span considered, especially during the 18 th and 19 th century, and revealed two major stages in the ecological evolution of the lake, which were mainly controlled by climate related hydrological variability and lake nutrients. The results largely agree with the hypothesis that responses of sediment biological proxies to different natural and human stressors may differ in type, timing and magnitude. Subfossil pigments, diatoms and Cladocera showed a comparable capability in tracking ecological transitions and tipping points related to lake hydrology and nutrient variability, while only diatoms demonstrated a certain capability to track changes in water temperature of the lake studied. The strong response of planktonic organisms to hydrological variability depends on the peculiar catchment and lake morphology, and confirmed that planktonic organism principally respond to climate variability in an indirect way. The reconstruction of the trophic development of Lake Ledro during the last decades revealed that the vulnerability of the lake toward climate and land use driven hydrological variability is congenital for the lake, though at present it is masked by nutrients. This stresses the necessity to maintain and improve the control of nutrient inputs also in reoligotrophicated subalpine lakes, in relation to the present context of human use and climate change, and paying particular attention to the lake-specific sensitivity to local forcings.
Lake sediments constitute natural archives of past environmental changes. Historically, research ... more Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeoli...
The main aim of this contribution is to evaluate the vulnerability of Lake Garda, the largest Ita... more The main aim of this contribution is to evaluate the vulnerability of Lake Garda, the largest Italian lake, respect to specific human stressors (e.g. nutrients, hydroelectrical exploitation) in a climate change scenario and through a palaeolimnological approach. Lake's sediments have been studied within the EuLakes project (Reg. Nr. 2CE243P3) and results are being used to determine the lake reference conditions before stronger human impact. The deeper basin (350 m) of the Lake is less impacted by human activities and is suitable for reconstruction of long term environmental variability, including climate change and its effects on lake ecology. In contrast, the shallower basin (81 m) is strongly affected by tourism and intensive agriculture, and thus is more suitable for studies on lake eutrophication. This contribution focusses on changes in sub-fossil diatom assemblages and TP reconstruction of two short sediment cores collected from the deepest point of the two basins. The cor...
Littoral distribution of dinofl agellates in Lake Tovel (Trentino, Italy)-Lake Tovel (Trentino, N... more Littoral distribution of dinofl agellates in Lake Tovel (Trentino, Italy)-Lake Tovel (Trentino, North Italy) has been focus of scientifi c research for more than one century. However, the majority of phytoplankton investigations regarded a few dinofl agellate species in the main basin of the lake. Because of the importance of the littoral region of lakes and microhabitat diversity in originating the dinofl agellates community, we decided to include this area in our study on phytoplankton dynamics and distribution in Lake Tovel. From July to September 2004 we sampled fortnightly both the littoral and pelagic zone of the lake, aiming at the study of dinofl agellates seasonal development. This study has revealed very scarce nutrient variations during the period investigated. Nonetheless, a clear succession of species has been found, which has been attributed to changes in water temperature and hydrodynamics of the lake. Glenodinium sanguineum sensu Dodge (1987) in early summer and Gymnodinium uberrrimum and Baldinia anauniensis gen. inedit. sp. inedit. Hansen et al. (in prep.) later on dominated the community along the period considered. RIASSUNTO Distribuzione litorale dei dinofl agellati nel Lago di Tovel (Trentino, Italia)-Nell'ultimo secolo il Lago di Tovel (Trentino, Nord Italia) è stato oggetto di un'intensa attività di ricerca. Tuttavia, gran parte degli studi riguardanti la comunità fi toplanctonica sono stati focalizzati su alcuni taxa di dinofl agellati presenti nel bacino principale del lago. Per l'importanza delle zone litorali e della diversità dei microhabitat nell'originare la comunità fi toplanctonica lacustre, l'indagine sulla distribuzione e la dinamica del fi toplancton del lago è stata estesa a questi ambienti. Da luglio a fi ne settembre 2004 sono stati effettuati campionamenti ogni due settimane sia nelle zone litorali che pelagiche del lago. Lo studio ha rilevato una scarsa variabilità della concentrazione di nutrienti durante il periodo indagato. Nonostante ciò, è stata osservata una chiara successione di specie dinofl agellate, apparentemente in relazione con variazioni della temperatura dell'acqua e dell'idrodinamica del lago. Durante il periodo considerato, la comunità è stata dominata da Glenodinium sanguineum sensu Dodge all'inizio dell'estate e successivamente da Gymnodinium uberrrimum e Baldinia anauniensis gen. inedit. sp. inedit. Hansen et al. (in prep.).
A survey of phytoplankton and littoral epilithic diatom communities was carried out on 16 high mo... more A survey of phytoplankton and littoral epilithic diatom communities was carried out on 16 high mountain lakes in the Adamello-Brenta Regional Park (NE Italy) as part of a wider research project aimed to the limnological characterisation of the seldom-studied lakes in this Alpine Region. The regional study was supplemented by the analysis of seasonal variations in two representative lakes. The principal goals of this paper are 1) to identify the most important environmental variables regulating patterns in the species composition of both phytoplankton and littoral diatoms, 2) to evaluate whether these algal communities can be used to improve trophic classification and 3) whether they can facilitate monitoring of diffuse human impacts (e.g. airborne pollution) on high altitude lakes. The relevance to monitoring is based on the acid sensitivity of all lakes studied, as indicated by the very low average alkalinity values (4-97 µeq l-1) recorded during the investigation period. Chlorophyll-a concentrations and phytoplankton biovolume recorded in the lakes were very low, with maxima in the deep-water layers and in late summer. Phytoplankton communities were dominated by flagellated algae (Chrysophyceae and Dinophyceae). Several coccal green algae were present, while planktonic diatoms were almost completely absent. Littoral diatom communities were dominated by alpine and acidophilous taxa (mainly belonging to the genera Achnanthes and Eunotia). Trophic classification based on phytoplankton and littoral diatoms, respectively, ascribed all lakes to the oligotrophic range. In both algal communities species indicative of acidified conditions were found. Multivariate analyses indicated that both the regional distribution and seasonal variation of phytoplankton are mainly driven by nutrient concentration. Diatoms are predominantly affected by geochemical characteristics including pH and mineralization level.
Permafrost has become an important issue in the European Alps. In South Tyrol (Italy), the area o... more Permafrost has become an important issue in the European Alps. In South Tyrol (Italy), the area of permafrost covers about 440 km, and in the Austrian Alps about 2000 km. Active rock glaciers are a common feature of high mountain permafrost and due to their location near the lower boundary of permafrost, their mean annual surface temperature is close to melting conditions (Haeberli et al., 2006), which indicates their particular sensitivity to climate warming. Air temperature in the Alps has substantially increased during the past decades and climate warming is projected to become even more pronounced until the end of the 21th century. Increasing instability of slopes, landslides and floods, as well as alterations in the hydrological regime can be anticipated. Up to now, studies on the effects of active rock glaciers on hydrology and water chemistry of adjacent surface waters are still rare (e.g. Williams et al., 2006; Krainer et al., 2007; Thies et al., 2007; Baron et al., 2009). R...
... Author(s): Marchetto, A.; Rogora, M.; Boggero, A.; Musazzi, S.; Lami, A.; Lotter, A.; Tolotti... more ... Author(s): Marchetto, A.; Rogora, M.; Boggero, A.; Musazzi, S.; Lami, A.; Lotter, A.; Tolotti, M.; Thies, H.; Psenner, R.; Massaferro, J.; Barbieri, A. Affiliation FEM: Research and Innovation Centre. ... Citation: Marchetto, A., Rogora, M., Boggero, A., Musazzi, S., Lami, A., Lotter, A., et al. ...
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