| Abstract | Deep lakes south of the Alps (DSL: Maggiore, Lugano, Como, Iseo and Garda) are characterised by varying trophic states and dissolved oxygen (DO) concentrations. Some of these lakes experience anoxic conditions in deep waters. We hypothesised that the increase in temperature and water-column stability observed in these lakes during recent decades influenced the deep-water DO concentration. In particular, we tested whether the thermal regime of the lakes and the depth of mixing affect oxygen replenishment during winter-spring turnover. To this aim, we analysed long-term trends and seasonal variability of oxygen levels in the DSL during 1992-2016. We included in our analysis the effects of environmental variables, such as winter air temperature and atmospheric modes of variability. Our results showed a recent decrease in the deep-water oxygen content in lakes Maggiore, Como and Garda and an increase of the extent of anoxic conditions in lakes Lugano and Iseo. Our results suggest that, beside cultural eutrophication, rising environmental pressures, such as global warming, can influence the future trends of the oxygen levels and ecological states of deep lakes. |
| Text | 399513 2018 10.1007/s10750 018 3623 y Scopus 2 s2.0 85046027880 ISI Web of Science WOS 000448578500002 Climate change Thermal regime Stratification Dissolved oxygen Eutrophication Climatic effects on vertical mixing and deep water oxygen content in the subalpine lakes in Italy Rogora M.; Buzzi F.; Dresti C.; Leoni B.; Lepori F.; Mosello R.; Patelli M.; Salmaso N. CNR Institute of Ecosystem Study, L.go Tonolli 50, Verbania Pallanza, 28922, , Italy; UO CRLMBAS, ARPA Lombardia, Via I Maggio 21/b, Oggiono, Lecco, 23848, , Italy; Department of Earth and Environmental Sciences, University of Milano Bicocca, Piazza della Scienza 1, Milan, 20126, , Italy; University of Applied Sciences and Arts of Southern Switzerland SUPSI , Via Trevano 72, Canobbio, 6952, , Switzerland; Research and Innovation Centre, Fondazione Edmund Mach FEM , Via E. Mach 1, San Michele all Adige, 38010, , Italy Deep lakes south of the Alps DSL Maggiore, Lugano, Como, Iseo and Garda are characterised by varying trophic states and dissolved oxygen DO concentrations. Some of these lakes experience anoxic conditions in deep waters. We hypothesised that the increase in temperature and water column stability observed in these lakes during recent decades influenced the deep water DO concentration. In particular, we tested whether the thermal regime of the lakes and the depth of mixing affect oxygen replenishment during winter spring turnover. To this aim, we analysed long term trends and seasonal variability of oxygen levels in the DSL during 1992 2016. We included in our analysis the effects of environmental variables, such as winter air temperature and atmospheric modes of variability. Our results showed a recent decrease in the deep water oxygen content in lakes Maggiore, Como and Garda and an increase of the extent of anoxic conditions in lakes Lugano and Iseo. Our results suggest that, beside cultural eutrophication, rising environmental pressures, such as global warming, can influence the future trends of the oxygen levels and ecological states of deep lakes. 824 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 85046027880 partnerID=q2rCbXpz Articolo 2018_Hydrobiologia_824_33_50.pdf Articolo in rivista Kluwer Academic Publishers 0018 8158 Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia. The Hague. Print Hydrobiologia Dordrecht The Hague. Print Hydrobiologia Boston The Hague. Print Hydrobiologia London The Hague. Print claudia.dresti DRESTI CLAUDIA rosario.mosello MOSELLO ROSARIO michela.rogora ROGORA MICHELA |
