| Title | Ecological effects of multiple stressors on a deep lake (Lago Maggiore, Italy) integrating neo and palaeolimnological approaches |
| Abstract | To understand interactions of lake physical characteristics, trophic dynamics and climate in Lago Maggiore, we compare longterm limnological and meteorological monitoring data and results from sediment cores. We include analyses of nutrients, pigments, diatoms and cladoceran microfossils. Over the past decades, caloric content increased. Eutrophication from the 1960s to early 1980s was followed by oligotrophication. DDTs, PCBs and Hg showed high contamination in the '60s, compared to point source inputs in the '90s. Algal biomass was predicted by total pigments and some algal specific carotenoids. Following nutrient enrichment, Chydorus sphaericus, and total abundance of cladocerans changed inversely with trophic status. Fewer large Daphnia since the late '80s matched an increase in with subfossil Eubosmina mucro lengths. Both were explained by the 10-fold increase in Bythotrephes longimanus from 1987 to 1993, when an increase of its mean annual population density occurred during warmer winter and springs. Bythotrephes remained abundant and further increased during the following 10 years as water temperature increased. We conclude that warmer water affects food chains indirectly by changing habitat use and predator-prey interactions. Relative abundances of Daphnia and its peak population density in the warm year of the oligotrophic period (2003) were close to the record from the mesotrophic period in 1982, supporting the hypothesis that warming can produce a eutrophication-like signal. The study illustrates the complexity of biological responses to synchronous changes in multiple drivers (e.g., eutrophication, fish introduction, ban of fish harvesting, chemical pollution, and climate) and, despite this complexity, how Lago Maggiore responded to multiple stressors. |
| Source | Journal of limnology (Testo stamp.) 71 (1) |
| Keywords | Climate changeHuman impactPalaeolimnologyTime series |
| Journal | Journal of limnology (Testo stamp.) |
| Editor | Istituto per lo Studio degli Ecosistemi., Verbania Pallanza, Italia |
| Year | 2012 |
| Type | Articolo in rivista |
| DOI | 10.3274/JL12-71-1-01 |
| Authors | Guilizzoni, Piero; Levine, Suzanne N.; Manca, Marina; Marchetto, Aldo; Lami, Andrea; Ambrosetti, Walter; Brauer, Achim; Gerli, Stefano; Carrara, Elisabetta A.; Carrara, Elisabetta A.; Rolla, Angelo; Guzzella, Licia; VignatI, Davide A L |
| Text | 339326 2012 10.3274/JL12 71 1 01 Scopus 2 s2.0 82555205059 Climate change Human impact Palaeolimnology Time series Ecological effects of multiple stressors on a deep lake Lago Maggiore, Italy integrating neo and palaeolimnological approaches Guilizzoni, Piero; Levine, Suzanne N.; Manca, Marina; Marchetto, Aldo; Lami, Andrea; Ambrosetti, Walter; Brauer, Achim; Gerli, Stefano; Carrara, Elisabetta A.; Carrara, Elisabetta A.; Rolla, Angelo; Guzzella, Licia; VignatI, Davide A L Consiglio Nazionale delle Ricerche; University of Vermont; Deutsches GeoForschungsZentrum GFZ ; Consiglio Nazionale delle Ricerche; Bureau of Meteorology Australia To understand interactions of lake physical characteristics, trophic dynamics and climate in Lago Maggiore, we compare longterm limnological and meteorological monitoring data and results from sediment cores. We include analyses of nutrients, pigments, diatoms and cladoceran microfossils. Over the past decades, caloric content increased. Eutrophication from the 1960s to early 1980s was followed by oligotrophication. DDTs, PCBs and Hg showed high contamination in the 60s, compared to point source inputs in the 90s. Algal biomass was predicted by total pigments and some algal specific carotenoids. Following nutrient enrichment, Chydorus sphaericus, and total abundance of cladocerans changed inversely with trophic status. Fewer large Daphnia since the late 80s matched an increase in with subfossil Eubosmina mucro lengths. Both were explained by the 10 fold increase in Bythotrephes longimanus from 1987 to 1993, when an increase of its mean annual population density occurred during warmer winter and springs. Bythotrephes remained abundant and further increased during the following 10 years as water temperature increased. We conclude that warmer water affects food chains indirectly by changing habitat use and predator prey interactions. Relative abundances of Daphnia and its peak population density in the warm year of the oligotrophic period 2003 were close to the record from the mesotrophic period in 1982, supporting the hypothesis that warming can produce a eutrophication like signal. The study illustrates the complexity of biological responses to synchronous changes in multiple drivers e.g., eutrophication, fish introduction, ban of fish harvesting, chemical pollution, and climate and, despite this complexity, how Lago Maggiore responded to multiple stressors. 71 Published version http //www.scopus.com/record/display.url eid=2 s2.0 82555205059 origin=inward 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. liciamaria.guzzella GUZZELLA LICIA MARIA |
