Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Using diatoms to assess geographical patterns of change in high-latitude European lakes from pre-industrial time to present day |
| Abstract | Baseline and historical environmental data are sparse in high-altitude regions. Diatom assemblages preserved in lake sediment records can, however, provide proxy data of past environmental and biological conditions. Sediment cores were retrieved from 209 high altitude lakes from 11 countries in Europe. Diatoms were extracted and counted from surface-sediment samples and sediments representing pre-industrial conditions. Regional changes in diatom assemblages covering at least the last c. 150 years are discussed and quantified using ordination techniques and dissimilarity indices. Distinct changes in diatom composition are identified and regional patterns highlighted, with two lake regions showing particularly large changes in diatom composition (Central Swiss Alps and the Pyrenees). Several driving mechanisms that might have caused the changes in the diatom community are discussed. Pre-industrial and present-day lake-water pH are inferred from the diatom assemblages and their prediction accuracy compared to contemporary water-chemistry measurements for each lake. Regional pH changes are minimal with no lake region exceeding 0.27 pH units of change in the period covering the last c. 150 years. The majority of lakes studied show an increase in planktonic diatom species over the period covering the past c. 150 years. We hypothesise that changes in the ratio of planktonic to non-planktonic diatoms within the study lake-regions are related to changes in climate and to associated changes in nutrients, ice-cover and erosion caused by climate warming. |
| Source | Aquatic sciences (Print. ed.) 67, pp. 224–236 |
| Journal | Aquatic sciences (Print. ed.) |
| Editor | Birkhäuser, Basel, Svizzera |
| Year | 2005 |
| Type | Articolo in rivista |
| DOI | 10.1007/s00027-004-0745-2 |
| Authors | Clarke G.(1), Kernan M.(1), Marchetto A.(2), Sorvari S.(3), Catalan J.(4) |
| Text | 52866 2005 10.1007/s00027 004 0745 2 PUMA http //puma.isti.cnr.it/linkres.php resource=cnr.ise/cnr.ise/2005 A0 049 Using diatoms to assess geographical patterns of change in high latitude European lakes from pre industrial time to present day Clarke G. 1 , Kernan M. 1 , Marchetto A. 2 , Sorvari S. 3 , Catalan J. 4 1 Environmental Change Research Centre, Department of Geography, University College London, 26 Bedford Way, London WC1H 0AP, United Kingdom 2 CNR Institute for Ecosystem Study, Largo Tonolli 50, 28922 Verbania, Pallanza, Italy 3 ECRU, Department of Ecology and Systematics, University of Helsinki FIN 00014, Finland 4 Department of Ecology, University of Barcelona, Diagonal 645, Barcelona 08028, Spain Baseline and historical environmental data are sparse in high altitude regions. Diatom assemblages preserved in lake sediment records can, however, provide proxy data of past environmental and biological conditions. Sediment cores were retrieved from 209 high altitude lakes from 11 countries in Europe. Diatoms were extracted and counted from surface sediment samples and sediments representing pre industrial conditions. Regional changes in diatom assemblages covering at least the last c. 150 years are discussed and quantified using ordination techniques and dissimilarity indices. Distinct changes in diatom composition are identified and regional patterns highlighted, with two lake regions showing particularly large changes in diatom composition Central Swiss Alps and the Pyrenees . Several driving mechanisms that might have caused the changes in the diatom community are discussed. Pre industrial and present day lake water pH are inferred from the diatom assemblages and their prediction accuracy compared to contemporary water chemistry measurements for each lake. Regional pH changes are minimal with no lake region exceeding 0.27 pH units of change in the period covering the last c. 150 years. The majority of lakes studied show an increase in planktonic diatom species over the period covering the past c. 150 years. We hypothesise that changes in the ratio of planktonic to non planktonic diatoms within the study lake regions are related to changes in climate and to associated changes in nutrients, ice cover and erosion caused by climate warming. 67 articolo pubblicato 02_AqSci_2005 1.pdf Articolo in rivista Birkhauser 1015 1621 Aquatic sciences Print. ed. Aquatic sciences Print. ed. Aquat. sci. Print. ed. Aquatic sciences. Print. ed. aldo.marchetto MARCHETTO ALDO TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |