| Abstract | 1. We carried out a coordinated survey of mountain lakes covering the main ranges across Europe (including Greenland), sampling 379 lakes above the local tree line in 2000. The objectives were to identify the main sources of chemical variability in mountain lakes, define a chemical lassification of lakes, and develop tools to extrapolate our results to regional lake populations through an empirical regionalisation or upscaling of chemical properties. 2. We investigated the main causes of chemical variability using factor analysis (FA) and empirical relationships between chemistry and several environmental variables. Weathering, sea salt inputs, atmospheric deposition of N and S, and biological activity in soils of the catchment were identified as the major drivers of lake chemistry. 3. We tested discriminant analysis (DA) to predict the lake chemistry. It was possible to use the lithology of the catchments to predict the range of Ca2+ and SO(4)2- into which a lake of unknown chemistry will decrease. Lakes with lower SO(4)2- concentrations have little geologically derived S, and better reflect the variations in atmospheric S loading. The influence of marine aerosols on lakewater chemistry could also be predicted from the minimum distance to the sea and altitude of the lakes. 4. The most remarkable result of FA was to reveal a factor correlated to DOC (positively) and NO3- (negatively). This inverse relationship might be the result either of independent processes active in the catchment soils and acting in an opposite sense, or a direct interaction, e.g. limitation of denitrification by DOC availability. Such a relationship has been reported in the recent literature in many sites and at all scales, appearing to be a global pattern that could reflect the link between the C and N cycles. 5. The concentration of NO3- is determined by both atmospheric N deposition and the processing capacity of the catchments (i.e. N uptake by plants and soil microbes). The fraction of the variability in NO3- because of atmospheric deposition is captured by an independent factor in the FA. This is the only factor showing a clear pattern when mapped over Europe, indicating lower N deposition in the northernmost areas. 6. A classification has been derived which takes into account all the major chemical features of the mountain lakes in Europe. FA provided the criteria to establish the most important factors influencing lake water chemistry, define classes within them, and classify the surveyed lakes into each class. DA can be used as a tool to scale up the classification to unsurveyed lakes, regarding sensitivity to acidification, marine influence and sources of S. |
| Authors | Camarero L.(1), Rogora M., Mosello R., Anderson N.J.(2), Barbieri A.(3), Botev I.(4), Kernan M.(5), Kopacek J.(6), Korhola A.(7), Lotter A.F.(8), Muri G.(9), Postolache C.(10), Stuchlik E.(11), Thies H.(12), Wright R.F.(13) |
| Text | 53112 2009 10.1111/j.1365 2427.2009.02296.x chemical classification lakewater chemistry mountain lakes regionalisation upscaling Regionalisation of chemical variability in European mountain lakes Camarero L. 1 , Rogora M., Mosello R., Anderson N.J. 2 , Barbieri A. 3 , Botev I. 4 , Kernan M. 5 , Kopacek J. 6 , Korhola A. 7 , Lotter A.F. 8 , Muri G. 9 , Postolache C. 10 , Stuchlik E. 11 , Thies H. 12 , Wright R.F. 13 1 CSIC, Ctr Estudis Avancats Blanes, Limnol. Observ. Pyrenees, 17300 Blanes, Spain; 2 Copenhagen GeoCtr, Geol. Survey Denmark Greenland GEUS, Copenhagen, Denmark; 3 SPAA, Lab. Studi Ambientali, Paradiso Lugano, Switzerland; 4 BAS, Inst. Zool., Sofia, Bulgaria; 5 UCL, Dept. Geog., Environm. Change Res. Ctr., London, England; 6 Hydrobiol. Inst. AS CR, Ceske Budejovice, Czech Republic; 7 Univ. Helsinki, Dept. Biol. and Environm. Sci., ECRU, Helsinki, Finland; 8 Univ. Utrecht, Palaeobot and Palynol. Lab., 3584 CS Utrecht, Netherlands; 9 Natl. Inst. Biol., Ljubljana, Slovenia; 10 Univ. Bucharest, Dept. Syst. Ecol., Bucharest, Romania; 11 Charles Univ. Prague, Inst. Environm. Studies, Hydrobiol. Stn. Velky Palenec, Blatna, Czech Republic; 12 Innsbruck Univ., Inst. Ecol., 6020 Innsbruck, Austria; 14 Norwegian Inst. Water. Res., Oslo, Norway 1. We carried out a coordinated survey of mountain lakes covering the main ranges across Europe including Greenland , sampling 379 lakes above the local tree line in 2000. The objectives were to identify the main sources of chemical variability in mountain lakes, define a chemical lassification of lakes, and develop tools to extrapolate our results to regional lake populations through an empirical regionalisation or upscaling of chemical properties. 2. We investigated the main causes of chemical variability using factor analysis FA and empirical relationships between chemistry and several environmental variables. Weathering, sea salt inputs, atmospheric deposition of N and S, and biological activity in soils of the catchment were identified as the major drivers of lake chemistry. 3. We tested discriminant analysis DA to predict the lake chemistry. It was possible to use the lithology of the catchments to predict the range of Ca2 and SO 4 2 into which a lake of unknown chemistry will decrease. Lakes with lower SO 4 2 concentrations have little geologically derived S, and better reflect the variations in atmospheric S loading. The influence of marine aerosols on lakewater chemistry could also be predicted from the minimum distance to the sea and altitude of the lakes. 4. The most remarkable result of FA was to reveal a factor correlated to DOC positively and NO3 negatively . This inverse relationship might be the result either of independent processes active in the catchment soils and acting in an opposite sense, or a direct interaction, e.g. limitation of denitrification by DOC availability. Such a relationship has been reported in the recent literature in many sites and at all scales, appearing to be a global pattern that could reflect the link between the C and N cycles. 5. The concentration of NO3 is determined by both atmospheric N deposition and the processing capacity of the catchments i.e. N uptake by plants and soil microbes . The fraction of the variability in NO3 because of atmospheric deposition is captured by an independent factor in the FA. This is the only factor showing a clear pattern when mapped over Europe, indicating lower N deposition in the northernmost areas. 6. A classification has been derived which takes into account all the major chemical features of the mountain lakes in Europe. FA provided the criteria to establish the most important factors influencing lake water chemistry, define classes within them, and classify the surveyed lakes into each class. DA can be used as a tool to scale up the classification to unsurveyed lakes, regarding sensitivity to acidification, marine influence and sources of S. 54 Published version Articolo in rivista Blackwell Scientific Publications. 0046 5070 Freshwater biology Print Freshwater biology Print Freshw. biol. Print michela.rogora ROGORA MICHELA rosario.mosello MOSELLO ROSARIO TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |
