| Abstract | Sediment accumulation rate (SAR) is an important physical parameter in all lakes and increases have been observed in many over the last c.100 years. This has been ascribed to changes in land-use and land-management causing accelerated catchment soil erosion and an increase in autochthonous organic matter production. The EU Water Framework Directive requires that assessment of biological, hydromorphological and chemical elements of water quality should be based on the degree to which present day conditions deviate from those expected in the absence of significant anthropogenic influence, termed reference conditions. Currently however, the reference condition for sediment accumulation rate for lakes of different types is undefined. To improve our understanding of the controls on SARs we compiled SAR and lake typology data for 207 European lakes derived from (210)Pb dated cores to assess how rates have changed through time (in 25 year classes) both overall and for lakes of different types. Seventy-one percent of these sediment cores showed surface SARs higher than "basal" (mainly nineteenth century) rates, 11% showed no change while 18% showed a decline. Lakes were then classified into lake-types using four variables: alkalinity (3 classes), altitude (3 classes), maximum depth (2 classes) and lake area (2 classes). This generated a possible 36 lake classes of which 25 were represented in the dataset. Nine lake-types contained > 10 lakes. Little change in SAR occurred prior to 1900 and most increases occurred in more recent periods, in particular 1950-1975 and post-1975. This indicates a general acceleration in SAR in European lakes during the second half of the twentieth century. Reference SARs were estimated for six lake-types with the highest number of sites. European mountain lakes had the lowest reference SAR (0.005 +/- A 0.003 g cm(-2) yr(-1)) while lowland, high alkalinity sites had the highest (0.03-0.04 g cm(-2) yr(-1)). SARs for other lake-types ranged between 0.012 and 0.024 g cm(-2) yr(-1). Using the mountain lake-type as an example, the 1850 reference SAR appears to show good agreement with available data for lakes beyond Europe indicating these values may be more broadly applicable. Contemporary SARs in lakes of all classes showed exceedence over their defined reference SAR. This may be partly due to diagenetic processes. Greatest exceedences were found in shallow, low altitude lakes and these are considered to be the ones under the greatest threat from continued elevation of SAR. It is considered that climate change may play a progressively more important role in driving SAR in the future. |
| Authors | Rose, NL (Rose, Neil L.)[ 1 ] ; Morley, D (Morley, David)[ 1 ] ; Appleby, PG (Appleby, Peter G.)[ 2 ] ; Battarbee, RW (Battarbee, Richard W.)[ 1 ] ; Alliksaar, T (Alliksaar, Tiiu)[ 3 ] ; Guilizzoni, P (Guilizzoni, Piero)[ 4 ] ; Jeppesen, E (Jeppesen, Erik)[ 5 ] ; Korhola, A (Korhola, Atte)[ 6 ] ; Punning, JM (Punning, Jaan-Mati)[ 7 ] |
| Text | 203825 2011 10.1007/s10933 010 9424 6 ISI Web of Science WOS 000290043900005 Accumulation rate Europe Reference conditions Lake sediments Water Framework Directive Sediment accumulation rates in European lakes since AD 1850 trends, reference conditions and exceedence Rose, NL Rose, Neil L. 1 ; Morley, D Morley, David 1 ; Appleby, PG Appleby, Peter G. 2 ; Battarbee, RW Battarbee, Richard W. 1 ; Alliksaar, T Alliksaar, Tiiu 3 ; Guilizzoni, P Guilizzoni, Piero 4 ; Jeppesen, E Jeppesen, Erik 5 ; Korhola, A Korhola, Atte 6 ; Punning, JM Punning, Jaan Mati 7 1 UCL, Environm Change Res Ctr, London WC1E 6BT, England 2 Univ Liverpool, Dept Math Sci, Liverpool L69 3BX, Merseyside, England 3 Tallinn Univ Technol, Inst Geol, EE 19086 Tallinn, Estonia 4 CNR, ISE, Verbania, Italy 5 Univ Aarhus, Natl Environm Res Inst, Dept Freshwater Ecol, DK 8600 Silkeborg, Denmark 6 Univ Helsinki, Environm Change Res Unit, Dept Biol Environm Sci, Helsinki, Finland 7 Tallinn Univ, Inst Ecol, EE 10120 Tallinn, Estonia Sediment accumulation rate SAR is an important physical parameter in all lakes and increases have been observed in many over the last c.100 years. This has been ascribed to changes in land use and land management causing accelerated catchment soil erosion and an increase in autochthonous organic matter production. The EU Water Framework Directive requires that assessment of biological, hydromorphological and chemical elements of water quality should be based on the degree to which present day conditions deviate from those expected in the absence of significant anthropogenic influence, termed reference conditions. Currently however, the reference condition for sediment accumulation rate for lakes of different types is undefined. To improve our understanding of the controls on SARs we compiled SAR and lake typology data for 207 European lakes derived from 210 Pb dated cores to assess how rates have changed through time in 25 year classes both overall and for lakes of different types. Seventy one percent of these sediment cores showed surface SARs higher than basal mainly nineteenth century rates, 11% showed no change while 18% showed a decline. Lakes were then classified into lake types using four variables alkalinity 3 classes , altitude 3 classes , maximum depth 2 classes and lake area 2 classes . This generated a possible 36 lake classes of which 25 were represented in the dataset. Nine lake types contained > 10 lakes. Little change in SAR occurred prior to 1900 and most increases occurred in more recent periods, in particular 1950 1975 and post 1975. This indicates a general acceleration in SAR in European lakes during the second half of the twentieth century. Reference SARs were estimated for six lake types with the highest number of sites. European mountain lakes had the lowest reference SAR 0.005 / A 0.003 g cm 2 yr 1 while lowland, high alkalinity sites had the highest 0.03 0.04 g cm 2 yr 1 . SARs for other lake types ranged between 0.012 and 0.024 g cm 2 yr 1 . Using the mountain lake type as an example, the 1850 reference SAR appears to show good agreement with available data for lakes beyond Europe indicating these values may be more broadly applicable. Contemporary SARs in lakes of all classes showed exceedence over their defined reference SAR. This may be partly due to diagenetic processes. Greatest exceedences were found in shallow, low altitude lakes and these are considered to be the ones under the greatest threat from continued elevation of SAR. It is considered that climate change may play a progressively more important role in driving SAR in the future. 45 ID_PUMA r.ise/2011 A0 035. ID Modulo Commessa 4007 TA.P02.014.002 094 Modificazioni strutturali e funzionali degli ecosistemi acquatici anche in relazione al loro bacino imbrifero, in risposta ai cambiamenti meteo climatici e, in particolare, in risposta alle deposizioni atmosferiche Sediment accumulation rates in European lakes since AD 1850 Sediment_accumulation_rates_in_European_lakes_since_AD_1850.pdf Articolo in rivista Kluwer Academic 0921 2728 Journal of paleolimnology Journal of paleolimnology J. paleolimnol. piero.guilizzoni GUILIZZONI PIERO |
