Recursos Naturales >
Centro de Estudios Avanzados de Blanes (CEAB) >
(CEAB) Artículos >
Closed Access item Climate variability and ecosystem dynamics at remote alpine and arctic lakes: the last 200 years
Grytnes, J. A.
Birks, H. J. B.
|Keywords:||Instrumental records, Pigments, Remote mountain lakes, Palaeolimnology, Climate change, Diatoms, Cladocera, Chironomids, Chrysophytes|
|Citation:||Journal of Paleolimnology 28 : 161-179 (2002)|
|Abstract:||This paper compares the palaeolimnological evidence for climate change over the last 200 years with instrumental
climate data for the same period at seven European remote mountain lakes. The sites are Øvre Neådalsvatn (Norway),
Saanajärvi (Finland), Gossenköllesee (Austria), Hagelseewli (Switzerland), Jezero v Ledvici (Slovenia),
Estany Redó (Spain, Pyrenees), and NiÓné Terianske Pleso (Slovakia). We used multiple regression analysis to transfer
homogenised lowland air temperature records to each of the sites, and these reconstructions were validated using
data from on-site automatic weather stations. These data showed that mean annual temperature has varied over the
last 200 years at each site by between 1 and 2 °C, typical of the high frequency variability found throughout the
Holocene, and appropriate, therefore, to test the sensitivity of the various proxy methods used. Sediment cores from
each site were radiometrically dated using 210Pb, 137Cs and 241Am and analysed for loss-on-ignition, C, N, S, pigments,
diatoms, chrysophytes, Cladocera and chironomids. Comparisons between the proxy data and the instrumental
data were based on linear regression analysis with the proxy data treated as response variables and the
instrumental data (after smoothing using LOESS regressions) as predictor variables. The results showed few clear
or consistent patterns with generally low or very low r2 values. Highest values were found when the data were
compared after smoothing using a broad span, indicating that some of the proxy data were capturing climate variability
but only at a relatively coarse time resolution. Probable reasons for the weak performance of the methods
used include inaccurate dating, especially for earlier time periods, the influence of confounding forcing factors at some sites e.g., air pollution, earthquakes, and the insensitivity of some methods to low amplitude climate forcing.
Nevertheless, there were trends in some proxy records at a number of sites that had a relatively unambiguous correspondence
with the instrumental climate records. These included organic matter and associated variables (C and
N) and planktonic diatom assemblages at the majority of sites and chrysophytes and chironomids at a few sites.
Overall for longer term studies of the Holocene, these results indicate the need to be cautious in the interpretation
of proxy records, the importance of proxy method validation, the continuing need to use reinforcing multi-proxy
approaches, and the need for careful site and method selection.|
|Description:||19 páginas, 11 tablas, 4 figuras.|
|Publisher version (URL):||http://dx.doi.org/161-179, DOI: 10.1023/A:1020384204940|
|E-ISSNmetadata.dc.identifier.doi = DOI:||1573-0417|
|Appears in Collections:||(CEAB) Artículos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.