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Per Persson. Foto.

Per Persson

Dekan

Per Persson. Foto.

Fourier-transform infrared spectroscopy (FTIRS), a new method to infer past changes in tree-line position and TOC using lake sediment

Författare

  • P. Rosen
  • Per Persson

Summary, in English

This study tests the hypothesis that Fourier-transform infrared spectroscopy (FTIRS) of lake sediments can be used to infer past changes in tree-line position and total organic carbon (TOC) content of lake water. A training set of 100 lakes from northern Sweden spanning a broad altitudinal and TOC gradient from 0.7 to 14.9 mg/l was used to assess whether vegetation zones and TOC can be modelled from FTIR spectra of surface sediments (0-1 cm) using principal component analysis (PCA) and partial least squares (PLS) regression. Preliminary results show that FTIRS of lake sediments can be used to reconstruct past changes in tree line and the TOC content of lake water, which is hardly surprising since FTIRS registers the properties of organic and minerogenic material derived from the water mass and the drainage area. The FTIRS model for TOC gives a root mean squared error (RMSECV) of calibration of 1.4 mg/l (10% of the gradient) assessed by internal cross-validation (CV) yielding an R-cv(2) of 0.64. This should be compared with a near-infrared spectroscopy (NIRS) and diatom transfer function for TOC from the same set of lakes, which have a R-cv(2) of 0.61 and 0.31, and RMSECV of 1.6 and 2.3 mg/l, respectively. The FTIRS-TOC model was applied to a Holocene sediment core from a tree-line lake and the results show similar trends as inferences from NIRS and pollen from the same core. Overall, the results indicate that changes in FTIR spectra from lake sediments reflect differences in catchment vegetation and TOC, and that FTIRS-models based on surface-sediment samples can be applied to sediment cores for retrospective analysis.

Publiceringsår

2006

Språk

Engelska

Sidor

913-923

Publikation/Tidskrift/Serie

Journal of Paleolimnology

Volym

35

Dokumenttyp

Artikel i tidskrift

Förlag

Springer

Ämne

  • Earth and Related Environmental Sciences

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 0921-2728