Crespin J., Sylvestre Florence, Alexandre A., Sonzogni C., Pailles C., Perga M. E. (2010). Re-examination of the temperature-dependent relationship between delta O-18 (diatoms) and delta O-18 (lake water) and implications for paleoclimate inferences. Journal of Paleolimnology, 44 (2), p. 547-557. ISSN 0921-2728.
Titre du document
Re-examination of the temperature-dependent relationship between delta O-18 (diatoms) and delta O-18 (lake water) and implications for paleoclimate inferences
Crespin J., Sylvestre Florence, Alexandre A., Sonzogni C., Pailles C., Perga M. E.
Source
Journal of Paleolimnology, 2010,
44 (2), p. 547-557 ISSN 0921-2728
The oxygen isotope composition (delta O-18) of diatoms is commonly used for paleoclimate reconstruction. There is, however, no consensus regarding the equilibrium isotopic fractionation factor between diatom silica and the water in which it is precipitated. We re-examined the temperature-dependent relationship between delta O-18(diatoms) and delta O-18(lake water) from Lake Annecy (France). A temperature coefficient of -0.16aEuro degrees/A degrees C (R (2) = 0.51) was determined, supporting findings from previous calibration studies. However, regression lines obtained from different calibration studies, though displaying similar slopes, were shifted. In this manuscript, we propose that several factors, including selected variables (temperature, delta O-18(lake water)), analytical techniques, the impact of diagenetic processes and biological effects, may influence the silica-water fractionation factor for diatom silica. The similar magnitude of the diatom-temperature coefficients determined across studies is promising, supporting its use as a valuable tool for interpreting variations in delta O-18 values from fossil lacustrine diatoms in temperate lakes. With respect to paleoclimatic applications, the temperature-dependent relationship yielded uncertainties of +/- 3A degrees C on reconstructed temperatures and +/- 0.5aEuro degrees on delta O-18(lake water).
