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Sensitivity of biogenic silica oxygen isotopes to changes in surface water temperature and palaeoclimatology
Author(s) -
Moschen Robert,
Lücke Andreas,
Schleser Gerhard H.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl022167
Subject(s) - isotopes of oxygen , fractionation , diatom , paleoclimatology , isotope , biogenic silica , oxygen , equilibrium fractionation , environmental chemistry , stable isotope ratio , environmental science , isotope fractionation , chemistry , geology , oceanography , climate change , chromatography , quantum mechanics , physics , organic chemistry , nuclear chemistry
Oxygen isotope ratios of biogenic silica derived from planktonic diatoms living in the pelagial of a freshwater lake are used to determine the temperature effect on the isotope fractionation between water and biogenic silica under ecosystem conditions. Our data show a deterministic relation between seasonally changing water temperatures (4°C–22°C) and the oxygen isotope fractionation during valve formation. The temperature dependent fractionation appears to be independent of diatom cell sizes indicating a mere physical control of this process. The isotopic change induced per degree centigrade, the temperature coefficient, amounts to a value of −0.2‰/°C. This implies that previous studies have overestimated the temperature relationship of this proxy by using coefficients of up to −0.5‰/°C for climate reconstructions.