TY - JOUR

T1 - Oxygen isotope fluctuations in a modern North Sea oyster (Crassostrea gigas) compared with annual variations in seawater temperature

T2 - implications for palaeoclimate studies.

AU - Ullmann, Clemens Vinzenz

AU - Wiechert, Uwe

AU - Korte, Christoph

PY - 2010

Y1 - 2010

N2 - A total of 181 oxygen isotope values from sequential samples of the left shell of a modern Pacific Oyster (Crassostrea gigas) that lived on a sub-tidal oyster bank in the List Basin (North Sea, Germany) shows periodically varying values between + 1.3‰ and -2.5‰. In order to test whether these d18O fluctuations reflect seawater temperature changes, the isotope values of the shell were compared to actual seawater temperature variations from the region. C. gigas serves as an excellent proxy for temperature of palaeoseawater and the results show that the examined oyster precipitated its shell in d18O equilibrium with the ambient seawater. A cessation of the oyster shell calcification starts at water temperatures below 6 °C, at lower temperatures than previously thought for Crassostrea. For palaeoclimate investigations the termination of shell production is important because the lowest temperatures might not be represented in the shell. Higher water temperatures are therefore potentially over-represented in time spans when the shell grows faster and mean oxygen isotope values may potentially bias the mean seawater temperatures of annual variations towards higher temperatures.

AB - A total of 181 oxygen isotope values from sequential samples of the left shell of a modern Pacific Oyster (Crassostrea gigas) that lived on a sub-tidal oyster bank in the List Basin (North Sea, Germany) shows periodically varying values between + 1.3‰ and -2.5‰. In order to test whether these d18O fluctuations reflect seawater temperature changes, the isotope values of the shell were compared to actual seawater temperature variations from the region. C. gigas serves as an excellent proxy for temperature of palaeoseawater and the results show that the examined oyster precipitated its shell in d18O equilibrium with the ambient seawater. A cessation of the oyster shell calcification starts at water temperatures below 6 °C, at lower temperatures than previously thought for Crassostrea. For palaeoclimate investigations the termination of shell production is important because the lowest temperatures might not be represented in the shell. Higher water temperatures are therefore potentially over-represented in time spans when the shell grows faster and mean oxygen isotope values may potentially bias the mean seawater temperatures of annual variations towards higher temperatures.

U2 - 10.1016/j.chemgeo.2010.07.019

DO - 10.1016/j.chemgeo.2010.07.019

M3 - Journal article

VL - 277

SP - 160

EP - 166

JO - Chemical Geology

JF - Chemical Geology

SN - 0009-2541

IS - 1-2

ER -