Oxygen-isotope values of invertebrate cuticle preserved in lake sediments have been used in palaeoenvironmental reconstructions, generally with the assumption that fractionation of oxygen isotopes between cuticle and water (\(\upalpha_{\text{cuticle}-\text{H}_{2}\text{O}}\)) is independent of temperature. We cultured chironomid larvae in the laboratory with labelled oxygen-isotope water and across a range of closely controlled temperatures from 5 to 25 °C in order to test the hypothesis that fractionation of oxygen isotopes between chironomid head capsules and water (\(\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}\)) is independent of temperature. Results indicate that the hypothesis can be rejected, and that \(\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}\) decreases with increasing temperature. The scatter in the data suggests that further experiments are needed to verify the relationship. However, these results indicate that temperature-dependence of \(\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}\) should be considered when chironomid δ¹⁸O is used as a paleoenvironmental proxy, especially in cases where data from chironomids are combined with oxygen-isotope values from other materials for which fractionation is temperature dependent, such as calcite, in order to derive reconstructions of past water temperature.

湖泊沉积物中保存的无脊椎动物角质层的氧同位素值已用于古环境重建，通常假设角质层和水之间的氧同位素分馏（\（\ upalpha _ {\ text {cuticle}-\ text {H} _ { 2} \ text {O}} \））与温度无关。我们在实验室中用标记的氧同位素水在5至25°C的严密控制温度范围内培养了拟虫幼虫，以检验以下假设：即拟南芥头胶囊和水之间的氧同位素分馏（\（\ upalpha_ { \ text {chironomid}-\ text {H} _ {2} \ text {O}} \））与温度无关。结果表明该假设可以被拒绝，并且\（\ upalpha _ {\ text {chironomid}-\ text {H} _ {2} \ text {O}} \）随温度升高而降低。数据中的分散表明需要进一步的实验来验证这种关系。然而，这些结果表明的该温度依赖性\（\ upalpha _ {\文本{摇蚊} - \文本{H} _ {2} \文本{ö}} \）应当摇蚊δ被视为¹⁸ O时用作古环境的替代品，尤其是在将手性类动物的数据与分馏与温度相关的其他材料（如方解石）的氧同位素值结合起来以重建过去水温的情况下。