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硅藻氧同位素已日益成为重要的定量古气候研究手段,但在我国仍处探索阶段.选取东北四龙湾玛珥湖进行了为期2a的湖泊监测、样品收集和现代硅藻氧同位素研究,为该玛珥湖定量化古气候记录研究奠定基础.逐步氟化条件实验表明,我们已完全具备和掌握了硅藻氧同位素研究的实验设备和技术方法.现代硅藻样品的氧同位素结果显示,在3.6～24℃的水体温度区间硅藻氧同位素与生长温度存在着线性分馏关系,分馏梯度为–0.185‰/℃～–0.238‰/℃,与近年来不同水体、不同地区、不同种属以及实验室培养硅藻的研究结果有良好的一致性,揭示了硅藻壳体氧同位素的分馏效应主要受控于生长温度.四龙湾表层和底层沉积硅藻氧同位素的对比研究发现,二者存在一定的差别,可能与不同深度沉积过程的差异以及硅藻来源差异有关.
Diatom oxygen isotope has increasingly become an important quantitative paleoclimate research method, but it is still in the exploratory stage in our country.Selecting the lacustrine 2a monitoring, sample collection and modern diatom oxygen isotope study in the Ma Long Lake, The research on the quantitative paleoclimate records of Maar Lake laid the foundation for the progress of fluorination experiments.It is shown that we have fully equipped and mastered the experimental equipment and technical methods for the study of oxygen isotopes of diatoms.According to the oxygen isotope results of modern diatom samples, There is a linear fractionation relationship between the oxygen isotopes of diatoms and the growth temperature in the temperature range of ~ 24 ℃. The fractional gradient is -0.185 ‰ / ℃ ~ -0.238 ‰ / ℃, which is similar to that in different water bodies, different regions, different species and laboratories in recent years The results of the cultivation of diatoms are in good agreement, revealing that the fractional effect of oxygen isotopes in the diatom shell is mainly controlled by the growth temperature. A comparative study of the oxygen and oxygen isotopes of diatoms deposited in the surface and bottom sediments of Four Longwan found that both The differences may be related to the differences of depositional processes at different depths and the differences in the source of diatoms.