青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis（Asano,1951）壳体δ18O值的季节变化

摘要

A successive 12-month study (June 2014 to May 2015) was conducted on the oxygen isotope composi-tion (δ18O) of living benthic foraminiferaAmmonia aomoriensis, from the intertidal flats of Qingdao Bay, Yellow Sea, China.δ18O values were measured in different diameter test groups, ranging from 200μm to 550μm, at 50μm intervals, from Rose Bengal stained specimens. The results showed that the fluctuant pattern ofδ18O was remarka-bly similar to the temperature and salinity changes, negative and positive, respectively. The variation inδ18O in livingA. aomoriensis was influenced by temperature and seawaterδ18O, and exhibited a seasonal pattern which showed a time-lag of about two months. This result implies that the large shell of A. aomoriensis reflects the envi-ronmentalδ18O conditions during the months when the chambers form, and probably record the oxygen isotopes, obtained by fractionation under actual calcification temperatures, over the whole life cycle.%近岸浅水底栖有孔虫是陆架海区古环境重建的重要手段,但是至今对其活体的研究非常缺乏。2014年6月至2015年5月对青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis进行了连续12个月的采样,用虎红染色以确认活体。对壳径范围在200~550μm的活体壳体,以每增加50μm壳径为一组,进行δ18O测试。结果显示,A. aomoriensis壳体δ18O的月平均值的季节变化趋势与温度和盐度一致,与温度反相关,与盐度正相关,即青岛湾A. aomoriensis壳体δ18O值受温度和海水δ18O的影响,其壳体δ18O值表现出了很好的季节性波动。但是A. aomoriensis壳体δ18O的变化滞后于所测温度和盐度约2个月,其记录的是虫体在生长周期内在真实钙化温度下分馏所得的δ18O值。