利用珊瑚生长率重建西沙海域罗马暖期中期海温变化

Sea Surface Temperature Variations during the Middle Rome Warm Period as Reconstructed by Poritescoralgrowth Rates in the Xisha Islands

珊瑚生长率是记录海水表层温度（SST）的一个重要代用指标。本文以南海中北部西沙永兴岛罗马暖期期间发育的3个澄黄滨珊瑚（Porites lutea）为材料,测量它们的骨骼生长率,并利用珊瑚骨骼生长率与SST的关系式定量重建海温年际变化序列。结果显示：3个滨珊瑚（生长于120-59BC、46BC-14AD和30BC-28AD期间）的平均生长率分别为0.88cm/a（变化于0.53~1.24cm/a之间）、0.90cm/a（变化于0.58~1.53cm/a之间）和1.12cm/a（变化于0.71~1.46cm/a之间）。据此重建同时段年平均SST,相应结果分别为26.7℃、26.8℃和27.3℃。2kaBP前后（120-59BC,46BC-28AD）西沙海域平均SST为26.9±0.4℃,低于现代（1981-2010AD）约0.7℃。

The skeletal growth rates of Porites corals are important indicators of ambient sea surface temperatures （SST）. Three Porites corals collected from Yongxing Island, Xisha Islands, dated to 120-59 BC, 46 BC-14 AD and 30 BC-28 AD respectively, were analyzed for skeletal growth rates to reconstruct the local SST variations in the Rome Warm Period. The mean values of their growth rates were 0.88 cm/a, 0.90 cm/a and 1.12 crn/a, ranging from 0.53-1.24 cm/a, 0.58-1.53 cm/a, and 0.71-1.46 cm/a, respectively. The reconstructed average annual SST were 26.7℃, 26.8℃ and 27.3℃ respectively. The average SST in the Xisha Islands was 26.93±0.41℃ during the Rome Warm Period （120-59BC, 46BC-28AD）, 0.7℃ lower than the mean temperature recored from 1981 to 2010AD.