中文摘要：

软体动物为他们在他们的碳酸盐壳 paleoenvironmental 和 paleoclimatic 变化记录详细说明是众所周知的。在这研究，我们构造了 18 年的蓝颜色紧张和氧同位素侧面一 < 啜 class= “ a-plus-plus ” > 14 C 标明日期(广告 990 ??????????? 牔摩捡慮?????? 吗？？

英文摘要：

Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a14C dated （AD 990±40） fossil giant clam,Tridacna gigas, from Shidao Island, South China Sea. Theδ18O profile of theT. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with theδ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of theTridacna specimen was stable after the onset of sexual ma-turity. Spectral analysis of theδ18O and blue color intensity time series suggested that the El Ni？o-Southern Oscillation （ENSO） period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.