利用稳定碳同位素分析技术研究了南沙渚碧礁生态系食物网主要生物类群之间的营养关系 .结果表明 ,生物的稳定碳同位素组成与其营养来源有密切关系 .浮游植物的δ13C为 - 1 8.3‰ ,与其所处海域的环境条件一致 .浮游动物的δ13C值变化较大 ,范围为 - 2 0 .4‰～ - 1 0 .9‰ ,表明可能存在浮游植物和碎屑两种营养来源 .珊瑚和砗磲的碳同位素组成 (- 1 7‰～ - 1 5‰ )与浮游动物相差较大 ,暗示共生虫黄藻可能在这些珊瑚的营养来源中起重要作用 .底栖海参 (- 9.6‰ )和蜘蛛螺 (- 1 2 .5‰ )的碳同位素组成与它们沉积物食性的营养特征吻合 .鱼类的δ13C值变化范围较大(- 1 7.7‰～ - 1 0 .9‰ ) ,未表现出随营养级升高而增大的趋势 ,说明影响鱼类碳同位素组成的因素比较复杂Trophic relationships among various organisms from Zhubi coral reef ecosystem in Nansha Islands were studied by stable carbon isotope technique. The results showed that δ 13 C of organisms showed a close relationship with their trophic status. δ 13 C of phytoplankton was -18.3‰ , which is consistent with the tropical marine environment. The great variation in δ 13 C of zooplankton(-20.4‰ ～ -10.9‰) was suggested that there may exist two trophic sources -- phytoplankton and detritus. δ 13 C of coral tissue and tridacnids were similar (-17‰ ～ -15‰ ) and showed great difference with zooplankton, suggesting that symbiotic zooxanthellae may play an important role in their nutrition source. Carbon isotope ratios of benthic sea cucumber Bohadshia argus and gastropod Lambis lambis were consistent with their sediment-feeding nutrition characteristics. Great variation and no obvious increase trend with trophic levels of fish δ 13 C values indicated that complex factors controlled their carbon isotope composition.国家重点科技专项专题 (97 92 6 0 2 0 2 ) ;; 厦门大学校级自选课题 (2 0 0 0 5 0 0 2
