作　　者： ; ; ; ; ;

机构地区： 中国科学院广州能源研究所

出　　处： 《海洋与湖沼》 2014年第6期1202-1217,共16页

摘　　要： 本研究采用色谱质谱(GC-MS)和色谱-同位素质谱(GC-IRMS)方法,对珠江口盆地Site4B沉积物中脂肪醇分子化合物分布以及单体碳同位素组成进行了研究。结果表明:长链脂肪醇碳优势指数(CPIC26—34:9.41—24.56)、平均碳链长度(ACLC26—34:28.85—29.99)以及n C26—n C30脂肪醇平均碳同位素组成(?29.13‰±0.87‰、?32.98‰±1.28‰和?32.73‰±1.61‰)均揭示了n C26—n C34脂肪醇属于陆源高等植物来源,n C16—n C20和n C24脂肪醇较正的碳同位素组成反映了化合物的海洋细菌来源,而n C22脂肪醇偏负的碳同位素特征(平均?33.26‰±1.51‰)反映了化学自养细菌来源。Site4B沉积物中的陆源输入主要来自南海周边河流,从12.7ka BP至今的沉积时期(0—80cm,文中深度均为埋深)和末次冰盛期(102—120cm),其陆源输入主要来自台湾岛河流,而在19.3—12.7ka BP沉积时期(80—102cm)和更新世沉积时期(120—300cm),台湾岛、吕宋岛和珠江口河流的陆源贡献普遍较低。Site4B沉积物中的海洋生产力主要来自海洋微生物输入的贡献,并主要受到海水温差影响;其中在35—150cm层位,海洋输入和南海暖流的强弱带来的海水温度的高低有关,而在150—300cm层位,则主要和冰期-间冰期的冷暖气候带来的海水温差有关。 Distribution and carbon isotope composition of alcohol compounds in Site4 B sediment in the Zhujiang(Pearl) River Mouth Basin are analyzed by GC-MS(gas chromatography-mass spectrometry) and GC-IRMS(gas chromatography-isotope ratio monitoring mass spectrometry). The results show that the values of carbon preference index(9.41—24.56), average chain length(28.85—29.99), and the average carbon isotope of n C26, n C28, and n C30 aliphatic alcohol(?29.13‰±0.87‰, ?32.98‰±1.28‰, and ?32.73‰±1.61‰, respectively) indicate a source of terrestrial higher plants for n C26—n C34 aliphatic alcohols. The carbon isotope compositions of n C16—n C20 and n C24 aliphatic alcohols were substantially enriched in 13 C relative to n C26—n C34 aliphatic alcohols, suggesting potential source of marine microbe other than terrestrial higher plants; the negative isotope composition of n C22 aliphatic alcohol(?33.26‰±1.51‰) might indicate a potential source of the chemical autotrophic bacteria. The terrigenous inputs in the sediments are dominated by adjacent rivers. Contribution of the Taiwan Island rivers was significant since 12.7ka BP(0—80cm) and in the Last Glacial Maximum(102—120cm), whereas those of the Taiwan Island, Luzon Arc, and Zhujiang River estuary rivers were generally not significant from 19.3—12.7ka BP(80—102cm) and in the Pleistocene(120—300cm). The marine productivity was contributed by marine microbe that effected heavily by fluctuation in seawater temperature, of which at depths of 35—150cm marine-sourced alcohols was related to the seawater temperature fluctuation caused by the change in the strength of the South China Sea warm current, whereas at depths of 150—300cm, it was directly related to the seawater temperature variation resulted from cold-warm climate alternation between glacial and interglacial periods.

关 键 词： 珠江口盆地 脂肪醇 碳同位素 陆源输入 海洋生产力

领　　域： [天文地球] [天文地球]