论文部分内容阅读
以1998,2000,2005年所取的珠江水体悬浮物为研究对象,对其碳同位素组成(14C,13C)及表观年龄(下文简称年龄)进行了测算和研究.结果表明,珠江水体悬浮物颗粒有机碳(POC)是以现代碳为主并含有少量“老碳”的混合体;其年龄介于540～2050aBP之间,其中西江、北江悬浮物POC年龄相对较老,东江悬浮物POC年龄构成较为离散——既有较年轻的样品,又有较年老的样品,但以年轻的为主.悬浮物POCδ13C和Δ14C间呈类似正相关关系,这一关系实质上反映了流域土壤和母岩有机质在悬浮物中的构成,是流域内15～30cm以下剖面土壤有机碳同位素组成在河流悬浮物中的体现,反映了河流有机质的土壤来源深度;而流域内表层的土壤有机质因处于不稳定状态,进入河流后很快就被分解掉,难以表现出来.珠江流域中,土壤侵蚀以西江流域较重,东江流域较轻.
The carbon isotope composition (14C, 13C) and apparent age (hereinafter referred to as the “age”) of the Pearl River water body taken from 1998, 2000 and 2005 were studied and studied.The results showed that the suspended matter Particulate organic carbon (POC) is a mixture of modern carbon and a small amount of “old carbon”; its age ranged from 540 to 2050 aBP. Among them, the POC of Xijiang and Beijiang sediments is relatively old, POC age is relatively discrete - there are younger and older samples, but younger ones, POCδ13C and Δ14C showed a similar positive correlation, which reflects the relationship between the soil And the composition of organic matter in suspended matter in the parent rock are the organic carbon isotope composition of the soil below 15 ~ 30cm in the river basin, which reflects the depth of soil organic matter in the river. The soil organic matter In the Pearl River Basin, soil erosion is heavier in the Xijiang River Basin and lighter in the Dongjiang River Basin.