珠江三角洲环境梯度上葫芦藓中硫、氮含量和δ^(13)C、δ^(15)N的差异及其环境指示

Spatial Difference of the Contents of Sulfur, Nitrogen, and Isotopes of Carbon and Nitrogen of Funaria Hygrometrica in the Pearl River Delta Region and Its Environmental Implication

以华南地区广泛分布的葫芦藓为研究对象,以珠江三角洲环境梯度上的中心城区广州、近郊区肇庆及边缘区怀集3个地理单元作为样品采集地,对样本葫芦藓植物中的硫、氮元素含量和δ13C、δ15N的组成进行了研究。结果表明:葫芦藓植物中硫含量与工业化程度表现出正相关关系,其中硫含量广州、肇庆和怀集依次为2 485.86、1 778.15、1 339.84 mg/kg;葫芦藓氮含量与工业化程度表现出正相关关系,广州、肇庆和怀集依次为2 106.50、2 007.39和1 661.88 mg/kg;葫芦藓的C/N值与交通量呈负相关关系,其中C/N值广州为18.377,肇庆18.513,怀集23.905,3地C/N值大小差异揭示了从广州到怀集的环境梯度上,大气氮的主要组份发生了变化,即广州大气中的氮元素来源以工业排放的NOx-N(硝态氮)为主,怀集大气中的氮元素来源以农业排放的NHx-N(铵态氮)为主。

The rapid economic development of the Pearl River Delta region has caused over-exploitation of resources, environmental pollution and ecosystem function damage. In order to seek the spatial gradient of environment, the S, N and C contents of Funaria hygrometrica are studied in three typical areas which are Guangzhou, Zhaoqing and Huaiji, representing the core, periphery and edge of the Pearl River Delta, respectively.Analytical results show that there is positive correlation between the sulfur and nitrogen contents in Funaria hygrometrica and the degree of industrialization. The contents of the sulfur in Funaria hygrometrica of Guangzhou, Zhaoqing and Huaiji City are 2 485.86, 1 778.15 and 1 339.84 mg/kg respectively. The contents of the nitrogen in Funaria hygrometrica of the three cities are 2106.5 mg/kg, 2 007.39 mg/kg and 1 661.88 mg/kg,respectively, and both the contents of sulfur and nitrogen in Guangzhou are the highest, while those in Huaiji the lowest. However, the correlation between the C/N ratio of Funaria hygrometrica and the degree of industrialization is negative. The C/N ratios of Funaria hygrometrica are 18.377, 18.513 and 23.905 in Guangzhou, Zhaoqing and Huaiji, respectively, and C/N is the lowest in Guangzhou and the highest in Huaiji.That signifies that major components of elements N changes in atmosphere. The element N in the atmosphere of Huaiji originates from NHx-N（ammonium） based on the emission from agriculture, while that in Guangzhou originates from NOx-N（nitrate） based on the emission from industry mainly.