【摘要】 通过溶解性有机碳(DOC)、紫外-可见吸收光谱及三维荧光激发发射矩阵(3DEEM)分析,研究崇明岛前卫湖有色溶解性有机质(CDOM)的分布和来源。结果发现,表层水中DOC的空间分布比较均匀,变化范围为5.87～7.02mg·L-1,平均值为6.35mg·L-1。吸收光谱分析表明,校正吸收系数a355在养殖区最高,为4.58m-1,并呈向两边逐渐递减的趋势,暗示养殖区CDOM可能存在陆源之外的其他来源。进一步的荧光指数(f450/500)分析证实了水生生物源的存在,同时也表明前卫湖水体的CDOM总体上并没有明显偏向陆源或者水生生物源(f450/500为1.50～1.84),而a355与DOC含量的比值和荧光指数存在显著正相关(r=0.787,n=10,P<0.01),说明养殖区存在一个比较明显的生物信号,其可能来源为藻类。三维荧光的分析结果表明,类腐殖酸组分普遍存在于前卫湖CDOM中,且空间差异不大;而类蛋白组分的分布差异较大,可能是影响前卫湖CDOM空间分布的主要因素,这与上述生物源的分析结果相吻合。更多还原

【Abstract】 Based on analysis of dissolved organic carbon (DOC),with the techniques of UV-visible absorption and three-dimensional excitation emission matrix (3DEEM),distribution and origin of chromophoric dissolved organic matter (CDOM) in Lake Qianwei,Chongming Island at the Yangtze River Estuary were explored. In the surface layer of the water body,DOC was evenly distributed,with concentration ranging from 5.87 to 7.02 mg·L-1 and averaging 6.35 mg·L-1. The UV-visible absorption revealed that the calibrated absorption coefficient a355 was the highest in the fish-culturing zone,reaching 4.58 m-1,and declining towards either side,which implied that there were other sources of CDOM besides terrestrial sources. Fluorescence index (f450/500) analysis proved presence of aquatic biological sources,and also indicated that the CDOM in the waterbody of Lake Qianwei did not show any significant trace of terrestrial or aquatic biological origin. However,the ratio of a355 and DOC showed a significant positive correlation with fluorescence index (r=0.787,n=10,P<0.01),suggesting a strong biological signal existed in the aquicultural zone,and it might come from phytoplankton production. 3-DEEM analysis show that humic-like components commonly existed in CDOM in this lake,and did not vary much in spatial distribution,while protein-like components did and presumably were the major factor affecting spatial distribution of CDOM.更多还原