辽东湾海域有色可溶性有机物荧光特征分析

摘要

为了分析辽东湾有色可溶性有机物 (Chromophoric dissolved organic matter, CDOM) 的分布特征,于2015年4月14日-5月3日采用"走航式"测量方法,分别获取了辽东湾海域32个站位表层、5、10 m 3个不同深度水层的CDOM荧光图谱、吸收系数和石油物质含量等数据.结果表明:表层 (0 m) CDOM的荧光图谱分为3种类型:单峰型、双峰型和三峰型,5、10 m深水层CDOM的荧光图谱主要为单峰型和双峰型;3种峰型均包含位于激发波长 (Ex) /发射波长 (Em) 为225~235 nm/325~350 nm的荧光峰,这主要是海水浮游植物自身降解产生的色氨酸产生的;在靠近海上油气开采平台和双台子河入海口的海域,油物质和CDOM的共同作用,使得位于这些区域的站点表层的荧光强度明显增强,荧光峰的范围也有所增大;表层、10 m深水层荧光强度最大值和最小值随站位的走势基本一致,而5 m深水层的走势就比较复杂;无论是哪种类型的荧光峰,其位置随着水深的增加基本保持不变,荧光强度随水深变化规律不明显.本研究中建立的由荧光峰强度 (Af) 和CDOM在440 nm处吸收系数 [ag(440) ] 的比值来求解光谱斜率(S) 的模型,可为利用荧光和可见光遥感技术反演光谱斜率S提供一种新方法.%The fluorescence spectra and absorption coefficients of chromophoric dissolved organic matter (CDOM) and levels of petroleum-polluted materials were analyzed by navigational style at three depths of 0,5 and 10 meters at 32 stations in Liaodong Bay from April 14,2015 to May 3,2015 to understanding of distribution characteristics of CDOM in Liaodong Bay. The results showed that three characteristics of the CDOM fluorescence were observed throughout the Liaodong Bay. Firstly the fluorescent spectra of CDOM in surface sea water(0 m) were divided into three types of curves,monopeak,dual peak and tripeak;fluorescence spectra of CDOM in the 5 m and 10 m water in the east coast were mainly monopeak,and dual peak;all fluorescence spectra had a fluorescence peak at excita-tion wavelength/emission wavelength of 225-235 nm/325-350 nm due to the release of tryptophan produced by the degradation of marine phytoplankton. Secondly the fluorescence intensity of surface sea water was obviously in-creased,and the scope of the fluorescence peak was also expanded in Shuangtaizihe Estuary and close to the off-shore oil platform with combined effects of oil substances and CDOM. Thirdly distribution trends of the maximum and minimum values of fluorescence intensity were basically the same at 0 m and 10 m water layer,but the fluores-cence intensity change was relatively complicated at 5 m water layer. There was no significant relationship between fluorescence intensity and water depth,without changes in position of all types of fluorescence peaks with depth.Fi-nally a model was established for solving the spectral slope S from the fluorescence peak intensity Afand CDOM ab-sorption coefficient at 440 nm ag(440),which provides a new method for the inversion of spectral slope S by using fluorescence and visible light remote sensing.