胶州湾赤潮暴发水体中溶解有机物质荧光特征

Fluorescence Characteristics of Dissolved Organic Matter During Algal Bloom in Jiaozhou Bay

利用荧光激发-发射矩阵光谱(Excitation-Emission Matrix Spectroscopy,EEMS)技术研究了胶州湾2004-02赤潮暴发期间水体中溶解有机物类蛋白和类腐殖质荧光特性,探讨了各种荧光性质与浮游植物增殖、溶解有机碳、盐度、溶解氧和pH的关系,并对切向超滤前后类蛋白和类腐殖质荧光的变化进行了初步评估.结果表明,赤潮过程中溶解有机物类蛋白荧光较强而类腐殖质荧光较弱,并且高和低激发波长类蛋白荧光同源;类蛋白和类腐殖质荧光强度与叶绿素a的对应关系与浮游植物的增殖阶段有关,但整体趋势上却是随着浮游植物量的增大而增强,并且浮游植物量越大,新生成的有机物质占的比例也越大;类蛋白荧光以及类蛋白和类腐殖质荧光强度之比与溶解有机碳具有较好的正相关性,表明赤潮过程中溶解有机物主要由新生成的物质组成;盐度、溶解氧和pH对类蛋白和类腐殖质荧光的影响很小;切向超滤前后类蛋白和类腐殖质荧光峰的位置基本一致,切向超滤前后荧光平衡差于溶解有机碳平衡,在切向超滤的评价上,荧光只能作为溶解有机碳平衡的一个补充.

Fluorescence excitation-emission matrix spectroscopy （EEMS） was employed to characterize the dissolved organic matter （DOM） in algal bloom seawater of Jiaozbou Bay in February, 2004. The relationships of DOM fluorescence characteristics with phytoplankton multiplication, dissolved organic carbon （DOC）, salinity, dissolved oxygen and pH were discussed. In addition, the protein-like and humic-like fluorescence changes fore and aft cross-flow ultrafiltration （CFF） were primarily evaluated. The results show that the intensities of high and low-excitation protein-like fluorescence, which have the same sources, are stronger than that of humic-like during algal bloom. Both correlations between protein-like fluorescence intensities and chlorophyll-a and between humic-like fluorescence intensities and chlorophyll-a are relevant to the phytoplankton multiplication. As a whole, the fluorescence intensities of protein-like and humic-like increases with chlorophyll-a increasing. Furthermore the ratios of new to old DOM increase with phytoplankton biomass increasing. Good positive correlations between protein-like fluorescence intensities and DOC and between the ratios of protein-like to humic-like fluorescence intensities and DOC suggest that the DOC is mainly composed of newly produced matter during algal bloom. Some inorganic factors, such as salinity, dissolved oxygen and pH, have little effects on protein like and humic-like fluorescence. Fore and aft the CFF experiments, the positions of protein-like and humic like fluorescence peaks have little alteration, the balance of fluorescence intensity is not so good as organic carbon mass balance as a whole. Fluorescence balance should be used only as a supplementary technique for evaluating contaminations or loss by organic carbon mass balance.