Dynamics of phytoplankton communities in the Jiangdong Reservoir of Jiulong River,Fujian, South China

Phytoplankton blooms occurring in the Jiangdong Reservoir of Jiulong River, Fujian Province, South China, are a potential source of contamination of the drinking water of Xiamen （Amoy） City. To understand the main factors governing phytoplankton composition and succession, we sampled phytoplankton and measured environmental parameters in the reservoir, weekly or biweekly from Jan. 2010 to Feb. 2012. We identified 123 species of phytoplankton from 7 phyla and 74 genera. The major phyla were Chlorophyta, Bacillariophyta, Cryptophyta, Cyanophyta, and Dinophyta. The main trend in the succession of phytoplankton was from prevalence of Cryptophyta-Bacillariophyta communities to those of Chlorophyta-Cyanophyta. High cell concentrations of Cryptophyta, predominantly Komma caudate, Cryptomonas marssonii, and Cryptomonas erosa, were present in winter, associated with low river discharge and cold water. Bacillariophyta, primarily Cyclotella meneghiniana, Aulacoseira granulata, and Aulacoseira granulata var. angustissima, dominated in early spring, coinciding with high turbulence and low irradiance. During early summer and autumn, Chlorophyta, comprising Scenedesmus quadricauda, Dictyosphaerium ehrenbergianum, and Pandorina sp. were prevalent during conditions of warmer water temperatures and low turbulence. Cyanophyta, with dominance ofPseudanabaena mucicola, Merismopedia tenuissima and Raphidiopsis sp. increased throughout the summer, coinciding with higher water temperatures and lower nutrient concentrations. Dinophyta content was occasionally high during winter and summer. Peridiniopsis penardii （Dinophyta） bloomed during winter 2009, with a persistently high biomass recorded into early spring. Canonical correspondence analysis indicated that phytoplankton communities were influenced by river discharge, irradiance, water temperature, and nutrient concentrations.     

质子核磁共振法测定腐植酸结构特征

作者采用质子核磁共振法对厦门港沉积物中的腐值酸进行了测定.在对腐值酸的活性官能团、元素组成及红外光谱测定结果的基础上,讨论了腐植酸的结构特征,实验结果给出了有关腐植酸中脂肪族化台物的构成单元、芳香族化合物上的取代官能团类型.结果表明,采用以DMSO-d为溶剂比采用以NaOD为溶剂所得到的腐植酸的H-NMR谱图效果要好,这一结果对于揭示不同来源和发育阶段的腐植酸在结构特征上的差异是有所帮助的.