Environmental characteristics and phytoplankton community structure were investigated in two aquaculture areas in Dapeng Cove of Daya Bay, South China Sea, between April 2005 and June 2006. Phytoplankton abundance ranged between 5.0 and 8877.5 cells/mL, with an average of 751.8 cells/mL. The seasonal cycle of phytoplankton were demonstrated by frequent oscillations, with recurrent high abundances from late spring to autumn and a peak stage in late winter. Diatoms were the predominant phytoplankton group, accounting for 93.21% of the total abundance. The next most abundant group was the dinoflagellates, which made up only 1.24% of total abundance. High concentrations of Alexandrium tamarense （Lebour） Balech with a maximum of 603.0 cells/mL were firstly recorded in this area known for high rates of paralytic shellfish poisoning （PSP） contamination. Temperatures and salinities were within the suitable values for the growth of phytoplankton, and were important in phytoplankton seasonal fluctuations. The operation of the Daya Bay Nuclear Power Station （DNPS） exerts influences on the phytoplankton community and resulted in the high abundances of toxic dinoflagellate species during the winter months. Dissolved inorganic nitrogen （DIN） and dissolved silicate （DSi） were sufficient, and rarely limited for the growth of phytoplankton. Dissolved inorganic phosphorus （DIP） was the most necessary element for phytoplankton growth. The enriched environments accelerated the growth of small diatoms, and made for the shift in predominant species from large diatom Rhizosolenia spp. to chain-forming diatoms such as Skeletonema costatum, Pseudo-nitzschia spp. and Thalassiosira subtilis.
以浮石为载体、TiO2粉末浸渍法制备TiO2/浮石催化剂,光催化处理邻苯二甲酸二甲酯(DMP)微污染水,对催化剂的催化效率、耐用性进行考察,并探讨水体pH、HCO3-、Cl-、SO42-和腐殖酸对降解效率的影响。结果表明,当DMP初始质量浓度20 mg.L-1,催化剂投加量10 g.L-1,光降解100 min DMP降解率达94.5%,催化剂重复使用二次后DMP降解率仍在80%以上;当溶液pH为3.0时降解率下降至76.5%,表明酸性体系不利于DMP的光催化降解;3种阴离子对降解反应都有抑制作用,抑制强度为HCO3->Cl->SO42-;腐殖酸对该降解反应抑制作用明显,抑制作用随浓度增大而增强。TiO2/浮石催化剂在曝气条件下形成流化状态,使TiO2充分接触水样和吸收光源而具备较高催化效率,另外涂膜稳定牢固,可反复使用。
