[Community structure characteristics of phytoplankton and related affecting factors in Hengshan Reservoir, Zhejiang, China].

In order to reveal the community structure characteristics of phytoplankton and the relationships with environmental factors in Hengshan Reservoir, the phytoplankton species composition, abundance, biomass and 12 environmental factors at 4 sampling sites were analyzed from March 2011 to February 2012. A total of 246 phytoplankton species were identified, which belong to 78 genera and 7 phyla. The dominant species were Melosira varians, M. granulate, Cyclotella meneghiniana, Asterianella formosa, Synedra acus, Achnanthes exigua, Ankistrodesmus falcatus, Oscillatoria lacustris, Cryptomonas erosa, Chroomonas acuta, Phormidium tenue and Microcystis aeruginosa, etc. Seasonal variations of species were obvious. The annual abundance and biomass of the phytoplankton were 0.51 x 10(5)-14.22 x 10(5) ind x L(-1) and 0.07-1.27 mg x L(-1), respectively. The values of the Margelef index, Pielou index and Shannon index of the phytoplankton community were 1.10-3.33, 0.26-0.81 and 0.51-2.38, respectively. The phytoplankton community structure was of Bacillariophyta-Cryptophyta type in spring and winter, of Chlorophyta-Cyanophyta type in summer, and of Bacillariophyta type in autumn. Canonical correlation analysis (CCA) showed that temperature, transparency, chemical oxygen demand and pH had the closest relationships with the phytoplankton community structure in the reservoir. Water quality evaluation showed that Hengshan Reservoir was in a secondary pollution with a meso-trophic level.

[Fluorescence quench of bovine serum albumin by pentachlorophenol].

The interaction between pentachlorophenol and bovine serum albumin (BSA) were studied using fluorescence spectra and ultraviolet-visible light absorption spectra. The results show that the fluorescence of BSA was quenched regularly by the pentachlorophenol, the mechanism of the fluorescence quench was investigated. The binding constants and thermodynamic parameters of pentachlorophenol with BSA were obtained at different temperatures. The hydrophobic interaction force and electrostatic force played a main role in the binding of pentachlorophenol with BSA. The distances of binding site between pentachlorophenol and BSA were also obtained according to the theory of Forster's non-radiative energy transfer.