九龙江口红树林保护区水体浮游植物群落结构及营养状态评价

Phytoplankton community structure and assessment of trophic state in Jiulongjiang Estuary Mangrove Nature Reserve

于2016年1月(冬季)、4月(春季)、7月(夏季)以及10月(秋季)对九龙江口红树林保护区的浮游植物多样性组成及其时空变化进行研究.结果表明,福建九龙江口红树林保护区共采集到浮游植物5门91属138种,其中硅藻占50.00%、绿藻占31.16%、蓝藻占8.70%、甲藻和裸藻各占5.07%.主要优势种为具槽直链藻(Melosira sulcata)、中肋骨条藻(Skeletonema costatum)、条纹小环藻(Cyclotella stratia)、舟形藻(Navicula sp.)、粗针杆藻(Synedra robusta)和菱形藻(Nitzschia sp.);浮游植物细胞数量在0.82×105~4.55×105个/dm3之间,年平均数量为1.97×105个/dm3.浮游植物种类时空变化明显,而数量的空间变化较大,季节变化不太明显.Shanno-Wiener指数、Margalef丰富度指数和Pielou均匀度指数变化范围分别为2.10~3.55、1.05~3.61、0.78~0.95.多样性指数及浮游植物生物量评价结果显示,九龙江口红树林保护区的水体为中营养状态,水质较好,但仍应加强对陆源径流和养殖废水排放进入红树林的控制和管理.

To investigate phytoplankton species composition and biodiversity in Jiulongjiang Estuary Mangrove Nature Reserve( JEMNR),seasonal sampling of phytoplankton was carried out at 6 stations from January to October in 2016. The trophic state of the water in the reserve was assessed with Shannon-Wiener diversity index,Pielou evenness index and Margalef abundance index. A total of 138 phytoplankton species in 91 genera and 5 phyla had been identified in this mangrove wetland. Bacillariophyta dominated the phytoplankton community,with 50. 00% of the total species,followed by Chlorophyta( 31. 16%),Pyrrophyta( 8. 70%),Cyanophyta( 5. 07%) and Euglenophyta( 5. 07%). The dominant species were Melosira sulcata,Skeletonema costatum,Cyclotella stratia,Navicula sp.,Synedra robusta and Nitzschia sp. Phytoplankton density ranged from 0. 82 × 105 to 4. 55 × 105 cells/dm3,with average value of 1. 97 × 105 cells/dm3. In contrast to the remarkable seasonal and spatial variation of species compositions,the phytoplankton quantity was changed little with seasons though they varied spatially with sites. The diversity indexes of Shannon-Wiener,Margalef and Pielou were 2. 10 ~ 3. 55,1. 05 ~ 3. 61,0. 78 ~0. 95,respectively. According to the evaluation on the these index,it seemed that the water in mangrove wetland was not severely polluted. It was necessary to strictly control the wastewater and effluent discharging and inland run off into the mangrove.