生态基对大口黑鲈池塘养殖系统水质及能量收支的影响研究

为摸清生态基养殖池塘系统的能量流动规律,以放置生态基的大口黑鲈(Micropterus salmoides)池塘为研究对象,采用原位实验方法,研究了生态基对大口黑鲈池塘养殖系统的水质及能量收支的影响。实验期间,生态基可显著降低池塘水体中氨氮、硝态氮、总氮及总磷含量(P0.05),但对亚硝态氮、磷酸盐、底泥总氮和总磷含量无显著影响(P0.05);饵料投入是系统能量输入的主要来源,分别占对照组和实验组总输入能的53.26%和55.02%,其次为浮游生物生产,两组分别为45.92%和44.22%;浮游生物呼吸是能量输出的主要途径,分别占对照组和实验组总输出能的60.01%和56.68%,其次为养殖生物收获,两组分别为28.78%和31.99%;生态基实验组生物净产出能、光合能转化效率、饲料能转化效率及总能量转化效率均显著高于对照组(P0.05),而单位净产量耗饲料能和单位净产量耗总能则显著低于对照组(P0.05)。结果表明,在大口黑鲈池塘放置生态基能改善池塘环境,有效提高系统产出量及能量利用效率。     

白洋淀草型淀区沉水植物暴发期浮游植物群落特征

：Species composition,cell abundance,and biomass of phytoplankton were surveyed in 4 sampling zones with 4 sampling site in each zone in overgrowth of submerged macrophytes in Baiyangdian Lake (Shihoudian Sub-lake) in August 2018 to understand the community characteristics of phytoplankton during the explosive reproduction period of submerged macrophytes. The status of water quality was evaluated during the overgrowth period. A total of 68 species (51 genera) of phytoplankton were observed over a total cultured period,belonging to six major functional groups,i.e,Chlorophyta (30 species),Bacillariophyta (16 species),Cyanophyta (16 species),Euglenophyta (3 species),Pyrrophyta (1 species),and Cryptophyta (1 species),with phytoplankton abundance of 5.68×10—17.24×10 cells/L (average 9.13×10 cells/L)and phytoplankton biomass of 1.42—8.71 mg/L (average 4.61 mg/L). Redundancy analysis revealed that transparency,total dissolved solids,conductivity and pH were the most important environmental factors affecting the spatial distribution of phytoplankton species composition in summer. The water quality of Shihoudian Sub-lake was found to be β-meso-polluted to oligo-polluted judging from the phytoplankton diversity evaluation. Compared with algal regions and non-overgrowth period in Baiyangdian Lake,the characteristics of phytoplankton community in the overgrowth period of submerged macrophytes displayed a great difference.The finding provides support for ecological restoration and functional enhancement of macrophyte-dominated sub-lake.