| Water eutrophication is the cause of formation, freshwater lakes bloom outbreak will lead to the degradation of ecosystem structure, function and ecological disasters. In this paper, by adding different concentrations of N, P, Si and EDTA-Fe to indoor culture Xiaoxingkai Lake of natural phytoplankton community. Experiments according to orthogonal experiment the intense divided into 16 groups, experimental period for 12 days, taking a sample every 2 days. Qualitative and quantitative investigations were conducted to the phytoplankton of samplings, and calculated the growth rate of phytoplankton growth and the generation time. Used multi-factor variance analysis of SPSS 16.0 statistical analysis software method, analysis and discussed of the relationship between the nutrient and the phytoplankton. To provide the scientific evidence and reference for the protection and management in Xiaoxingkai Lake and other freshwater lakes.Research shows the indoor experiment of phytoplankton, A total of 8 phyla,76 species were identified in Xiaoxingkai Lake.Among which, the majority were Chlorophyta (38 species), Bacillariophyta (18 species), Cyanophyta(10species), and the other 10 species were also identified. That is slightly different from natural water phytoplankton community structure, for small xingkai lake natural water phytoplankton identification, a total of 8 phyla,55 species and varieties.Bacillariophyta (20 species),Chlorophyta (16 species), Cyanophyta (9species), and the other 9 species were also identified. This may be due to added different concentration of nutrient and phytoplankton community structure has changed. The empirical analysis revealed that the group of applied nitrogen to 32μmol/L,phosphorus to 2μmol/L, silicon to 0.3μmol/L,EDTA-Fe to 9μmol/L has most species of phytoplankton. The group of applied nitrogen to 8μmol/L. phosphorus to 0.5μmol/L, silicon to 0.3μmol/L, EDTA-Fe to 5μmol/L has 44 kinds of phytoplankton. The group of applied nitrogen to 16μmol/L, phosphorus to 0.1μmol/L, silicon to 3μmol/L, EDTA-Fe to 9μmol/L has the lowest species of phytoplankton.The experiment found 12 dominant species, the 3th group and the 16th group were the most that have 8 species of dominant species; The 12th group and the 14th group had 7 kinds of dominant species;the 11 th group had the lowest kinds of dominant species. Microcystis elabens, Melosira granulata var.angustissima and Cyclotella meneghiniana were the dominant species in each group.Microcystis elabens and Cyclotella meneghiniana had the highest dominance in the groups.In each group had differences between phytoplankton abundance and biomass. From each group average abundance of phytoplankton, the 8th group had the maximum average of phytoplankton abundance, it was belong to low nitrogen, high phosphorus, silicon and EDTA-Fe nutrient concentration. The group 5th had minimum average phytoplankton abundance, it was belong to low nitrogen,EDTA-Fe and high phosphorus、silicon. From each group average biomass of phytoplankton, the 8th group had the maximum average of phytoplankton biomass, followed by the 16th group and the group 1 had minimum average phytoplankton biomass, at this time nutrient concentrations were the lowest level.Through experiment study, freshwater phytoplankton of nutrient demand were different between the ocean phytoplankton. Ocean high nutrient low chlorophyll waters characterized by iron limitation, but the concentration of iron in fresh water lakes is far higher than the ocean and it will not limiting factor for the phytoplankton growth, and nitrogen and phosphorus in the copy of the eutrophication of waters is on the high side.By the Xiao xingkai Lake phytoplankton indoor cultivation, in applied different concentrations of nitrogen, phosphorus, silicon and EDTA-Fe under the condition to study of phytoplankton growth rate and the generation time. During the 12 days of training period, the influence of four factors on the phytoplankton growth order was:P>Si>N>EDTA-Fe. By analysis of variance results showed that optimal levels of each factor:when applied nitrogen concentration was 32μmol/L algae growth condition was good for the best level, belong to high N type. When applyed phosphorus concentrations was 1μmol/L algae growth condition was good for the best level, belonged to the high concentration of phosphorus type. When applied silicon concentration was 0.3μmol/L algae growth condition was good for the best level, belonged to the low silicon type. When applied EDTA-Fe concentration was 3μmol/L algae growth condition was good for the best level, belonged to the low iron. |
PDF Full Text Request