光照对普通小球藻和鱼腥藻生长竞争的影响

摘要

研究光照对藻类生长竞争的影响对于揭示如何通过控制环境因子促进有益藻类生长繁殖、抑制有害藻类生长繁殖，并最终实现利用藻类调节养殖生态环境和提高水体初级生产力具有重要意义。为此，试验设置了660、2200、4400、6600 lx 4个光照梯度，通过测算比生长速率、生长曲线、竞争抑制参数，研究不同光照强度对普通小球藻（Chlorella vulgaris）和鱼腥藻（Anabaena sp.strain PCC）生长和种间竞争的影响。结果表明：单种培养条件下，鱼腥藻和普通小球藻的最大藻细胞浓度呈现出随着光照强度的增强而升高的趋势；普通小球藻在660、2200、4400、6600 lx光照强度下达到最大藻细胞浓度的时间分别为14、15、17、17 d，最大藻细胞浓度分别为961.2×104、1858.3×104、3258.8×104、3227.2×104 cells·mL-1；鱼腥藻在4个光照下达到最大藻细胞浓度的时间分别为17、18、21、21 d，最大藻细胞浓度分别为4018.3×104、8325.0×104、10552.8×104、10073.4×104 cells·mL-1。共同培养条件下，光照强度对两种藻的竞争作用产生显著影响。同时，种间竞争抑制参数的测算结果表明，4组光照强度下，鱼腥藻对普通小球藻的竞争抑制参数（α）均小于普通小球藻对鱼腥藻的竞争抑制参数（β）；光照强度6600 lx时，普通小球藻对鱼腥藻的竞争抑制参数（β）最大，为7.94；光照强度4400 lx时，鱼腥藻对普通小球藻的竞争抑制参数（α）最大，为0.45。根据Lotka-Volterra竞争模型中两物种的种间竞争结局可初步判断，光照强度2200 lx时，普通小球藻在竞争中占优势；光照强度为660、4400、6600 lx时，鱼腥藻和普通小球藻不稳定共存。%Chlorella vulgaris and Anabaena sp. are the most common algae in eutrophication ponds. In order to know the growth process of the two species of algae in eutrophication ponds and the relationship between algae growth and light intensity, the experiment was carried out to research the interspecies competition between Chlorella vulgaris and Anabaena sp. at different light intensity (660, 2 200, 4 400, 6 600 lx) by the methods of special growth rate, growth curve and inhibition parameters through indoors experiment. For the experiment could help clarify how to promote the growth of useful algae and restrain the growth of harmful algae by the way of regulating the environment factors, so the study is very important for regulating aquaculture eco-environment and improving primary productivity of water body. The results indicated that maximum biomass of both Chlorella vulgaris and Anabaena sp. increased with the increase of light intensity in the uni-culture system, and the maximum biomass of Chlorella vulgaris in the light intensity of 660, 2200, 4 400, 6 600 lx were 961.2×104, 1 858.3×104, 3 258.8×104, 3 227.2×104 cells·mL-1 respectively, and the maximum biomass of Anabaena sp. in the light intensity of 660, 2 200, 4 400, 6600 lx were 4 018.3×104, 8 325.0×104, 10 552.8×104, 10 073.4×104 cells·mL-1 respectively. Light intensity could influence the competition between Chlorella vulgaris and Anabaena sp. significantly. The results of inhibition parameter of interspecies competition showed that the inhibition parameters of Anabaena sp. against Chlorella vulgaris were all lower than that of Chlorella vulgaris against Anabaena sp. at the experiment condition. The inhibition parameter of Chlorella vulgaris against Anabaena sp. reached the peak at the 6 600 lx group, and the maximum was 7.94. The inhibition parameter of Anabaena sp. against Chlorella vulgaris reached the peak at the 4 400 lx group, and the maximum was 0.45. Chlorella vulgaris dominated in the 2 200 lx group, and Chlorella vulgaris and Anabaena sp. could unstably coexist in the 660, 4 400 and 6 600 lx groups based on the competition model of Lotka-Volterra.