氮磷质量浓度对普通小球藻和鱼腥藻生长竞争的影响

摘要

研究氮磷质量浓度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，并利用藻类调节养殖环境和提高水体初级生产力具有重要意义。设置了4个氮磷质量浓度梯度（N 0.18µg·mL-1，P 0.025µg·mL-1；N 0.36µg·mL-1，P 0.050µg·mL-1；N 0.72µg·mL-1，P 0.100µg·mL-1；N 3.60µg·mL-1，P 0.500µg·mL-1），通过测算比生长速率、生长曲线、竞争抑制参数，研究了不同氮磷质量浓度对普通小球藻（Chlorella vulgaris）和鱼腥藻（Anabaenasp. strain PCC）生长和种间竞争的影响。结果表明，在单种培养体系中，普通小球藻和鱼腥藻的最大藻细胞数量均随氮磷质量浓度的增加而增加，最大藻细胞数量分别为198.9×105 cells·mL-1和424.8×105 cells·mL-1；氮磷质量浓度对藻类的竞争能够产生明显影响，在共培养体系中，鱼腥藻的最大藻细胞数量表现为：中高氮磷组（208.9×105 cells·mL-1）>中低氮磷组（98.3×105 cells·mL-1）>高氮磷组（64.7×105 cells·mL-1）>低氮磷组（45.3×105 cells·mL-1）。同时，种间竞争抑制参数的测算结果表明，4组氮磷质量浓度下鱼腥藻对普通小球藻的竞争抑制参数（α）分别为2.599、0.564、0.772、1.618，普通小球藻对鱼腥藻的竞争抑制参数（β）分别为0.434、0.321、0.466、-8.899，鱼腥藻对普通小球藻的竞争抑制参数（α）均大于普通小球藻对鱼腥藻的竞争抑制参数（β）；低氮磷质量浓度时，鱼腥藻对普通小球藻的竞争抑制参数（α）最大，为2.599；中高氮磷质量浓度时，普通小球藻对鱼腥藻的竞争抑制参数（β）最大，为0.466。根据Lotka-Volterra竞争模型中的两物种竞争结局可初步判断，低、中高氮磷、高氮磷质量浓度时，鱼腥藻在竞争中占优势；中低氮磷质量浓度时，鱼腥藻和普通小球藻稳定共存。%Chlorella vulgaris andAnabaenasp 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 concentrations of nitrogen and phosphorus, the experiment was carried out to research the interspecies competition betweenChlorella vulgaris andAnabaenasp at different nitrogen and phosphorus concentrations (N 0.18 µg·mL-1, P 0.025 µg·mL-1; N 0.36 µg·mL-1, P 0.050 µg·mL-1; N 0.72 µg·mL-1, P 0.100 µg·mL-1; N 3.60 µg·mL-1, P 0.500 µg·mL-1) 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 bothChlorella vulgaris andAnabaenasp increased with the increase of nitrogen and phosphorus concentrations in the uni-culture system, and the maximum biomass ofChlorella vulgaris andAnabaenasp were 198.9×105 and 424.8×105cells·mL-1 respectively. Nitrogen and phosphorus concentrations could influence the competition between Chlorella vulgaris andAnabaenasp significantly. The maximum biomasses ofAnabaenasp in co-culture system were as follows: (TN 0.72 µg·mL-1, TP 0.100 µg·mL-1) group> (TN 0.36 µg·mL-1, TP 0.050 µg·mL-1) group> (TN 3.60 µg·mL-1, TP 0.500 µg·mL-1) group> (TN 0.18 µg·mL-1, TP 0.025 µg·mL-1) group, and maximum biomasses were 208.9×105, 98.3×105, 64.7×105, 45.3×105cells·mL-1 respectively. The results of inhibition parameter of interspecies competition showed that the inhibition parameters ofAnabaenasp againstChlorella vulgaris were 2.599, 0.564, 0.772, 1.618 respectively and that ofChlorella vulgarisagainst Anabaenasp were 0.434, 0.321, 0.466, -8.899 respectively, that is to say, the inhibition parameters ofAnabaenasp againstChlorella vulgaris were all larger than that ofChlorella vulgarisagainst Anabaenasp at the experiment conditions. The inhibition parameter ofAnabaenasp againstChlorella vulgaris reached the peak at the (TN 0.18 µg·mL-1, TP 0.025 µg·mL-1) group, and the maximum was 2.599. The inhibition parameter of Chlorella vulgaris againstAnabaenasp reached the peak at the (TN 0.72 µg·mL-1, TP 0.100 µg·mL-1) group, and the maximum was 0.466.Anabaenaspdominated in the (TN 0.18 µg·mL-1, TP 0.025 µg·mL-1), (TN 0.72 µg·mL-1, TP 0.100 µg·mL-1) and (TN 3.60 µg·mL-1, TP 0.500 µg·mL-1) groups, and Chlorella vulgaris andAnabaenasp could stably coexist in the (TN 0.36 µg·mL-1, TP 0.050 µg·mL-1) group based on the competition model of Lotka-Volterra.