| 摘要: |
| 由于湖泊水库等养殖水体中鱼饲料等营养物质的投加，导致藻类大量繁殖并严重威胁养殖水体生态平衡，了解养殖水环境中藻类之间的竞争特点和生存策略对揭示水华暴发机制具有重要意义。实验采用无氮磷的M-11培养基，加入鱼饲料制备成改进的M-11培养基，以铜绿微囊藻和斜生栅藻为实验对象，设定培养条件为：白天3000 lx，28℃，12h；夜间0 lx，20℃，12h。通过测定藻细胞密度和氮磷营养盐浓度，并应用改进的藻生长动力学方程和竞争方程，研究鱼饲料作为氮磷营养源时两种藻在单独培养和共生培养条件下的生长情况和竞争行为。结果表明：(1)单培养情况下，铜绿微囊藻的最大藻细胞密度为1411×104 cells/mL，约为斜生栅藻的2.6倍；斜生栅藻在实验初期(0~4 d)的平均比生长速率为0.405 d-1，显著大于铜绿微囊藻(0.124 d-1)。(2)共培养情况下，铜绿微囊藻的平均抑制率比斜生栅藻高22.6%，平均竞争抑制参数比斜生栅藻低2.009，斜生栅藻在竞争中占优势。(3)Lotka-Volterra方程、改进的Monod方程、改进的Logistic方程以及基于此方程导出的系列方程，能够描述铜绿微囊藻和斜生栅藻的生长、竞争、营养盐利用行为(R2=0.451~0.998)。(4)比较改进的M-11培养基与营养状态指数相近的常规无机盐培养基，发现改进的M-11培养基中两种藻在单培养和共培养情况下的最大藻细胞密度更高。(5)鱼饲料在水体中的营养盐释放特征有助于斜生栅藻在实验初期维持较高的比生长速率并快速利用营养盐，从而在共培养时易于取得竞争优势。研究结果可为养殖水体水华的防治提供理论指导和数据支持。 |
| 关键词: 铜绿微囊藻 斜生栅藻 鱼饲料 营养盐 种间竞争 |
| DOI：10.11693/hyhz20240800188 |
| 分类号: |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目）,天津市科学基金资助项目 |
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| EFFECTS OF FISH FEED ON THE GROWTH AND INTERSPECIFIC COMPETITION OF MICROCYSTIS AERUGINOSA AND SCENEDESMUS OBLIQUUS |
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Li Gaocheng,Kong Wenwen,Liu Deze,Wei Mengjiao,Guo Zhi,Huang Suiliang
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1.Nankai University College of Environmental Science and Engineering;2.Hebei University of Technology，School of Energy and Environmental Engineering
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| Abstract: |
| The addition of fish feed and nutrients in aquaculture water bodies ,such as lakes and reservoirs, can lead to excessive algal growth, disrupting ecological balance. Understanding the competitive dynamics of algae in these enviornments is crucial for elucidating algal bloom mechanims. In this study, we modified nitrogen-free and phosphorus-free M-11 medium by adding fish feed and utilized Microcystis aeruginosa and Scenedesmus obliquus as experimental subjects. Culture conditions were set as follows: daytime 3000 lx, 28°C during the day for 12 hours, and 0 lx, and 20°C at night for 12 hours. Algal cell density and nutrient (nitrogen and phosphorus) concentrations were measured, and improved algal growth kinetic and competition models were applied to assess growth and competitive behavior under both monoculture and co-culture conditions. The results showed that:(1) the maximum algal density of M. aeruginosa was 1411×104 cells/mL, which was 2.6 times higher than that of S. obliquus;Furthermore, the average specific growth rate of S. obliquus at the beginning of the experimental period (0-4 d) was 0.405 d-1, which was significantly higher than that of M. aeruginosa (0.124 d-1). (2) The average inhibition rate of M. aeruginosa was 22.6% higher than that of S. obliquus under co-culture, while the average competitive inhibition parameter for M. aeruginosa was 2.009 lower than that of S. obliquus, Indicating that S. obliquus was dominant in competition. (3) The Lotka-Volterra equation, the improved Monod equation, the improved Logistic equation, and the derived relationship equations based on the improved Logistic equations effectively described the growth, competition, and nutrient utilization behaviors of M. aeruginosa and S. obliquus (R2=0.451~0.998). (4) In comparisons between the modified M-11 medium and conventional inorganic media with similar trophic state indices, both algae species achieved higher maximum cell densities in the modified M-11 medium under both monoculture and co-culture conditions. (5) The nutrient release characteristics of fish feed in water facilitated Scenedesmus obliquus in maintaining a higher specific growth rate during the initial stages of the experiment and enabled rapid nutrient utilization , thus providing it with a competitive advantage in co-culture. The study provides theoretical guidance and data support for the prevention and control of algal blooms in aquaculture waters. |
| Key words: Microcystis aeruginosa Scenedesmus obliquus fish feed nutrients interspecific competition |