| 基于香溪河背景下小球藻对不同形态氮素吸收动力学研究 |
| Variation in Nitrogen Uptake Kinetics by Chlorella Based on the Water Environment of Xiangxi Bay |
| 投稿时间：2015-07-09 修订日期：2016-03-04 |
| DOI：10.15928/j.1674-3075.2015.06.002 |
| 中文关键词:小球藻 氨氮 硝氮 吸收速率 吸收动力学 香溪河 |
| 英文关键词:Chlorella ammonium nitrogen nitrate nitrogen uptake rate uptake kinetics Xiangxi River |
| 基金项目:国家自然科学基金面上项目（51179095）；国家自然科学基金青年基金项目（51009080；51009081；51209123） |
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| 中文摘要: |
| 选取香溪河绿藻水华爆发时优势藻种—小球藻（Chlorella），经过分离纯化后作为实验原材料，分别检测了培养液中氨氮和硝氮的浓度，分析了小球藻对氨氮和硝氮吸收动力学特征以及不同氮素对其吸收速率的影响。实验表明，当氨氮浓度为11.62～2.97 mg/L，实验第2~3天时，小球藻氨氮去除效率不断加强，达到74.44%；当硝氮浓度为10.55～0.047 mg/L；实验第2~5天时，硝氮去除效率也不断加强，达到96.92%。无论是氨氮还是硝氮的培养条件下，小球藻在实验初始阶段都保持着较高的吸收速率，分别为1.44 mg/h和0.97 mg/h，随着培养介质中氮素浓度不断下降，其吸收速率也随之下降，其中用氨氮培养的小球藻在第3天达到最大吸收速率，为1.44 mg/h；用硝氮培养的小球藻在第4天达到最大吸收速率，为0.97 mg/h。小球藻对氨氮和硝氮的最大半饱和常数分别为2.85 mg/L和5.09 mg/L，表明单一氮源培养小球藻时，小球藻对氨氮更具有亲和力。实验结果为研究小球藻对氮素吸收速率从而控制小球藻生长提供理论依据，有助于通过调整、改变营养盐的输入通量及输入类型抑制小球藻繁殖，避免绿藻水华的发生。 |
| 英文摘要: |
| Xiangxi River is the largest tributary of the upper section of Three Georges Reservoir. Inputs of nitrogen and phosphorus and the backwater effect (after the impoundment reached 139 m) have caused serious Chlorophyta and Dinoflagellates blooms in Xiangxi Bay. A source of nitrogen is required for plant growth and primary production in lakes and rivers. Different species of fresh water algae display differences in the uptake of different forms of nitrogen and even the same species displays different uptake rates for different forms of nitrogen. In this study, the uptake kinetics of ammonium nitrogen and nitrate nitrogen by Chlorella (the dominant algae species in Xiangxi Bay algae blooms) was analyzed. Chlorella was cultured in media with ammonium sulfate (Treatment 1) and sodium nitrate (treatment 2) as the only nitrogen source. The TN concentration in both treatments was similar to the annual average TN concentration of Xiangxi Bay. The uptake rate of ammonium nitrogen and nitrate nitrogen by Chlorella was measured in both treatments at a light intensity of 100.8 ?mol/(m2.s), a temperature of 20℃ and pH 9.0 (the average annual pH of Xiangxi Bay). At the beginning of the test, media samples were collected to determine the original concentrations of chlorophyll, ammonium nitrogen and nitrate nitrogen. Samples were then collected at 9:00 each morning until the medium was nearly exhausted after nine days. Chlorophyll was determined according to Water and Wastewater Monitoring Analysis Methods, ammonium nitrogen by the Nessler colorimetric method and nitrate nitrogen by the sulfamic acid spectrophotometric method. When the concentration of ammonium nitrogen was in the range 11.62 mg/L-2.97 mg/L, the uptake efficiency of Chlorella increased over time, reaching 74.44% on day 2 and day 3. When the concentration of nitrate nitrogen was in the range 10.55 mg/L-0.047 mg/L, the uptake efficiency increased to 96.92% from day 2 to day 5. With both forms of nitrogen, the uptake rate by Chlorella was high, reaching a maximum of 1.44 mg/h on day 3 in Treatment 1 and 0.97 mg/h on day 4 in Treatment 2. As the concentration of nitrogen in the media decreased, the uptake rate by Chlorella also declined. The half-saturation constant (Ks) of Chlorella was 2.85 mg/L in Treatment 1 (ammonium nitrogen) and 5.09 mg/L in Treatment 2 (nitrate nitrogen), indicating that Chlorella prefers ammonium nitrogen. The study provides a theoretical basis for controlling Chlorella growth, suggesting that algae blooms could be controlled by manipulating the input quantity and form of nitrogen. |
| 胡雪,刘德富,杨正健,黄钰铃,李竹.2015.基于香溪河背景下小球藻对不同形态氮素吸收动力学研究[J].水生态学杂志,36(6):8-13. |
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