| 摘要: |
| 杭州西湖是一个小型浅水湖泊,底泥由上部藻骸腐泥和下部泥炭层构成,其显著特点是有机碳含量特别高,氮含量也相当高,而磷的富集程度相对较低。通过实验室和现场模拟研究,考察了pH值、温度、溶解氧、氧化还原电位及上覆水种类等环境因素对底泥释磷量和释磷速率的影响。上覆水pH值在6.5-7.0范围内底泥释磷量最低;在较高或较低pH值时,释磷量倍增。升高水温或降低上覆水溶解氧浓度均能加速释磷。实验室模拟西湖底泥最大释磷量为0.368μgP/g。夏季现场模拟平均释磷速率为1.02mg P/m2·d;由此估算底泥释磷量达1.346tP/a,相当于年平均外部入湖磷负荷的36.4%。底泥释磷对西湖富营养化起着不容忽视的影响。 |
| 关键词: 底泥 释磷 富营养化 西湖 |
| DOI：10.18307/1993.0110 |
| 分类号: |
| 基金项目:国家"七五"攻关项目(60-02-01-7-2) |
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| Phosphorus release from the sediments of west lake in hangzhou and its effects on lake eutrophication |
|
Han Weiming
|
|
Hangzhou Institute of Environmental Protection Science, Hangzhou 310007
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| Abstract: |
| West Lake in Hangzhou is a small shallow lake. Its surficial sedimentary stratum is composed of algae faulschlamm layer and peat layer, and is mainly characterized by high organic carbon content and extreme high nitrogen contents but by relatively low degree of phosphorus enrichment. A simulation study in laboratory and on the spot was conducted to determine the effects of various environmental parameters on the phosphorus release rate and the capacity from the sediments of West Lake in Hangzhou. Factors investigated in laboratory included pH, temperaturetdissolved oxygen, redox potential and overlying water type. The lowest release capacity was found when the pH was at the range of 6.5-7.0 for the overlying water. Raising the temperature or lowering oxygen concentrations in the overlying water may also accederate phosphorus release. The highest release capacity was found to be about 0.368 μg P/g in laboratory. The average release rate measured on the spot in summer was 1.02 mg P/m2·d. The calculated release capacity from the sediments of West Lake was 1.346tP/a, equivalent to 36.4% of the average annual external phosphorus loading. The internal loading is a major contributory factor in the continuing eutrophic states of the lake. |
| Key words: Sediments phosphorus release experiment eutrophication West Lake |
