绿潮硬毛藻衰亡分解过程中营养盐的释放规律

The research on nutrients release during the decomposition of Chaetomorpha sp.

通过室内模拟,研究了不同环境条件下绿潮硬毛藻的分解速率,以及死亡藻体内营养盐的释放规律,以阐明硬毛藻大量衰亡对天鹅湖水质的潜在影响。结果显示,温度对硬毛藻分解速率的影响显著（P〈0.01）,高温（30℃）可促进藻体的分解,而沉积物和营养盐水平对分解的影响相对较小。在试验前期（0～7 d）,硬毛藻的分解速率较大,藻体中的P向水体大量释放;而N的释放量较低,并呈持续释放的趋势。P释放率最高可达91.63%,而N仅为73.01%。温度、沉积物对藻体N、P释放的影响显著（P〈0.01）,各因子对藻体P释放的影响效应表现为：温度〉沉积物〉营养盐水平;N释放为：沉积物〉温度〉营养盐水平。高温条件下,死亡藻体的N、P释放率均较高。因此,在温度较高的夏末秋初,应及时清理湖区中的死亡藻体,以免导致水质恶化,造成二次污染。

The decomposition rate of Chaetomorpha sp. at different conditions and the release discipline of nutrients from the algal issue were studied in laboratory. The aim of this study was to explain the potential influence of Chaetomorpha decomposition on water quality in Swan Lake. The results showed that the decomposition rate of Chaetomorpha was significantly influenced by temperature（ P〈0. 01）,and high temperature（ 30℃） could promote the decomposition. However,the effects of sediment and nutrient level on algal decomposition were relatively small. During the early decomposition（ 0 ～ 7 d）,the decomposition rate was large and a lot of phosphorus in algal issue was released into the water,while the nitrogen release was slow and last for a long time. The highest release rate of phosphorus reached to91. 63%,while the highest nitrogen release rate just reached to 73. 01%. The release rate of nitrogen and phosphorus was obviously influenced by temperature and sediments（ P〈0. 01）. The effects of different factors on phosphorus release followed the order of temperature sediment nutrient level,while that of nitrogen release was sediment temperature nutrient level. The release rate of nitrogen and phosphorus was both higher on high temperature conditions. Therefore,the dying Chaetomorpha should be removed in time to avoid the deterioration of water quality and secondary pollution in the early autumn.