湖泊沉积物氮磷形态分布特征及其释放模拟研究

Study on distribution characteristics and release modeling of nitrogen and phosphorus in lakes sediments

底泥再释放是导致湖泊富营养化的重要因素,分析沉积物中氮磷释放规律及影响因素对湖泊综合治理具有重要意义.以太湖三个代表性的采样点为例,考察了四个季节中沉积物的氮磷形态分布及其静态和动态释放规律,并建立湖底泥氮磷内源释放的模拟实验.结果表明,三个采样点的沉积物均以无机物为主,扰动强度和温度是影响沉积物氮磷动态释放的主要因素.在无动力扰动下,夏季和秋季,底泥会向上覆水中释放氨氮;而在春季和冬季,上覆水中氨氮下降趋势明显.在有动力扰动下,底泥在春季和冬季比夏季和秋季的氨氮的释放量大,更高的扰动强度和较高的温度更有利于氮磷营养盐的释放.

Nutrient release is an important factor leading to lake eutrophication.It is of great significance to analyze the nitrogen and phosphorus release rules and influencing factors in sediment for comprehensive lake management.Taking three representative sampling points in the Taihu Lake as examples,this study investigated the distribution of nitrogen and phosphorus forms in sediment and their static and dynamic release laws in four seasons,and simulated the endogenous release of nitrogen and phosphorus in sediment.The results show that the sediments at the three sampling points are maily inorganic.The intensity of disturbance and seasonal differences are important factors that affect the dynamic release of nitrogen and phosphorus in sediment.Without dynamic disturbance,during summer and autumn,sediment releases ammonia nitrogen and phosphate into the overlying water.In spring and winter,the downward trend of ammonia nitrogen in the overlying water is obvious.Under dynamic disturbance,the release of ammonia nitrogen in the sediment is greater in spring and winter than in summer and autumn.Higher disturbance intensity and higher temperature are more conducive to the release of nitrogen and phosphorus nutrients.