【摘要】 为探究不同类型湖库沉积物有效态磷对富营养化的指示意义及适用范围,选取了12个不同水深、不同换水周期的湖泊和水库进行4季度的水样、沉积物样品采集,以SMT分级方法提取的氢氧化钠磷(Na OH-P)作为沉积物有效态磷,分析了湖库中沉积物和水相磷含量之间的关系.结果表明,12个湖库的沉积物和水相磷含量差别大,沉积物Na OH-P含量范围为86～584 mg·kg-1(均值263 mg·kg-1),总磷含量225～760 mg·kg-1(均值502 mg·kg-1);水体总磷含量范围为0. 02～0. 35mg·L-1(均值0. 11 mg·L-1); 12个湖库的水体叶绿素a含量差异也很大,分布范围为3～349μg·L-1(均值51μg·L-1);沉积物与对应的水相各形态磷含量之间的相关分析发现,沉积物有效态磷与水相磷含量之间的相关性高于沉积物总磷,Na OHP比总磷能更好地反映湖库的富营养化状态,然而只有在换水慢的浅水湖库中,这种沉积物Na OH-P与水相磷的相关性才达到显著水平,表明"换水周期"和"水体深度"是影响沉积物Na OH-P与水相磷含量相关关系的两个关键因子:在换水快或是深水的湖库中,即使沉积物有效态磷含量较高,但是受多种因素影响,沉积物Na OH-P与水相磷含量的相关关系可能并不显著,而在换水慢的浅水湖库中,沉积物作为源和汇频繁与水体磷进行交换,尤其是在夏季藻类暴发时期,对水相磷升高贡献大,成为该类水体富营养化问题易发生、难治理的潜在缓冲因子.更多还原

【Abstract】 Twelve lakes and reservoirs with different water depths and different water residence times were studied to identify the applicability of bioavailable phosphorus of sediments in indicating trophic levels. Water and sediment samples were collected in these12 lakes and reservoirs to analyze the relationship of nutrient levels between the sediment and the water column. Sodium hydroxide extracted phosphorus( Na OH-P) determined using the SMT classification method is defined as the bioavailable phosphorus of sediment.The results showed that total phosphorus levels in sediments in different lakes and reservoirs ranged from 225 to 760 mg·kg-1( mean value 502 mg·kg-1); the Na OH-P levels in sediments ranged from 86 to 584 mg·kg-1( mean value 263 mg·kg-1); the total phosphorus concentrations in the water was 0. 02-0. 35 mg·L-1( mean value 0. 11 mg·L-1),and the chlorophyll a concentrations in the water were 3-349 μg·L-1( mean value 51 μg·L-1). It was found that Na OH-P was more effective than total phosphorus in indicating the trophic status of the lakes and reservoirs. However,the Na OH-P levels were significantly related to the phosphorus concentrations in the water column only in shallow water with a long residence time. It was revealed that water residence time and water depth are two key factors that affect the relationship of the phosphorus content between the sediment and the water column. In deep waters or waters with short residence time,the Na OH-P content in the sediment hardly influenced the phosphorus concentration in the water columns,even at high levels. However,in shallow waters with long residence time,the sediment acted as both sources and sinks and frequently exchanged nutrients with the overlying water,especially during bloom periods in summer. Thus Na OH-P could be a potential risk of eutrophication in such waters.更多还原