淀山湖沉积物碳-氮垂直分布特征

近年来,经过一系列污染治理措施,淀山湖的营养水平持续下降,但每年仍有不同程度的蓝藻水华暴发,严重影响其作为水源地的安全性。为了进一步探讨淀山湖水质改善策略,本研究对淀山湖沉积物营养状况进行了调查研究,分析了淀山湖沉积物碳、氮分布特征及垂直变化规律,并用沉积物肥力评价了淀山湖沉积物营养程度。结果表明,淀山湖沉积物营养盐存在明显的富集作用,二十多年来沉积物碳、氮含量大幅上升,表层沉积物均属于重污染状态。空间分布上,沉积物营养盐北部高,南部低,北部样点大部分属于重污染状态,南部样点基本属于中污染状态。垂直分布上,受航道回淤与北部围网养殖影响,部分样点营养盐垂直分布规律不显著,其他样点均表现出随深度增加营养盐显著降低的趋势。除出水口D1样点外,淀山湖有机质与TN表现出显著的同源相关性,表明有机质是淀山湖内源负荷的主要来源。

Vertical Distribution Characteristics of TN and TOC in the Core Sediments of Dianshan Lake

Based on sampling work conducted in August of 2010,the temporal and spatial distribution characteristics of TN and TOC in the sediments of Dianshan Lake were analyzed.The results showed that the content of TN ranged from 0.46 to 2.18 mg/g and the content of TOC ranged from 2.3 to 14.9 mg/g.There were two vertical distribution characteristics of TN and TOC in the eight core sediments,which are the contents of TN and TOC decreases gradually with the increase of depth,the contents of TN and TOC increase gradually with the increase of depth or higher in the middle than in two ends.There was a significant positive correlation between TN and TOC in the sediments of the Dianshan Lake(r2=0.710 2).The highest organic index of the sediments in Dianshan Lake was 0.228,indicating that the sediments were very fertile.According to the organic indexes,the Dianshan Lake could be divided into two sections: light pollution area in south part and northeast part in north.