Characteristics and distribution of biodegradable compounds of surface sediments in Lake Chaohu

Abstract

富营养化湖泊的藻类残体大量沉降到湖底,其中易降解成分的降解和转化快速消耗底层水体中的溶解氧,极易造成水土界面缺氧,影响湖泊生态系统的健康.于2014年对巢湖12个样点的表层沉积物进行周年跟踪研究,分析样品中有机质来源、总有机碳(TOC)、蛋白质、总糖、总脂以及生物聚合物碳(BPC)等成分含量,揭示易降解有机质的成分特征及在巢湖的分布规律.研究表明:巢湖表层沉积物TOC含量较高,全湖样点平均含量达到1.24%.BPC含量占TOC含量的30.99%~60.48%,有机质中易降解成分含量较高,并且在冬季和夏季时在巢湖西北部湖区有明显累积;有机质及其中的生物易降解部分均主要集中在粒径4~8μm的表层沉积物上,在应用工程技术手段处理、降解表层沉积物中的过量有机质时,更应该关注粒径为4~8μm的沉积物颗粒.;In eutrophic lakes large amount of algae detritus fall down to the lake bottoms every year. Dissolved oxygen in water would be consumed rapidly by labile compositions during degradation and transformation of the organic detritus, which can easily cause water hypoxia, affecting the health of lake ecosystem. Throughout the 4 seasons of 2014, 12 sampling sites for collected from surface sediments in Lake Chaohu were chosen to study the biodegradable organic components. In order to study characteristics of the labile components within the detritus and the distribution in the lake, source of organic matter, TOC, PRT, CHO, LPD and BPC contents in the samples were analyzed. Results have shown that the content of organic matter of surface sediments in Lake Chaohu is high, the average content reached 1.24%. BPC content accounts for 30.99% to 60.48% of TOC. The biodegradable organic components were relatively high, which accumulated obviously in northwestern Chaohu in winter and summer. The organic matter and biodegradable parts of surface sediments mainly adsorbed on the particle size of 48μm, so that the particles ranged from 48μm should be concerned when we use engineering measures to deal with excess organic matter in surface sediments.