首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Adverse Effects of Ammonia on Nitrification Process: the Case of Chinese Shallow Freshwater Lakes
Authors:Guoyuan Chen  Xiuyun Cao  Chunlei Song  Yiyong Zhou
Institution:1. Institute of Hydrobiology, The Chinese Academy of Sciences, 7 Donghu Nan Road, Wuhan, Hubei, 430072, China
2. Graduate School of the Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, China
Abstract:Nitrification is a process in which ammonia is oxidized to nitrite (NO 2 ? ) that is further oxidized to nitrate (NO 3 ? ). The relations between these two steps and ambient ammonia concentrations were studied in surface water of Chinese shallow lakes with different trophic status. For the oxidations of both ammonia and NO 2 ? , more eutrophic lakes generally showed significantly higher potential and actual rates, which was linked with excessive ammonia concentrations. Additionally, both potential and actual rates for ammonia oxidation were higher than those for NO 2 ? oxidation in the more eutrophic lakes, while in the lakes with lower trophic status, both potential and actual rates for ammonia oxidation were almost equivalent to those for NO 2 ? oxidation. This can be explained by the excessive unionized ammonia (NH3) concentration that inhibits nitrite-oxidizing bacteria in the more eutrophic lakes. The laboratory experiment with different ammonia concentrations, using the surface water in a eutrophic lake, showed that ammonia oxidation rates were proportional to the ammonia concentrations, but NO 2 ? oxidation rates did not increase in parallel. Furthermore, NO 2 ? oxidation was less associated with particles in natural water of the studied lakes. Without effective protection, it would be selectively inhibited by the excessive ammonia in hypereutrophic lakes, resulting in NO 2 ? accumulation. Shortly, the increased concentrations of ammonia cause a misbalance between the NO 2 ? -producing and the NO 2 ? -consuming processes, thereby exacerbating the lake eutrophication.
Keywords:
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号