Methane and nitrous oxide concentration and emission flux of Yangtze Delta plain river net

• 来源期刊: 中国科学B辑（英文版）
• 年，卷（期）: 2009,（5）
• 页码范围: 652-661
• 页数: 10页
• 语种: 英文
• DOI: 10.1007/s11426-009-0024-0

摘要

Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmoI.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura-tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%).Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concen-tration had significant negative correlation with salinity and a significant positive correlation with ni-trate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bot-tom sediment that diffused through sediment-water interface into the water body and then into at-mosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water inter-face reached 778±59.8 and 236±03.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.