Methane emissions to the troposphere from the Amazon floodplain

摘要: Methane emissions to the troposphere from Amazon River floodplain have been determined. In total, 94 individual flux measurements were made along a 1,700-km stretch of river during early falling water period flood cycle (July–August 1985). The overall average rate CH4 emission wetlands was 390 mg m−2 d−1. Water surfaces covered by aquatic macrophytes had highest emissions, 590 d−1, while flooded forests 110 d−1 and open lake areas averaged 120 Ebullition dominant mechanism emission, accounting for 85% total. Surface dissolved oxygen always undersaturated, CO2 concentrations significantly supersaturated with respect atmospheric equilibrium. highly supersaturated, averaging 6.4 μM. δ13C varied −42‰ −73‰ an apparent trend toward heavier values downstream. Extrapolation entire results in estimated annual 10 Tg yr−1 indicates importance area global cycle.