Biogenic gases in tropical floodplain river

Analysis of the distribution of biogenic gases in the floodplain of the Mogi-Guacu River (Sao Paulo, Brazil) enabled the establishment of a "redox hierarchy", in which the main channel was the most oxidizing environment, followed by Diogo Lake, with Infernao Lake having the most reducing conditions of the subsystems evaluated. Diogo Lake exported about 853.4 g C.m(-2) year(-1), of which, 14.6% was generated from methanogenesis and 36.7% by aerobic respiration. For Infernao Lake, these values were 2016 g C.m(-2) year(-1), 1.8% and 41.5%, respectively. Carbon export by these systems was predominantly in the form of CO2, which was responsible for the release of 728.78 g C.m(-2) year(-1) at Diogo Lake and 1979.72 g C.m(-2). year(-1) at Infernao Lake. Such patterns may result from the nature of the hydrological conditions, the action of the hydroperiod, and morphological characteristics of the environment.