BIOGENIC GASES (CH4, CO2 AND O2) DISTRIBUTION IN A RIVERINE WETLAND SYSTEM

Abstract

Analysis of the distribution of biogenic gases in the floodplain of the Mogi-Guaçu River (São Paulo, Brazil allowed for the establishment of a "redox hierarchy", in which the main channel is the most oxidizing environment, followed by Diogo Lake, with Infernão Lake having the most reducing conditions of the subsystems evaluated. Diogo Lake exports about 853.4 g C.m^-2.year^-1, of which, 14.6% is generated from methanogenesis and 36.7% by aerobic respiration. For Infernão Lake, these values were 2016 g C.m^-2.year^-1. 8% and 41.5%, respectively. Carbon export by these systems is predominantly in the form of CO" 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 Infernão Lake. Such patterns may result from the nature of the hydrological conditions, the action of the hydroperiod, and morphological characteristics of the environment.