Dinâmica dos fluxos de dióxido de carbono e metano em área de várzea e terra firme do estuário Amazônico

Abstract

Terrestrial ecosystems are important for the greenhouse gases exchange (GHG) between the surface and the atmosphere. The objective of this research was to investigate the annual dynamics of carbon dioxide (FCO2) and methane (FCH4) fluxes in different environments, in relation to floristic composition and environmental variables in a floodplain area of the Amazon estuary. The flux of greenhouse gases (GHG) was simultaneously measured in the terrestrial and aquatic environment, in a tidal cycle, during few days in the year. This study also included a seasonal comparison of GHG fluxes in açaí planted in an upland area compared to an açaí managed area in the floodplain of the Amazon estuary. The floodplain study was carried out in the Environmental Protection Area of Combú Island (APA Combú), Belém, Pará (Brazil), between 2019 and 2021. The study in the upland area was carried out in Santa Maria do Pará. The methodology to measure soil and water FCO2 and FCH4 consisted of closed dynamic chamber and floating chambers methodology, respectively. The Amazonian estuaries showed topographic variability reflected in the water table height, which influences the soil FCO2 and FCH4 dynamics. In the same way that increase in soil temperature contributed to CO2 emissions. Therefore, a possible increase in global temperature could favor CO2 fluxes in the Amazon estuary. The tidal influence in the stream has strong impacts on FCO2 and FCH4 of the water, which play a key role in the carbon cycle through the CO2 and CH4 exchange between water-atmosphere environments. Lowland soils dominated by açaí plantations are a source of CO2 and CH4. However, the advance of açaí plantations in upland is positive for the environmental benefit (CH4 sink).