Fluxo do CO2 proveniente da respiração do solo em áreas de floresta nativa da Amazônia / CO2 flux from soil respiration in areas of native Amazon forest

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Carbon dioxide is an important contributor to the greenhouse effect, and by extension, the global climate system as a whole; it is generated and consumed through the activities of terrestrial and aquatic microorganisms. Tropical forest CO2 fluxes at the soil-atmosphere interface depend on changes in the physical, chemical and biological characteristics of the soil surface. The objective of the present study is to investigate seasonal variability of CO2 fluxes from soil respiration in Amazonian native forest located in the municipalities of Sinop (MT), Caxiuanã (PA), Manaus (AM) e Santarém (PA) and to determine the effects of determining parameters such as temperature and soil moisture. The CO2 fluxes were measured using dynamic chambers during both dry and wet seasons at each site. As the concentration of the gas inside the chamber varies with time, samples were taken at given time intervals and fluxes then calculated using linear regression equations. The average values found for Sinop in the dry and wet seasons were 3.03 and 5.92 μmol.CO2 m-2s-1 respectively; for Caxiuanã, 5.07 μmol.CO2 m-2s-1 and 6.09 μmol.CO2 m-2s-1; for Manaus, 5.47 and 5.44 μmol.CO2 m-2s-1; and for Santarém, 5.64 μmol.CO2 m-2s-1 in the wet season and during the dry season and 6.09 μmol.CO2 m-2s-1. Our results showed that there was a seasonal variation of the CO2 flux. The results also showed that there was an influence of the seasonality in the dynamics of the soil CO2 flux, where the greater fluxes were obtained during the wet season, indicating that water availability and soil temperature were the main factors determining production. Litter samples had been collected and roots esteem the supply and influence it on the CO2 fluxs of in the soil, being these, ways of entrance of nutrients and mainly of carbon for the ground. For all the regions the biggest supplies had been found in the dry station.

ASSUNTO(S)

carbon cycle soil respiration temperatura do solo ciclo biogeoquímico variação sazonal amazônia floresta nativa floresta soil co2 flux amazon

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