Soil CO2 Efflux Dynamics in the Northern Pantanal of Mato Grosso, Brazil during the Wet-Dry Season Transition

Wednesday, 17 December 2014
Osvaldo Borges Pinto-Jr1, George L Vourlitis2, Cloe Suzanne Hentz3, Paulo Henrique Zanella de Arruda1, Franciele Bonfiglio Santanna1, Marizeth de França Dias4, Carlo Ralph de Musis4 and Jose de Souza Nogueira1, (1)UFMT Federal University of Mato Grosso, Cuiabá, Brazil, (2)California State University San Marcos, Biology, San Marcos, CA, United States, (3)California State University San Marcos, San Diego, CA, United States, (4)Unic - University of Cuiaba, environmental science, Cuiabá, Brazil
The roles of tropical wetlands in the global carbon (C) cycle are still poorly understood, especially in seasonally flooded forests that are expected to be important sinks for atmospheric CO2. We measured soil CO2 efflux during the wet-dry transition period in a seasonally flooded palm-dominated forest (locally known as Acorizal) to determine the effect of litter input and seasonal hydrology. Measurements were performed monthly as part of a field litter manipulation experiment consisting of three treatments (litter removal, litter addition, and control; n = 6 plots per treatment), and our research objectives were to determine how soil CO2 efflux varied as a function of (1) litter input, (2) root density, and (3) seasonal variation in soil water content. We found that litter addition significantly increased soil CO2 efflux, but there was no relationship between root density and soil CO2 efflux. Efflux was highest during the wet season and declined as soil water content declined. Our data demonstrate that variations in litter inputs and soil water content are important controls on soil CO2 efflux in seasonally flooded tropical forests.