Data/hora: 02/06/2024 13:04:23

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	03/01/1996	
Data da última atualização: 	04/04/2017	
Autoria: 	HAMILTON, S. K.; SIPPEL, S. J.; MELACK, J. M.	
Título: 	Oxygen depletion and carbon dioxide and methane production in waters of the Pantanal wetland of Brazil.	
Ano de publicação: 	1995	
Fonte/Imprenta: 	Biogeochemistry, v.30, n.2, p.115-141, 1995.	
Idioma: 	Inglês	
Conteúdo: 	This study examines dissolved O2, CO2 and CH4 in waters of the Pantanal a vast savanna floodplain. Measurements are presented for 540 samples from throughout the region, ranging from areas of sheet flooding to sluggish marsh strams to the major rivers of the region. Dissolved O2 is often strongly depleted, particularly in waters filed with emergent vascular plants, which are the most extensive aquatic environment of the region. Median O2 concentrations were 35 uM for vegetated waters, 116 uM for the Paraguay River, 95 uM for tributary rivers, and 165 uM for open lakes (atmospheric equilibrium, 230-290 uM). Air-water diffusive fluxes were calculated from dissolved gas concentrations for representative vegetated floodplain waters, based on data collected over the course of an annual cycle. These fluxes reveal about twice as much CO2 evasion as can be accounted for by invasion of O2 (overall means in nmol cm-2s-1:O2 0.18, CO2 0.34 and CH4 0,017). Methanogenesis is estimated to account for ca.20% of the total heterotropic metabolism in the water column and sediments, with the remainder likely due mostly to aerobic respiration. Anaerobic respiration is limited by the low concentrations of alternate electron acceptors. We hypothesize that O2 transported through the stems of emergent plants is consumed in aerobic respiration by plant tissues or microorganisms, producing CO2 that preferentially dissolves into the water and thus explaining most of the excess CO2 evasion. This hyphotesis is supported by measurements of gases in submersed stems of emergent plants.	
Palavras-Chave: 	Aquatic plant; Decomposition; Sediment.	
Thesagro: 	Decomposição; Planta Aquatica; Sedimento.	
Thesaurus Nal: 	floodplains; Pantanal; wetlands.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (30123-1) - ADC - SP - PP - SP14673 -  - 14673 - DIS