Data/hora: 04/06/2024 14:06:41

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	01/10/2004	
Data da última atualização: 	06/04/2017	
Autoria: 	HAMILTON, S. K.; SIPPEL, S. J.; MELACK, J. M.	
Afiliação: 	Department of Biological Sciences, University of California, Santa Barbara.	
Título: 	Dissolved oxygen, carbon dioxide, and methane in waters of the Pantanal wetland of Brazil.	
Ano de publicação: 	1993	
Fonte/Imprenta: 	American Geoghysical Union Fall Meeting, Dec.1993, San Francisco. Abstract... San Francisco: [s.n], 1993. não paginado.	
Idioma: 	Inglês	
Conteúdo: 	The Pantnal is a 140,000-km2 complex of riverine floodplains and marshes in the upper Paraguay River basin. Most surface waters are shallow and slowly flowing, often with luxuriant growths of emergent and floating vascular plants. The water column is typically well-mixed or stratified only diurnally. We have sampled representative aquatic environments. throughout the region during 16 months for analysis of dissolved O2 (polarographic sensor), dissolved CO2 (calculated from pH, Gran alkalinity, temperature, and major ions), and dissolved CH4 (gas chromatography). Despite contact with the atmosphere, the waters are characteristically strongly oxygen-depleted: the median of 453 samples was 26% of atmospheric equilibrium (saturation), and 118 of those samples were <10% saturation. CO2 was nearly always supersaturated with a median partial pressure of 7560 ppmv (N=194). Ch4 was highly supersaturated (median 692 ppmv, N=447). This consistent pattern of O2 depletion and CO2 and CH4 accumulation reveals that overall, biological metabolism beneath the water surface is strongly heterotrophic; most net photosynthesis occurs above the water surface or during the dry season. Most anaerobic decomposition of organic matter probably culminates in methanogenesis due to the relative scarcity of alternate electron acceptors to support anaerobic respiration: the median concentration of sulface was only 0.55 uM (N=186; ion chromatography), dissolved H2S was <0.5 uM (methylene blue method), and the sum of nitrate plus nitrite was <7 uM. We are continuing to investigate the roles of iron and manganese in supporting anaerobic respiration, which may be significant but are difficult to estimate due to the participation of particulate forms of these elements.	
Thesagro: 	Água; Dióxido de Carbono; Metano; Oxigênio.	
Thesaurus Nal: 	carbon dioxide; methane; oxygen; Pantanal; water.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (54110-1) - ADC - SP - PP - SP14077 -  - 14077 - DIS