Regionalization of methane emissions in the Amazon Basin with microwave remote sensing

Mélack, John M.; Hess, Laura L.; Gastil, Mary; Forsberg, Bruce R.; Hamilton, Stephen K.; Lima, I.B.T.; Novo, Evlyn Márcia Leão de Moraes

doi:10.1111/j.1365-2486.2004.00763.x

Cited by 246 publications

(287 citation statements)

References 70 publications

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“…Similarly, a relationship between CH 4 , p CO 2 and %O 2 with wetland fraction was also found across river systems (Fig. 4), consistent with findings in the Amazon basin, where CO 2 emissions from wetland lakes and river channels have been attributed to organic C from wetlands [11][12][13] that also sustain intense CH 4 evasion 17 .…”

Section: Processes Underlying Ghg Dynamicssupporting

confidence: 84%

“…Second, our estimates do not account for extensive tropical wetlands, which in the Amazon are known to show CH 4 fluxes two orders of magnitude higher than river channels 17 . The Congolese 'Cuvette Centrale' , with a flooded surface area of 360×10 3 km 2 (ref.…”

Section: Regional and Global Significance Of Ghg Fluxesmentioning

confidence: 99%

“…We propose that our emission estimates of CO 2 and CH 4 from SSA rivers may be conservative for two reasons. First, the FCH 4 values correspond only to diffusive emissions and do not account for CH 4 ebullition, which can be highly significant in tropical aquatic environments [17][18][19] . Based on floating chamber flux measurements in the Congo and Zambezi rivers (n = 68), we found CH 4 ebullition rates to be on average 0.25 times the diffusive CH 4 flux ( Supplementary Fig.…”

Section: Regional and Global Significance Of Ghg Fluxesmentioning

confidence: 99%

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Globally significant greenhouse-gas emissions from African inland waters

et al. 2015

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Carbon dioxide emissions to the atmosphere from inland waters-streams, rivers, lakes and reservoirs-are nearly equivalent to ocean and land sinks globally. Inland waters can be an important source of methane and nitrous oxide emissions as well, but emissions are poorly quantified, especially in Africa. Here we report dissolved carbon dioxide, methane and nitrous oxide concentrations from 12 rivers in sub-Saharan Africa, including seasonally resolved sampling at 39 sites, acquired between 2006 and 2014. Fluxes were calculated from published gas transfer velocities, and upscaled to the area of all sub-Saharan African rivers using available spatial data sets. Carbon dioxide-equivalent emissions from river channels alone were about 0.4 Pg carbon per year, equivalent to two-thirds of the overall net carbon land sink previously reported for Africa. Including emissions from wetlands of the Congo river increases the total carbon dioxide-equivalent greenhouse-gas emissions to about 0.9 Pg carbon per year, equivalent to about one quarter of the global ocean and terrestrial combined carbon sink. Riverine carbon dioxide and methane emissions increase with wetland extent and upland biomass. We therefore suggest that future changes in wetland and upland cover could strongly a ect greenhouse-gas emissions from African inland waters.C limate predictions necessitate a full and robust account of natural and anthropogenic greenhouse-gas (GHG) fluxes, especially for CO 2 (refs 1-3), CH 4 (ref. 4) and N 2 O (ref. 5), which together accounted for 94% of the anthropogenic global radiative forcing by well-mixed GHGs in 2011 relative to 1750 (ref. 6). Inland waters (streams, rivers, lakes and reservoirs) are increasingly recognized as important sources of GHGs to the atmosphere, with global CO 2 and CH 4 emissions estimated at 2.1 PgC yr −1 (ref.3) and 0.7 PgC yr −1 (CO 2 -equivalents; CO 2 e) (ref. 4) (1 Pg = 10 15 g), respectively. Considering that the oceanic and land carbon (C) sinks correspond to ∼1.5 and ∼2.0 PgC yr −1 (ref. 7), respectively, the GHG flux from inland waters is significant in the global C budget.In a recent global compilation of inland CO 2 data 3 , <20 data points (out of 6,708, that is, <0.3%) represented African inland waters (with the exception of South Africa, which has been densely sampled), even though they account for ∼12% of both global freshwater discharge 8 and riverine surface area 3 , and include some of the largest rivers and lakes in the world. Equally for the global CH 4 database, there is a strong under-representation of tropical inland waters, whereby a recent synthesis 4 resorted to extrapolating CH 4 fluxes from temperate rivers.The prevailing large uncertainty involved in GHG flux estimates for inland waters, essentially due to the paucity of available data, is coupled to a poor understanding of underlying processes, both of which preclude gauging of future fluxes in response to human pressures. In particular, there is a need to further understand the link between inland water GHG fluxes and ...

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Section: Processes Underlying Ghg Dynamicssupporting

confidence: 84%

Section: Regional and Global Significance Of Ghg Fluxesmentioning

confidence: 99%

Section: Regional and Global Significance Of Ghg Fluxesmentioning

confidence: 99%

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Globally significant greenhouse-gas emissions from African inland waters

et al. 2015

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“…Uma cobertura também bastante dinâmica é formada pelas áreas de solo exposto e campos não inundados que são ocupados durante o período de inundação por água aberta ou por plantas flutuantes. O conhecimento dessa dinâmica é fundamental para os estudos realizados por Melack et al (2003) visando à determinação dos fluxos de CH 4 dos ecossistemas alagáveis da Amazônia, uma vez que trabalhos anteriores (Devol et al, 1990) já demonstraram a interferência dos diferentes tipos de cobertura sobre a magnitude das emissões.…”

Section: Técnicas Avançadas De Sensoriamento Remoto Aplicadas Ao Estuunclassified

Técnicas avançadas de sensoriamento remoto aplicadas ao estudo de mudanças climáticas e ao funcionamento dos ecossistemas amazônicos

et al. 2005

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RESUMOEste artigo se propõe a apresentar exemplos de questões científicas que puderam ser respondidas no contexto do Projeto LBA (Large Sale Biosphere-Atmosphere Experiment in Amazonia) graças à contribuição de informações derivadas de sensoriamento remoto. Os métodos de sensoriamento remoto permitem integrar informações sobre os vários processos físicos e biológicos em diferentes escalas de tempo e espaço. Nesse artigo, são enfatizados aqueles avanços de conhecimento que jamais seriam alcançados sem a concorrência da informação derivada de sensoriamento. PALAVRAS -CHAVE

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“…devido à sua extensa área, este sistema hidrográfico representa importante papel na modulação do clima e dos ciclos biogeoquímicos regionais e globais (Mayorga & aufdenkampe, 2002). devido à topografia plana (que não chega a exceder os 100 m acima do nível do mar), solos pouco drenados, grande variação sazonal da precipitação e altos níveis de pluviosidade (Junk, 1997), aproximadamente 17% da Bacia amazônica é permanente ou temporariamente inundada (Melack et al, 2004).…”

Section: Introductionunclassified

Reconstituição paleoambiental do Lago Santa Ninha, Várzea do Lago Grande de Curuai, Pará, Brasil

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Turcq³

2009

Acta Amaz.

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RESUMOeste estudo teve por objetivo reconstituir as mudanças paleoambientais e paleohidrológicas no baixo amazonas. um testemunho de sedimento foi coletado no Lago Santa Ninha, na várzea do Lago Grande de curuai, localizada na margem direita do rio amazonas a aproximadamente 850 km da foz. o teor de água, a granulometria, as datações com carbono 14, os conteúdos de carbono orgânico e nitrogênio total e o isótopo estável do carbono (δ 13 c) foram utilizados para determinar os processos sedimentares a que o meio esteve submetido. o testemunho estudado possui 270 cm de comprimento que corresponde a um período de 5600 anos cal aP. este estudo colocou em evidência diferentes ambientes sedimentares: na base do testemunho até 4900 anos cal aP há uma vegetação inundada que foi gradualmente substituida por bancos de gramíneas e por uma planicie com secas sazonais em 4000 anos cal aP até alcançar, desde 600 anos aP as condições atuais deste lago. estas alterações podem ter ocorrido em decorrência de mudanças no ciclo hidrológico do rio amazonas que, por sua vez, também são reflexos de alterações climáticas.PALAVRAS-CHAVES: paleohidrologia, paleoambientes, amazônia, várzeas. Paleoenvironmental reconstruction of an Amazon floodplain lake, Lago Santa Ninha, Varzea do Lago Grande de Curuai, Pará, BrasilABSTRACT Physical, chemical and geochemical characteristics of lacustrine sediments were studied to reconstruct paleohydrologyical control on sedimentation in an amazonian floodplain. a core was collected at the Lago Grande de curuai floodplain, in the Santa Ninha Lake, located on the right margin of the amazon river at 850 km of the estuary. Water content, granulometry, radiocarbon dating, organic carbon, nitrogen content and δ 13 c were used to characterize the sedimentary processes. The core is 270 cm-long which corresponds to 5600 cal years BP. The core points out different sedimentary environments: flooded vegetation at the base of the core till 4900 cal years BP is substituted by grass banks changing to a floodplain encompassing prolonged annual dryness at 4000 cal years BP. Since 600 cal years BP, the present day Varzea Lake, permanently over flooded, has been installed.

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Regionalization of methane emissions in the Amazon Basin with microwave remote sensing

Cited by 246 publications

References 70 publications

Globally significant greenhouse-gas emissions from African inland waters

Globally significant greenhouse-gas emissions from African inland waters

Técnicas avançadas de sensoriamento remoto aplicadas ao estudo de mudanças climáticas e ao funcionamento dos ecossistemas amazônicos

Reconstituição paleoambiental do Lago Santa Ninha, Várzea do Lago Grande de Curuai, Pará, Brasil

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