An organic carbon budget for an Amazon floodplain lake

Mélack, John M.; Engle, Diana L.

doi:10.1080/03680770.2009.11923906

Cited by 26 publications

(37 citation statements)

References 10 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: 75%

“…Alternatively, if most of the CO 2 emissions from SSA river channels are derived from wetland C, the net balance would be nearly neutral as it is balanced by the atmospheric CO 2 fixation by the emerged vegetation, as shown in the Amazon lowland areas [11][12][13] . Untangling the relative contributions of wetland and upland C in sustaining CO 2 and CH 4 emissions from inland waters is essential to better understand the role of tropical inland waters in the global C cycle and related potential feedbacks on a warming climate.…”

Section: Implications For Understanding Global C Fluxesmentioning

confidence: 99%

“…The CO 2 emissions from inland waters have been traditionally interpreted as fuelled by organic C from upland terrestrial biomass 1,14 . In the Amazon basin, CO 2 emissions from floodplain lakes 11 and from river channels 12,13 have been attributed to organic and inorganic C from wetlands (flooded forest and macrophytes). Finally, recently recognized biases in computed CO 2 data traditionally used in inland water studies 15,16 highlight the requirement for careful data-quality checking and future emphasis on high-quality direct CO 2 measurements.…”

mentioning

confidence: 99%

“…In particular, there is a need to further understand the link between inland water GHG fluxes and catchment characteristics, in particular regarding their connectivity with upland terrestrial 9,10 and wetland [11][12][13] C production and stocks. The CO 2 emissions from inland waters have been traditionally interpreted as fuelled by organic C from upland terrestrial biomass 1,14 .…”

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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: 75%

Section: Implications For Understanding Global C Fluxesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Globally significant greenhouse-gas emissions from African inland waters

et al. 2015

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“…Basin-wide hydrologic and hydrodynamic modeling suggests that surface water accounts for most of the Amazon's total storage (56%), followed by soil water (27%) and ground water (8%) [3]. Therefore, the amount of water on the Amazon floodplains and wetlands and the amount exchanged with river channels become essential information for understanding large-scale flood propagation, sediment delivery and nutrient exchanges, and the emission of methane and carbon dioxide [4][5][6][7][8][9][10][11][12]. However, measuring storage and its flux using in situ stage recording devices is not effective because its water flow is complex and not bounded, as in typical channel flow.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Water Level Changes of Large-Scale Amazon Wetlands Using ALOS2 ScanSAR Differential Interferometry

et al. 2018

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Differential synthetic aperture radar (SAR) interferometry (DInSAR) has been successfully used to estimate water level changes (∂h/∂t) over wetlands and floodplains. Specifically, amongst ALOS PALSAR datasets, the fine-beam stripmap mode has been mostly implemented to estimate ∂h/∂t due to its availability of multitemporal images. However, the fine-beam observation mode provides limited swath coverage to study large floodplains and wetlands, such as the Amazon floodplains. Therefore, for the first time, this paper demonstrates that ALOS2 ScanSAR data can be used to estimate the large-scale ∂h/∂t in Amazon floodplains. The basic procedures and challenges of DInSAR processing with ALOS2 ScanSAR data are addressed and final ∂h/∂t maps are generated based on the Satellite with ARgos and ALtiKa (SARAL) altimetry's reference data. This study reveals that the local ∂h/∂t patterns of Amazon floodplains are spatially complex with highly interconnected floodplain channels, but the large-scale (with 350 km swath) ∂h/∂t patterns are simply characterized by river water flow directions.

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