Spatial and seasonal variation of methane emission from an Amazon floodplain lake

Wassmann, R.; Thein, U. G.

doi:10.1080/05384680.1996.11904079

Cited by 7 publications

(6 citation statements)

References 4 publications

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“…The lower values obtained in this study may be because of lower productivity. However, the results were within the range of ef¯uxes for southern oodplains (Pulliam & Meyer, 1992; Wassman & Thein, 1996;Boon et al, 1997;Otter & Scholes, 2000). The seasonal ef¯uxes in this study remained lower than those measured in southern areas, partly because the warm period is much shorter.…”

Section: Discussionsupporting

confidence: 59%

“…The ef¯uxes increased at a maximum by a factor of seven during the¯ood. It has been shown in several studies that periodically¯ooded, but otherwise rather dry, sites can act as CH 4 sources (Wassmann & Thein, 1996;Burke et al, 1999). The maximum ef¯uxes in the temporarily¯ooded sedge fen and marsh were at the same level as those in constantly inundated similar sites.…”

Section: Discussionmentioning

confidence: 77%

“…It has been shown in several studies that periodically¯ooded, but otherwise rather dry, sites can act as CH 4 sources (Wassmann & Thein, 1996;Burke et al, 1999). It has been shown in several studies that periodically¯ooded, but otherwise rather dry, sites can act as CH 4 sources (Wassmann & Thein, 1996;Burke et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

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Effects of spring flood and water level draw‐down on methane dynamics in the littoral zone of boreal lakes

2001

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1. The annual dynamics of methane (CH4) in a temporarily flooded meadow, mire bank, lacustrine sedge fen, temporarily and continuously inundated sedge (Carex sp.) and reed (Phragmites australis) marshes were studied from June to November in the humic mesoeutrophic Lake Mekrijärvi and in eutrophicated parts of the mesotrophic Lake Heposelkä in the southern part of East Finland. The effects of water level and temperature on littoral CH4 fluxes were determined. Vegetation zonation along the moisture gradient, and associated CH4 fluxes, were evaluated. 2. The CH4 flux increased along the moisture gradient from –0.2 to 14.2 mg CH4 m–2 h–1, and was highest in the permanently inundated marshes. The duration of anoxia in the sediment caused differences in the CH4 flux. Estimated emissions for the period 1 June – 30 September in continuously inundated sparse reed and sedge marshes, drying sedge marsh, and lacustrine sedge fen were 13, 11 and 6 g CH4 m–2, respectively. 3. In continuously inundated vegetation, the fluxes were highest in late July/early August. The seasonal CH4 flux pattern suggested that the fluxes were regulated by the supply of organic matter during the course of the summer and the water level. In the temporarily flooded zone, the seasonal CH4 flux dynamics was greatly affected by changes in the lake water level, the fluxes being highest during the spring flood in early June.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 77%

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Effects of spring flood and water level draw‐down on methane dynamics in the littoral zone of boreal lakes

2001

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“…Methane emission rates from the central Amazon floodplain have been measured using chambers in a variety of habitats and during various stages in the seasonal flood cycle (Bartlett et al ., 1988, 1990; Crill et al ., 1988; Devol et al ., 1988, 1990, 1994; Wassmann et al ., 1992; Wassmann & Thein, 1994; Engle & Melack, 2000). Emission rates have also been measured for the mainstem Solimões/Amazon River channel (Richey et al ., 1988) and in the Jaú River floodplain within the Negro River basin (Rosenqvist et al ., 2002).…”

Section: Methodsmentioning

confidence: 99%

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

Mélack

Hess

Gastil

et al. 2004

Global Change Biology

246

248

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Wetlands of the Amazon River basin are globally significant sources of atmospheric methane. Satellite remote sensing (passive and active microwave) of the temporally varying extent of inundation and vegetation was combined with field measurements to calculate regional rates of methane emission for Amazonian wetlands. Monthly inundation areas for the fringing floodplains of the mainstem Solimõ es/Amazon River were derived from analysis of the 37 GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer from 1979 to 1987. L-band synthetic aperture radar data (Japanese Earth Resources Satellite-1) were used to determine inundation and wetland vegetation for the Amazon basin (o500 m elevation) at high (May-June 1996) and low water (October 1995). An extensive set of measurements of methane emission is available from the literature for the fringing floodplains of the central Amazon, segregated into open water, flooded forest and floating macrophyte habitats. Uncertainties in the regional emission rates were determined by Monte Carlo error analyses that combined error estimates for the measurements of emission and for calculations of inundation and habitat areas. The mainstem Solimõ es/Amazon floodplain (54-701W) emitted methane at a mean annual rate of 1.3 Tg C yr À1 , with a standard deviation (SD) of the mean of 0.3 Tg C yr À1 ; 67% of this range in uncertainty is owed to the range in rates of methane emission and 33% is owed to uncertainty in the areal estimates of inundation and vegetative cover. Methane emission from a 1.77 million square kilometers area in the central basin had a mean of 6.8 Tg C yr À1 with a SD of 1.3 Tg C yr À1 . If extrapolated to the whole basin below the 500 m contour, approximately 22 Tg C yr À1 is emitted; this mean flux has a greenhouse warming potential of about 0.5 Pg C as CO 2 . Improvement of these regional estimates will require many more field measurements of methane emission, further examination of remotely sensed data for types of wetlands not represented in the central basin, and process-based models of methane production and emission.

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“…The frequency at which sites are flooded largely depends on the location along the river and thus on the elevation. The effect of wetting and drying on CH 4 emission from ephemeral floodplain wetlands has been studied at different tropical rivers (Wassmann and Thein, 1996; Boon et al ., 1997; Smith et al ., 2000). However, there is hardly any information on the ecology and the diversity of microbes in such habitats, in particular on the ones involved in methane flux like the archaea.…”

Section: Introductionmentioning

confidence: 99%

Community analysis of methanogenic archaea within a riparian flooding gradient

Kemnitz¹,

Chin²,

Bodelier³

et al. 2004

Environmental Microbiology

101

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Anoxic soils in river floodplains (or riparian soils) are a source of methane emission. However, little is known about the ecology and community structure of archaeal methanogenic microbes, which are a crucial component of methane flux in those habitats. We studied the archaeal community in the vertical profile of four different sites along the River Waal in the Netherlands. These sites differ in their annual flooding regime ranging from never or seldom to permanently flooded. The archaeal community structure has been characterized by terminal restriction fragment length polymorphism (T-RFLP) and comparative sequence analysis of the archaeal SSU rRNA gene and the mcrA gene. The latter gene codes for the alpha-subunit of methyl-coenzyme M reductase. Additionally, the potential methanogenic activity was determined by incubation of soil slurries under anoxic conditions. The community composition differed only slightly with the depth of the soil (0-20 cm). However, the diversity of archaeal SSU rRNA genes increased with the frequency of flooding. Terminal restriction fragment length polymorphism analysis of mcrA gene amplicons confirmed the results concerning methanogenic archaea. In the never and rarely flooded soils, crenarchaeotal sequences were the dominant group. In the frequently and permanently flooded soils, Methanomicrobiaceae, Methanobacteriaceae, Methanosarcinaceae and the uncultured Rice Clusters IV and VI (Crenarchaeota) were detectable independently from duration of anoxic conditions. Methanosaetaceae, on the other hand, were only found in the permanently and frequently flooded soils under conditions where concentrations of acetate were < 30 microM. The results indicate that methanogens as well as other archaea occupy characteristic niches according to the flooding conditions in the field. Methanosaetaceae, in particular, seem to be adapted (or proliferate at) to low acetate concentrations.

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Spatial and seasonal variation of methane emission from an Amazon floodplain lake

Cited by 7 publications

References 4 publications

Effects of spring flood and water level draw‐down on methane dynamics in the littoral zone of boreal lakes

Effects of spring flood and water level draw‐down on methane dynamics in the littoral zone of boreal lakes

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

Community analysis of methanogenic archaea within a riparian flooding gradient

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