Methane flux from the Amazon River floodplain: Emissions during rising water

Journal Article · Thu Sep 20 00:00:00 EDT 1990 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JD095iD10p16773· OSTI ID:5937231

Bartlett, K B; Crill, P M ^[1]; Bonassi, J A ^[2]; Richey, J E ^[3]; Harriss, R C ^[4]

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1. College of William and Mary, Williamsburg, VA (USA)
2. Universidade de Sao Paulo (Brazil)
3. Univ. of Washington, Seattle (USA)
4. Univ. of New Hampshire, Durham (USA) NASA Langley Research Center, Hampton, VA (USA)

During April and May of 1987, an extensive methane flux data set from Amazonian wetland habitats was collected during the wet season as river water levels were high and rising. This work extends measurements made in the dry season of 1985, when water levels were falling. A total of 284 flux measurements were made in the three primary floodplain environments of open-water lakes and channels, floating grass mats, and flooded forests, along approximately 1,500 km of the central floodplain. Emissions (means and standard errors) were 74 {plus minus} 14 mg CH{sub 4}/m{sup 2}/d (open water), 201 {plus minus} 35 mg CH{sub 4}/m{sup 2}/d (grass mats), and 126 {plus minus} 20 mg CH{sub 4}/m{sup 2}/d (flooded forests). These values were not significantly different from the majority of those from 1985, in part due to the high variability in flux seen at both times. Although ebullition was a significant component of methane emissions at both periods, the frequency of bubbling and its contribution to total flux was lower during the period of rising water than during falling water. A prominent diurnal pattern in atmospheric methane concentrations was observed, with minimum levels of about 1.75 ppm at midday and a maximum of 2.12 ppm at about midnight. Given the relatively small season changes observed in flux at the two stages of the rivers hydrographic curve, earlier estimates of regional methane flux remain largely unchanged. Revision of global estimates of wetland methane sources based on these tropical data and recently published figures for northern peatlands indicated that tropical wetlands may be more important than previously suggested, but that wetland sources overall remain at approximately 110 Tg/yr.

• OSTI ID: 5937231
• Journal Information: Journal of Geophysical Research; (USA), Vol. 95:D10; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BRAZIL
AIR POLLUTION
METHANE
ENVIRONMENTAL TRANSPORT
WETLANDS
DEGASSING
AMAZON RIVER
ATMOSPHERIC CHEMISTRY
DAILY VARIATIONS
ECOLOGICAL CONCENTRATION
EMISSION
FLOODS
FORESTS
GLOBAL ASPECTS
SEASONAL VARIATIONS
SURFACE WATERS
TROPOSPHERE
ALKANES
AQUATIC ECOSYSTEMS
CHEMISTRY
DEVELOPING COUNTRIES
DISASTERS
EARTH ATMOSPHERE
ECOSYSTEMS
HYDROCARBONS
LATIN AMERICA
MASS TRANSFER
ORGANIC COMPOUNDS
POLLUTION
RIVERS
SOUTH AMERICA
STREAMS
VARIATIONS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)