Carbon dioxide and methane exports from a southeastern floodplain swamp

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Ecological Monographs; (United States)

DOI:https://doi.org/10.2307/2937122· OSTI ID:6530772

Pulliam, W M ^[1]

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1. Univ. of Georgia, Athens (United States)

Patterns and rates of generation of CO[sub 2] and CH[sub 4] by aerobic and anaerobic soil respiration are a significant gap in knowledge of floodplain carbon dynamics. Gaseous and hydrologic exports of CO[sub 2] and CH[sub 4] from the forested floodplain of the Ogeechee River in Georgia, US, were studied from July 1987 to September 1989. CO[sub 2] emissions were highly seasonal, with largest rates during summer, and were strongly correlated with soil temperatures. Annual total CO[sub 2] emissions were similar in both years of the study, and averaged 919 g/m[sup 2]. The contribution of live root respiration to this total was estimated with in situ incubations of attached roots excavated from the soil. Over 55% of the total CO[sub 2] flux appeared to arise from live roots rather than mineralization of soil organic matter. Significant atmospheric CH[sub 4] fluxes were found only at flooded sites. CH[sub 4] emissions were highly variable, with high rates of release occurring irregularly during the warmer months. This effect is hypothesized to represent an interaction of the rates of oxygen consumption and replenishment in the soil. Over 90% of the total floodplain CH[sub 4] emissions came from the 30% of the floodplain that was most frequently inundated. Roughly half of the CH[sub 4] that entered the water column was consumed without reaching the atmosphere. Hydrologic exports of CO[sub 2] and CH[sub 4] via surface and groundwater were small, representing [approx]1-2% of total export for both species, and were much less important than fluvial exports of organic carbon. Overall, floodplain detrital carbon processing was dominated by aerobic respiration and gaseous CO[sub 2] export, although methanogenesis did constitute up to 20% of total soil respiration at some sites. 94 refs., 17 figs., 10 tabs.

• OSTI ID: 6530772
• Journal Information: Ecological Monographs; (United States), Vol. 63:1; ISSN 0012-9615
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CARBON DIOXIDE
BIOSYNTHESIS
METHANE
SWAMPS
DEGASSING
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
CARBON
CARBON CYCLE
FORESTS
GEORGIA
GREENHOUSE GASES
GROUND WATER
ORGANIC MATTER
RESPIRATION
ROOTS
SEASONAL VARIATIONS
SOILS
SURFACE WATERS
TEMPERATURE MEASUREMENT
ALKANES
AQUATIC ECOSYSTEMS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DEVELOPED COUNTRIES
ECOSYSTEMS
ELEMENTS
HYDROCARBONS
HYDROGEN COMPOUNDS
MATTER
NONMETALS
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SYNTHESIS
TERRESTRIAL ECOSYSTEMS
USA
VARIATIONS
WATER
WETLANDS
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)