Control of the diurnal pattern of methane emission from emergent aquatic macrophytes by gas transport mechanisms

• Published in: Aquatic botany Vol. 54; no. 2; pp. 237 - 253
• Main Authors: Whiting, Gary J., Chanton, Jeffrey P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-1996
• Subjects: Diurnal pattern; Freshwater; Gas transport; Methane emission; Peltandra virginica; Throughflow; Typha latifolia; Methane emission; Gas transport; Throughflow; Peltandra virginica; Diurnal pattern; Typha latifolia
• ISSN: 0304-3770; 1879-1522
• DOI: 10.1016/0304-3770(96)01048-0

Methane emissions from
Typha latifolia L. showed a large mid-morning transient peak associated with rising light levels. This peak was also associated with a steep decline in lacunal CH
4 concentrations near the stem base. This pattern contrasted sharply with emissions from
Peltandra virginica (L.) Kunth that gradually rose to a peak in the mid-afternoon, corresponding to elevated air temperatures. Internal CH
4 concentrations within
P. virginica stems did not change significantly over the diurnal period. Stomatal conductance appeared to correlate directly with light levels in both plant types and were not associated with peak CH
4 emission events in either plant. These patterns are consistent with a convective throughflow and diffusive gas ventilation systems for
Typha and
Peltandra, respectively. Further effects of the convective throughflow in
T. latifolia were evident in the elevated CH
4 concentrations measured within brown leaves as contrasted to the near ambient levels measured within live green leaves. Experimental manipulation of elevated and reduced CO
2 levels in the atmosphere surrounding the plants and of light/dark periods suggested that stomatal aperture has little or no control of methane emissions from
T. latifolia.