Abstract
Rates of methane emission associated with Florida
Typha domingensis Pers. and
Typha latifolia L. peaked in the early daylight hours and were two to four times higher than the relatively constant rates observed in the afternoon and night. Factors associated with methane emission peaks were increasing solar illumination which drives pressurized bulk flow ventilation in
T. domingensis and
T. latifolia, opening of stomata, and decreasing concentrations of methane within plant stems.
Cladium jamaicense Crantz, which employs diffusive gas exchange, did not exhibit diurnal variations in methane emission rates although stomatal conductance varied diurnally.
Within the Florida Everglades methane emission rates were higher in
T. domingensis areas (143±19 mg CH
4 m
−2 day
−1) than in
C. jamaicense areas (45±15 mg CH
4 m
−2 day
−1). These elevated rates were related to the higher above ground biomass and production in
T. domingensis areas relative to
C. jamaicense, which suggests that quantitative differences in plant biomass and production rather than qualitative differences between these plant species may control methane emissions. Methane emission was 2.7±1.4% of net daily ecosystem production (NEP) in a
T. domingensis area and 14±5.8% and 3.4±4.2% of NEP in two
C. jamaicense areas.
