Publicaciones
Se encontró/encontraron 3 Publicaciones(s).
Kotowska, M. & Werner, F.A. (2013): Environmental controls over methane emissions from bromeliad phytotelmata: The role of phosphorus and nitrogen availability, temperature, and water content. GLOBAL BIOGEOCHEMICAL CYCLES 27, 1-8.
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DOI: 10.1002/2013GB004612
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Resumen:
Resumen:
Tank bromeliads are common epiphytic plants throughout neotropical forests that store
signi?cant amounts of water in phytotelmata (tanks) formed by highly modi?ed leafs.
Methanogenic archaea in these tanks have recently been identi?ed as a signi?cant source of
atmospheric methane. We address the effects of environmental drivers (temperature, tank
water content, sodium phosphate [P], and urea [N] addition) on methane production in
anaerobically incubated bromeliad slurry and emissions from intact bromeliad tanks in
montane Ecuador. N addition ? 1 mg g 1 had a signi?cantly positive effect on headspace
methane concentrations in incubation jars while P addition did not affect methane
production at any dosage (? 1 mg g 1 ). Tank bromeliads (Tillandsia complanata) cultivated
in situ showed signi?cantly increased ef?uxes of methane in response to the addition of
26 mg N addition per tank but not to lower dosage of N or any dosage of P (? 5.2 mg plant 1 ).
There was no signi?cant interaction between N and P addition. The brevity of the
stimulatory effect of N addition on plant methane ef?uxes (1–2 days) points at N
competition by other microorganisms or bromeliads. Methane ef?ux from plants closely
followed within-day temperature ?uctuations over 24 h cycles, yet the dependency of
temperature was not exponential as typical for terrestrial wetlands but instead linear. In
simulated drought, methane emission from bromeliad tanks was maintained with minimum
amounts of water and regained after a short lag phase of approximately 24 h. Our results
suggest that methanogens in bromeliads are primarily limited by N and that direct effects of
global change (increasing temperature and seasonality, remote fertilization) on bromeliad
methane emissions are of moderate scale.
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Keywords: |
nutrients |
gas emission |
NUMEX |
N-cycle |
nitrogen |
Gas exchange |
phosphorus |
nutrient manipulation |
nutrient limitation |
phosphorus availability |
nutrient cycle |
methane |
Wolf, K.; Flessa, H. & Veldkamp, E. (2011): Atmospheric methane uptake by tropical montane forest soils and the contribution of the organic layer. Biogeochemistry online, 15.
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DOI: 10.1007/s10533-011-9681-0
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Resumen:
Resumen:
Microbial oxidation in aerobic soils is the primary biotic sink for atmospheric methane (CH4), a powerful greenhouse gas. Although tropical forest soils are estimated to globally account for about 28% of annual soil CH4 consumption (6.2 Tg CH4 year−1), limited data are available on CH4 exchange from tropical montane forests. We present the results of an extensive study on CH4 exchange from tropical montane forest soils along an elevation gradient (1,000, 2,000, 3,000 m) at different topographic positions (lower slope, mid-slope, ridge position) in southern Ecuador. All soils were net atmospheric CH4 sinks, with decreasing annual uptake rates from 5.9 kg CH4?C ha−1 year−1 at 1,000 m to 0.6 kg CH4?C ha−1 year−1 at 3,000 m. Topography had no effect on soil atmospheric CH4 uptake. We detected some unexpected factors controlling net methane fluxes: positive correlations between CH4 uptake rates, mineral nitrogen content of the mineral soil and with CO2 emissions indicated that the largest CH4 uptake corresponded with favorable conditions for microbial activity. Furthermore, we found indications that CH4 uptake was N limited instead of inhibited by NH4 +. Finally, we showed that in contrast to temperate regions, substantial high affinity methane oxidation occurred in the thick organic layers which can influence the CH4 budget of these tropical montane forest soils. Inclusion of elevation as a co-variable will improve regional estimates of methane exchange in these tropical montane forests.
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Keywords: |
altitudinal gradient |
organic layer |
methane |
carbon dioxide |
Martinson, G.; Werner, F.A.; Scherber, C.; Conrad, R.; Corre, M.; Flessa, H.; Wolf, K.; Klose, M.; Gradstein, S.R. & Veldkamp, E. (2010): Methane emissions from tank bromeliads in neotropical forests. Nature Geoscience 2010(3), 766-769.