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Title: Acid rain links to CH4 emissions from wetlands.
Author: Gauci, Vincent.
ISNI:       0000 0001 2423 618X
Awarding Body: Open University
Current Institution: Open University
Date of Award: 2000
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A variety of approaches, spanning a range of spatial and temporal scales, were applied to the investigation of the effects of low dose SO/- deposition, at rates comparable to those experienced in acid rain impacted areas, on methane (CH4) emissions from natural wetlands. Over two years of experimental manipulation of S042- deposition to a peatland in northeast Scotland, CH4 emissions were suppressed by around 40%. There was no significant difference in suppression of CH4 flux within the sol- deposition range of 25-100 kg-S ha-1yr-l. In a similar short-term controlled environment SO/- manipulation experiment, the suppressive effect of SO/- was found to be independent of the simulated SO/- deposition rate within a range of 15-100 kg-S ha-1yr-l. The possibility that suppression of CH4 fluxes may have been the result of a 'salt effect' was ruled out. Both temperature and water table controlled the extent of CH4 flux suppression in acid rain impacted wetlands. Sulfate reduction potential in SO/- treatments were found to be 10 times larger than in control plots, suggesting that long-term suppression of CH4 fluxes is the result of the formation of an enlarged population of competitively superior sulfate reducing bacteria. SO/- concentrations were smaller in peat pore water from SO/- treatments than from controls. This is possibly the result of a stimulated SO/- reducing community scavenging available SO/-, thereby decreasing concentrations to below ambient levels. In northern peatlands (>50°) the effect of SO/- deposition at 1990 rates may have been sufficient to reduce emissions from these systems by around 15% annually. Globally, the effect of acid rain SO/- deposition may be sufficient to reduce CH4 emissions by as much as 22-28 Tg by 2030, which places this interaction within the same size category as many other components of the global CH4 budget that have received far greater attention.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Peatland; Methane Air Pollution Air Pollution Soil pollution Soil pollution Ecology