Volcanogenic Sulfate and Fluoride deposition: Effects on organic and mineral soil gas fluxes and chemistry
This thesis focuses on the environmental effects of volcanic eruptions such as Eyjafjallajökull (2010) from which volcanic gases and ash particles can impact upon ecosystems located thousands of kilometres from the source. Currently very little is known about the impact of volcanic pollutants such a...
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| Format: | Thesis |
| Language: | English |
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University of York
2011
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| Online Access: | https://etheses.whiterose.ac.uk/2162/ https://etheses.whiterose.ac.uk/2162/1/NicMyersPhDThesis.pdf |
| Summary: | This thesis focuses on the environmental effects of volcanic eruptions such as Eyjafjallajökull (2010) from which volcanic gases and ash particles can impact upon ecosystems located thousands of kilometres from the source. Currently very little is known about the impact of volcanic pollutants such as SO4 and F on the carbon cycle. This study is a first step towards understanding the potential environmental impacts of volcanic eruptions on peatland and mineral soil C gas fluxes. Ombrotrophic peat mesocosms sampled from the Northern Peninne uplands, UK, were dosed over 20 weeks with concentrations of SO4-S (24.5 kg ha-1) and F (13.5 and 135 kg ha-1) simulating a distal Icelandic tephra deposit. Methane and CO2 gas fluxes were measured at regular intervals, but no significant differences were observed for any of the treatments when compared to the controls. This result contrasts with previous studies, which reported a suppression of CH4 emission with the addition of SO4. It can be explained if CH4 production has remained suppressed in the peat soils as a long-term consequence of heavy SO4 loadings in the Pennines area prior to the reduction of SO2 emissions from industrial sources in the 1970s. The mesocosm study results indicate that F deposition, at rates representative of tephra fallout does not interfere with C gas fluxes in peat soils, despite the well-established toxicity of F in the environment. However, F addition to a pristine peat soil in laboratory slurry experiments showed an increase in potential CH4 production rates thus further research is recommended. Addition of treatments containing high concentrations of F to peat mesocosms had a significant effect on soil solution chemistry. The addition of F increased the solubility of Al, Fe and acetate resulting in the accumulation of both species in solution near the peat surface. This build up of acetate, Al and Fe over the treatment period suggests that F breaks down organo-metallic compounds causing leaching of organic matter along with metal ions. This ... |
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