This study uses life cycle analysis to examine the net greenhouse gas (GHG) emissions from the activities of the peat industry in Canada for the period 1990 to 2000. GHG accounting is undertaken for (1) land use change, (2) peat extraction and processing, (3) the transport of peat to market by truck, train and ship, and (4) the in situ decomposition of extracted peat. The emission estimates were based on results from GHG accounting models using data derived from scientific literature, government and industry statistics, and the responses to a questionnaire sent to Canada's peat establishments. The questionnaire, designed to obtain information on peat extraction methods, land and fuel use, as well as the transportation of peat, had a response rate representing 69% of Canada's total peat production in the year 2000. Results indicate that 540 600 tonnes of greenhouse gases were emitted in 1990 and 893 300 tonnes were emitted in the year 2000 (emission figures are measured in CO2 equivalents using a 100-year time horizon). Peat decomposition was by far the largest source of GHG emissions, averaging 70.6% of total emissions during the eleven-year period from 1990 to 2000. Greenhouse gases from land use change averaged 14.7%. An average of 10.4% of total emissions resulted from the transport of peat to market, while GHGs from extraction and processing averaged 4.3%. Predictions of the annual GHG emissions from the peat industry, assuming a "business as usual" context, were produced for the years 2001 to 2012. These figures were compared with those resulting from various greenhouse gas reduction scenarios.

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Northern peatlands are an important long-term sink for atmospheric carbon dioxide (CO2) and a contemporary source of methane (CH4). Under contemporary climate and environmental change, including enhanced nutrient deposition through industrialization and commercial peat harvesting, the microbial environment in peat is altered. Microorganisms are responsible for the net production of greenhouse gases in these sites, although controls on microbial activity and microbial communities are poorly understood, limiting our ability to predict greenhouse gas emissions. The objective of this thesis was to determine the microbial role in peat decomposition and greenhouse gas fluxes in northern peatlands. Nutrient, carbon (C) substrate, and microbial-ecological controls on microbial activity under natural climate variability, increased nutrient deposition, and commercial harvesting and restoration were explored in detail. Environmental change effects were evaluated in relation to processes and temporal variability in pristine sites. / The natural temporal variability of decomposition, microbial biomass, and nitrogen (N) was characterized in the Mer Bleue bog near Ottawa, ON over two years. In a warmer, drier year, lower water table position corresponded to increased N availability, which was in turn linked to enhanced microbial CO2 production, consistent with patterns in ecosystem respiration measured at the site level. It was shown that microbial activity can play an important role in inter-annual climate driven ecosystem respiration and net ecosystem CO2 exchange. / Through field and laboratory nutrient fertilization experiments, it was shown that increased nitrogen (N) deposition altered the heterotrophic microbial community at Met Bleue and led to decreased decomposition rates after one year, despite increased total microbial biomass. After the second year of fertilization, however, decomposition rates were elevated, presumably a result of a concomitant shift in moss species and supply of more bioavailable plant material. Comparison of fertilizations in the presence and absence of vegetation indicated that in oligotrophic sites, vegetation mediated elevated nutrient effects on decomposition and that N cycling occurred largely in the organic forms. / Aerobic and anaerobic microbial activity, peat organic and nutrient chemistry, microbial biomass, and methanogen, CH4-oxidizing bacteria, bacteria, and archaea were characterized in two sets of pristine, actively harvested, harvested and abandoned, and harvested and restored peatlands in Quebec and New Brunswick.

No description available.