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[1] Peatlands represent an important component of the global carbon cycle, storing 23 g C m À2 yr À1 . Peatland mining eliminates the carbon sink function of the peatland. In this paper we measure the total ecosystem respiration in a natural, 2 and 3 year (young) and 7 and 8 year (old) postcutover peatland near Sainte-Marguerite-Marie, Québec, during the summers of 1998 and 1999. Although the natural site was a source of CO 2 during the dry 1998 study season (138 g C m À2 ), CO 2 emissions were between 260 and 290% higher in the cutover sites (363 and 399 g C m À2 for young and old, respectively). Cutover site CO 2 emissions were only 88 and 112 g CO 2 -C m À2 at the young and old sites during the wet 1999 study season. Total ecosystem respiration was more dependent on the water table position than on changes in the thermal regime or the labile carbon of the peat in a dry summer, but the opposite was the case in a wet summer. CO 2 emissions increased with postharvest time regardless of a decrease in labile carbon, demonstrating that cutover peatlands are a large persistent source of atmospheric CO 2 . Direct measurement of the net ecosystem CO 2 exchange in cutover peatlands, as opposed to determining the loss of carbon from bulk density determinations, provides a better understanding of how peat drainage and harvesting operations affect the carbon balance in peatlands.

A review of freshwater wetland research in Canada was conducted to highlight the importance of these ecosystems and to identify wetland research needs. Both natural and constructed wetland systems are discussed. Natural wetlands are an important part of the Canadian landscape. They provide the habitat for a broad variety of flora and fauna and contribute significantly to the Canadian economy. It is estimated that the total value derived from consumptive and non-consumptive activities exceeds $10 billion annually. The past decades have witnessed the continued loss and degradation of wetlands in Canada. In spite of recent protection, Canadian wetlands remain threatened by anthropogenic activities. This review shows that more research on fate and transport of pollutants from urban and agricultural sources in wetland systems is needed to better protect the health and to assure the sustainability of wetlands in Canada. Furthermore, improved knowledge of hydrology and hydrogeochemistry of wetlands will assure more effective management of these ecosystems. Lastly, better understanding of the effect of climate change on wetlands will result in better protection of these important ecosystems. Constructed wetlands are man-made wetlands used to treat non-point source pollution. The wetland treatment technology capitalizes on the intrinsic water quality amelioration function of wetlands and is emerging as a cost-effective, environmentally friendly method of treating a variety of wastewaters. The use of wetland technology in Canada is, however, less common than in the U.S.A. A number of research needs has to be addressed before the wetland treatment technology can gain widespread acceptance in Canada. This includes research pertaining to cold weather performance, including more monitoring, research on design adaptation and investigation of the effects of constructed wetlands on wildlife.

[1] A simulation model flow in cutover peat systems (FLOCOPS) was developed to improve the current understanding of the hydrology of cutover peatlands and the water management programs designed to restore them. FLOCOPS considers temporal variability in peat bulk density, shrinkage character and q-Ψ (soil moisture-pressure head) relationships, volume changes due to compression, and changes to saturated hydraulic conductivity (K S ) and saturated volumetric soil moisture (q S ). FLOCOPS was evaluated by comparing simulated and observed 1998-1999 trends in elevation change (thickness of peat deposit), water table, q, and Ψ. FLOCOPS effectively represented observed trends in elevation change, q, and Ψ. A sensitivity analysis indicated that FLOCOPS was most sensitive to the retention, storage, and consolidation characteristics of the peat. Volume changes reduced hydrological variability, whereas low water retentivity and high water storage helped maintain high and stable q, Ψ, and water table position. The sensitivity of the peat system's hydrology to changes in pore structure suggests that minimizing changes to the peat's characteristic pore structure during extraction and subsequent abandonment of the peatland will result in significantly more favorable hydrological conditions for bog restoration.

This paper presents an overview of the hydrogeology and the freshwater resources of Sable Island, Nova Scotia. The role of the sand deposits, morphology and dynamics of the dune structures and systems, precipitation, and tidal influences are discussed. The distribution, quality, and importance of both surface water and groundwater resources of the island are also presented.  Fresh groundwater on the Island occurs in an unconfined sand lens aquifer. Studies to date on the hydrogeology of the island have shown highly variable rates of precipitation, both seasonally and annually, which in combination with the influence of shifting dune structures contribute to a dynamic freshwater /saltwater balance. Infiltration rates into the permeable aquifer system are greater than precipitation rates, precluding surface water flow.The chemical quality of water in the freshwater lens aquifer is generally good and meets the Guidelines for Canadian Drinking Water Quality. The aquifer is vulnerable to surface contamination, however, due to its shallow, unconfined nature, and any water supply wells are highly likely to be classified as being ‘under the direct influence of surface water’ (GUDI). Under these conditions a multi-barrier source water protection plan is considered essential for managing future public drinking water supplies on the Island.   Recommendations for future studies, including long-term monitoring of water level trends, are provided to support the sustainable use of groundwater on the Sable Island.