thumb|Mer Bleue Bog has a very popular autumn trail
Mer Bleue Bog is a protected area in Gloucester, Ontario, an eastern suburb of Ottawa in Eastern Ontario, Canada. Its main feature is a sphagnum bog that is situated in an ancient channel of the Ottawa River and is a remarkable boreal-like ecosystem normally not found this far south. Stunted black spruce, tamarack, bog rosemary, blueberry, and cottongrass are some of the unusual species that have adapted to the acidic waters of the bog.
The area provides habitat for many species, including beaver, muskrat, waterfowl, and the rare spotted turtle (Clemmys guttata). A 1.2 km (¾ mile) boardwalk allows visitors to explore a section of the bog. There are hiking trails that follow raised areas along the edges of the bog and cross-country skiing trails for use in winter. The conservation area is managed by the National Capital Commission.
The value of this unique wetland was not always recognized. During World War II, the Royal Canadian Air Force used this area for bombing practice. Now, this area has been designated as a Ramsar site, a Wetland of International Significance under the Ramsar Convention since October 1995, and an Area of Natural and Scientific Interest since 2011.
The name "Mer Bleue" (French, meaning "blue sea") is thought to describe the bog's appearance when it is covered in morning fog.
History
Europeans began farming in the area surrounding the bog in the 1830s. Active exploitation of the bog itself occurred from the 1870 to the early 20th century and included activities such as logging, hunting, blueberry picking, farming, peat extraction, development for transportation/utility corridors, recreation, and scientific investigations.
In the mid-1950s, the federal government of Canada expropriated the farmland, making it part of Ottawa's Greenbelt. Today, the bog is reserved mainly for recreational and scientific purposes.
Physical features
Mer Bleue is located in the western end of the southern melt water channel of the post-glacial Ottawa River (whereas the Alfred Bog formed at the eastern end of this channel). This channel was eroded into the floor of the Champlain Sea, which invaded the Ottawa Valley some 12 000 years ago. Bedrock topography consists of two north north-east/south south-west trending ridges. Surficial material consists of some glacial till, thick marine clay, and freshwater and deltaic deposits grading from coarse sand to clay. Peat deposits in the bog proper are up to thick.
There are two sand ridges that extend from the west towards the center of the conservation area. These two parallel ridges divide the bog in three sections. The northern ridge (Dolman Ridge) used to have farms, which were expropriated in 1958 and subsequently removed, while the southern ridge (Borthwick Ridge) continues to have a few farms on it and provides access to the visitor boardwalk.
The hydrological features at this site are most unusual. Being a domed bog, water enters the bog mainly from natural precipitation creating oligotrophic conditions. The periphery of the bog is encircled by a mineral-enriched lagg that maintains a base water level for the bog. Drainage is poor due to underlying clay deposits as well as numerous beaver dams. Water eventually drains slowly both westward into Greens Creek and eastward into Bear Brook. However, water levels remain at or near the surface of the bog for most of the year. Saline ground-water sources are found under the organic overburden. A number of artificial ditches were dug in the bog for land reclamation or drainage of adjacent lands, however, most are no longer functioning efficiently due to the many beaver impoundments and gradual sedimentation that has occurred along their lengths.
- Beech-maple forests (upland tolerant deciduous forest) rare in Ottawa-Carleton region
- Swampy forests of maple, cedar, and hemlock (lowland tolerant forests) are regionally significant
- Black spruce-larch forests (lowland intolerant coniferous forests), rare in the Ottawa district
- Open bog, low-shrub bog, and treed bog are highly significant within an Ottawa District and Southern Ontario context
- Bog pool is regionally significant
Nationally significant flora
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See also
- Greenbelt (Ottawa)
- List of Ramsar wetlands of international importance