Thursday, June 7, 2012

Trip to Mer Bleue

Recently I went hiking in Mer Bleue. Mer Bleue, for those not from the Ottawa area it is a large peat bog just outside of the city, that has several really great hiking trails and board walks through it. It is also an interesting place geologically and is internationally recognized as a wetland of importance.

Mer Bleue (Google Maps)
The most striking feature about Mer Bleue is the large peat bog, dominated by sphagnum moss and other bog plants like labrador tea. Ottawa is not actually an area one would associate with a peat bog such as this. Indeed, the ecosystem is a boreal habitat which is much more fitting in the Arctic as opposed to southern Ontario. The reason that Mer Bleue exists lies in the history of its formation.

Mer Bleue formed around 9,500 years ago at the end of the large continental galaciation that covered almost all of Canada. As the ice sheets melted a large glacial lake called Lake Champlain was formed in southern Ontario and deposited lots of lacustrine and marine clays in the area. However, once the weight of the glacier was removed from the area the land began to rebound upward. This is known as isostatic uplift. This uplift caused much of the lake to drain into the Atlantic Ocean. As the glacier continued to melt the river of water that resulted incised three deep channels into the clay, which is why it looks like Mer Bleue has three fingers. The raised areas between the fingers are actually sand dunes that were above water at time. As uplift continued the area was cut off from the early Ottawa River and became a small lake. Over the time this lake filled with bullrushes and other boreal plant species like sphagnum, which eventually took over the lake. This led to a build-up of organic matter within the lake and caused the oxygen levels to drop turning it into a bog.

Today the bog remains and is surrounded by a fantastic hardwood forest. It continues to be a popular tourist attraction and is a great place for a picnic. The bog is also the subject of research and several scientific papers have been published outlining its history, the carbon balance and hydrogeology of the bog. My visit was purely for pleasure, although I have been considering doing some research there too.

There are cool mushrooms in the hardwood forest on the dunes. Not sure what type this is. 

More cool mushrooms. Again, no idea what kind though.

The very sudden transition from boreal forest to sphagnum bog. 

Overlooking the sphagnum bog from the boardwalk
A green frog.
Thanks for reading and please feel free to comment.



  1. interesting post. It reminded me of two unusual wetlands in our region (Wyoming/South Dakota), also seemingly out-of-place and more at home to the north in the boreal zone. Both have concentrations of rare plants as well as unusual vegetation types, so I had to check -- sure enough, Mer Bleue has a bunch of rare plants as well:

    would be a great place to check out ... maybe one of these days :)

  2. I know the first mushroom is Amanita muscaria var. formosa.