Science

What is Burns Bog?

Burns Bog is a type of wetland called a raised bog. Wetlands are defined in Canada as “land that has the water table at, near, or above the land surface”. They are places where you would expect to find plants and animals that are adapted to a wet environment. There are five types of wetlands in the Canadian classification system: bog, fen, swamp, marsh, and shallow open water.
On the Pacific Coast of British Columbia, there are five different kinds of bogs:

• basin bogs,
• shore bogs and floating bogs,
• slope bogs (also called blanket bogs),
• flat bogs, and
• domed bogs (also called raised bogs)
  

A bog is a peatland, which is a special kind of wetland where at least 30 cm of peat (plant matter) has piled up because the very wet conditions have created an environment where decomposition is extremely slow. Raised bogs get their name from the fact that the peat has piled up so high that the ground surface becomes raised above the local groundwater table, and the bog becomes isolated so that the only water entering the bog comes from precipitation (rain, snow, and fog). Precipitation is low in nutrients and, consequently, so are bogs. Fens and swamps can also be peatlands, but they are still connected to the mineral-rich groundwater so they receive more minerals and nutrients than bogs.

At the edge of a raised bog is a transition zone, called the “lagg”, where the bog meets the surrounding mineral-rich uplands. The water in the lagg zone is a mix of the bog and mineral-rich waters, and so the chemistry of the lagg water is transitional between the low pH, low-nutrient water of the bog and the high pH, mineral-enriched water of the mineral soil outside the bog. Most of the original lagg of Burns Bog has been filled by agricultural and industrial uses, but some important pieces of the lagg still remain relatively intact.

Profile of a raised bog (NTS)

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