Geo Facts

Peat bogs feeling the effects of climate change

Higher temperatures were found to cause water tables in bogs to drop and more peat to decompose.

It's increasingly clear that the effects of climate change will be felt - or are already being felt - in all corners of the globe, in all kinds of ecosystems.

It even appears in peat bogs. A study in Nature Geoscience suggests that northern bogs may lose a significant portion of their peat as global temperatures rise. Organic matter in the peat will decompose, releasing carbon into the atmosphere.

Ordinarily, peat bogs are a huge carbon sink. They consist of marsh grasses, trees and other organic matter that, because of the wet, oxygen-starved conditions, don't decay much. What's more, peat generally begets(produces) more peat: because it holds so much water and blocks drainage, as it accumulates, the water table rises, reducing decay even further.

This water table-peat interaction is what scientists call a positive feedback loop. Takeshi Ise of the Japan Agency for Marine-Earth Science and Technology and colleagues looked at what would happen to this process when environmental conditions change.

Using data from bogs in northern Manitoba, the researchers simulated the effects of warming by seven degrees Fahrenheit. They found that higher temperatures would in effect reverse the feedback loop: the water table would drop, causing more peat to dry and decompose. Over hundreds of years, their simulation suggests, 40 per cent of organic carbon could be lost from bogs where the peat layer is shallow, while in deep bogs, the losses would be as much as 86 per cent.

-The New York Times
 

What is a bog?

A bog or mire is defined as a wetland that accumulates acidic peat, a deposit of dead plant material - usually mosses, but also lichens in Arctic climates.

A requirement for bogs to occur is acidic water at the ground surface level. This could either happen from acidic ground water, or where water is derived entirely from precipitation (vapour), when they are termed ombrotrophic (rain-fed).

If you have seen a bog or mire, you would know that the water that flows out of one has a characteristic brown colour, from the peat tannins which have got dissolved in the water. You may think that bogs are just dirty pools of muddy water, but this is not so. They are very sensitive habitats which play a very important role in the balance of biodiversity.

Did you know that the last Friday of June is International Bog Day?