Peat moss

Photo: Blåmannen in Bergen, 2020. Even though peat moss can make hiking difficult in places, they are highly significant species in storing carbon dioxide

Sphagnum is a plant genus with almost 380 species, commonly known as peat moss. Accumulation of sphagnum can hold water up to 25 times their dry weight. The empty cells help to retain water in drier conditions and as they continue to grow they can spread over dry regions. Sponging of the water in this way creates large bogs.

10% of the land area in Norway are peat moss and bogs. A large percentage of the peat mosses are found in the northern permafrost areas, the northernmost being Svalbard, Norway. 

Walkway on a peat bog, Finland. Photo source: Geographical

In the bogs, a biological material can break down anaerobically (without oxygen) and that way it retains more carbon-dioxide than it releases.

According to Hans H. Stenøie, evolutionary biology professor in Norwegian University of Science and Technology, 'No plant genus is more important in carbon balance on Earth than peat mosses. Peat stores at least a third of all the carbon stored on land.' 

When these bogs are destroyed, they start to release carbon to the atmosphere. Peat bogs are one of the most threatened habitats in Europe.

References:
https://norwegianscitechnews.com/2015/05/peat-moss-the-bane-for-our-existence/
https://www.wikiwand.com/en/Sphagnum
https://wilderness-society.org/importance-of-peat-bogs-as-co2-storage/
https://geographical.co.uk/places/wetlands/item/1101-in-defence-of-bogs