Faddan More Psalter used as a liner to stiffen the cover somewhat. Low oxygen levels in the bog provide unusual preservation conditions, and bogs were often used by Irish monks as hiding places for valuables in the face of Viking raids. In addition to low oxygen levels, sphagnum moss, of which the peat bog is composed, produces an antibiotic substance called sphagnan that binds with proteins on the surface of microorganisms, immobilising them. Its highly reactive carbonyl groups can alter chemicals and nutrients that would otherwise decompose organic matter. And above all the sphagnum moss causes organic material to undergo chemical changes itself
Moss in cities. Examples would be "Rhytidiadelphus squarrosus", a garden weed in Vancouver and Seattle areas; "Bryum argenteum", the cosmopolitan sidewalk moss, and "Ceratodon purpureus", red roof moss, another cosmopolitan species. A few species are wholly aquatic, such as "Fontinalis antipyretica", common water moss; and others such as "Sphagnum" inhabit bogs, marshes and very slow-moving waterways. Such aquatic or semi-aquatic mosses can greatly exceed the normal range of lengths seen in terrestrial mosses. Individual plants or more long are common in "Sphagnum" species for example. Wherever they occur, mosses require liquid water for at least part of the year to complete