|Peat mosses (Sphagnum spp.) are small, inconspicuous plants. They are phylogenetically old and primitive. They bear no flowers or blossoms that would attract our attention. You don't find them easily in Austria, and if you do, you most probably will get your feet wet. Is it worthwhile to dedicate a web site to this topic?
In my opinion, the answer is certainly "yes"! On this site, I would like to share my fascination about peat moss with nature lovers who may never have heard the term "Sphagnum", and try to provide concise information for them. I will also include one or the other more advanced detail that might be interesting to botanists, too.
Peat mosses are not only beautiful, if you look closely, they also have extraordinary characteristics that will be introduced on this page.
|Dead or Alive?|
|An intact peat moss plant is partly alive and partly dead. Its top part is alive; growth occurs exclusively at the plant's head. The bottom part of the plant has died from lack of light, and is already partially decayed. This unusual feature can be explained by the fact that peat mosses have neither roots nor a true vascular system of fluid transportation; nutrition of the living part of the plant is independent of its dead bottom section.|
Only the topmost few centimeters of the plant are above the water table. Further down, stem and leaves retain vast amounts of water, thus actively raising the water table. This extraordinary capacity of peat moss to raise the water table by trapping rainwater in spaces between stems and leaves is one of the prerequisites of bog formation. No bog can exist without peat moss!
|Nutrition: is Peat Moss Greedy?|
|Cell walls of peat moss bind large amounts of nutrients, much more than the plant needs for its own survival, leaving the nutrient level of the surrounding water barely above that of distilled water. The cell walls function as ion exchangers. They rapidly absorb cations, such as calcium and magnesium supplied by rainwater, and, in exchange, release hydrogen ions into the water. Because hydrogen ions render the water acidic, bog water is almost as sour as undiluted vinegar (pH=3-4). Thus, peat mosses create and maintain a nutrient-poor, acidic environment that fosters their own growth but is intolerable to all but a small variety of highly-specialized other plants.
|(1) If you have access to non-protected red peat moss, collect a few plants, and dry them.
(2) Submerge them in an alkaline solution (e.g., baking soda, dissolved in lukewarm water). The red color should fade. Depending on the original shade of red and on the strength of the base, the red color will change to pink, green, a bluish purple or even black.
(3) Rinse the plants briefly in water.
(4) Submerge them in an acidic solution (e.g., lemon juice or white vinegar). The original red color should reappear.
The pigment "sphagnorubin", a flavonoid contained in red peat moss, is a chemical indicator of acidity.
|Growth: Decimeters or Millimeters?|
|On the average, the height of peat moss increases by 10 centimeters during a summer season. The highest growth rate, up to more than 40 centimeters per summer, occurs in Sphagnum cuspidatum and S. subnitens, while S. rubellum may grow barely 4 centimeters per summer season. In winter, however, the weight of the snow blanket compresses the waterlogged parts of the plants so much that the yearly increase in height is reduced to approximately 1 millimeter. This unique growth feature can be explained by two other extraordinay characteristics of peat moss: (1) its water content is extremely high, and (2) the dead parts of the plants become only partially decomposed, thus retaining their morphological structures.|
The enormous yearly compression of Sphagnum material creates a zigzag banding below the living moss. Other plants have to adapt to this growth pattern in order to survive among peat moss.
|Peat is an accumulation of partially decayed plants. In contrast to completely decayed plant material in ground soil or swamp sediments, partially decayed plants in peat can be identified ever after thousands of years. Although some higher plants, such as sedges or reed, are also capable of producing certain amounts of peat, peat moss is the classical producer of high-quality peat, and only peat moss can accumulate peat deposits of up to 10 meters in depth.
Partial decay (humification) occurs under conditions of restricted microbial activity. Oxygen supply is sparse in bog water because of the low oxygen content of rainwater and the lack of surface water movement. In addition, proliferation of both aerobial and anaerobial bacteria is severely curbed by the high acidity of bog water.
Peat is an early stage in the transformation of vegetation into coal. Its carbon content is responsible for the dark brown color of peat (whereas bog water is tinted brown by tannic acids).
Flooded peat cutting
|Basics Morphology Life cycle Genetics Classification Bogs Links About me Home|