Sphagnum

Sphagnum.flexuosum

Sphagnum cells

Red Sphagnum Closeup

Sphagnum Brown's Lake Bog

Schultz Sphagnum Peat Moss

Making sphagnum moss dressings, University of Toronto

Sphagnum is a genus of approximately 380 accepted species of mosses, commonly known as "peat moss". Accumulations of Sphagnum can store water, since both living and dead plants can hold large quantities of water inside their cells; plants may hold 16–26 times as much water as their dry weight, depending on the species. The genus is notable for its unique structure and has a distinct role in ecosystems where it is found, particularly in bogs, wetlands, and peatlands, where they are often dominant components of the vegetation.

Characteristics

Sphagnum mosses possess a two-part stem structure, with a spreading and a pendent branch on each stem node. The leaves of Sphagnum are spirally arranged, with dead cells (hyaline cells) helping in water retention and living chlorophyllose cells aiding in photosynthesis. This unique structure allows them to absorb water efficiently and maintain the high humidity environment that is crucial for bog and wetland ecosystems.

Ecology

Sphagnum plays a critical role in the formation of peat bogs by accumulating in layers, with the lower layers slowly decomposing under anaerobic conditions to form peat. This process is very slow, with peat accumulation rates typically ranging from 0.5 to 1 mm per year. The acidic and waterlogged conditions of Sphagnum-dominated ecosystems limit the decomposition of plant material, leading to the accumulation of organic matter.

Sphagnum mosses also contribute to the acidity of their environment by releasing hydrogen ions in exchange for nutrient cations from the surrounding water, further inhibiting the growth of other plant species and thus maintaining their dominance in peat bogs.

Distribution

Sphagnum species are distributed globally, with the highest diversity in the Northern Hemisphere. They can be found in a range of habitats from arctic tundra to tropical rainforests, but their primary habitat is peatlands, which are most extensive in the boreal forests of Canada, Russia, and Northern Europe.

Uses

Historically, Sphagnum moss has been used for various purposes, including as a dressing for wounds during World War I due to its antiseptic properties and high absorbency. In contemporary times, it is widely used in horticulture, especially in the cultivation of orchids and other plants requiring a moisture-retentive growing medium. Additionally, Sphagnum peat is harvested as a soil conditioner and as a component of potting and planting mixes.

Conservation

The conservation of Sphagnum and peatland ecosystems is critical for biodiversity, climate regulation, and water quality. Peatlands act as significant carbon sinks, storing vast amounts of carbon that would otherwise contribute to atmospheric CO2 levels. However, peat extraction, land use change, and climate change pose threats to these ecosystems. Conservation efforts focus on protecting peatlands, restoring degraded peatlands, and promoting sustainable management practices.