Field of Science

Bryophyte week - why Sphagnum matters

If your knowledge of Sphagnum moss starts and ends with the bale of soil additive in your garden shed, then this may come as a surprise. Sphagnum is a significant component of plant communities at high latitudes. It's a pretty nifty moss because it can hold 20-30 times its own weight in water because it's "leaves" (leafy organs called enations) are a reticulate network of chlorophyll bearing cells (stained green) surrounding large dead cells that take up water by capillary action. In a manner of speaking they are an aquatic organism that takes its water with it. Sphagnum bogs accumulate significant amounts biomass which means they are carbon reservoirs. Decomposition is very slow because of the low pH (acidic) and the cold climate. Eventually Sphagnum compacts into peat, which sometimes gets dug, dried, and burned to cure barley malt used to make Scotch whiskey. But as temperatures go up and winters get shorter, all that stored carbon gets released at a faster rate as shown by a number of studies way up north there in Scandinavian countries. Global warming vs. whiskey; OK, that's a non-starter as an issue. But this shows how cumulative small changes can result in a tipping point were all of a sudden carbon dioxide in the atmosphere rises really fast, and everyone finally goes, gee, that's not good, but now it's too late.

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