More resembling a green carpet than a forest or pasture, the humble moss has a surprising amount of vigor for such a small plant. In a stunning new study, researchers have only just discovered how important this diverse group of tiny plant compounds is to ecosystems around the world.
“We were amazed to find that mosses do all these amazing things,” says David Eldridge, an ecologist at the University of New South Wales, Australia.
Eldridge and colleagues have sampled moss from over a hundred sites in eight different ecosystems and estimated that the plant’s populations cover a staggering 9.4 million square kilometers in the environments studied. That is comparable to the size of China or Canada.
The ancestors of all plants alive today, these ancient organisms are simpler in structure than their more modern descendants, with branches covered with tiny leaves that are usually only one cell thick. But that doesn’t make them any less powerful.
“Mosses don’t have the conduits that a common plant has, called xylem and phloem, for water to move through,” says Eldridge.
“But moss survives by absorbing water from the atmosphere. And some mosses, like those in the arid parts of Australia, ripple when they get dry, but they don’t die — they live forever in floating animation. We took mosses after 100 years out of a pack, splashed them with water and watched them come to life. Their cells don’t break down like ordinary plants.”
The researchers compared soils with and without moss in each of their studied areas and found greater movement of nutrients in mossy soils, increasing the cycling of everything from nitrogen and phosphorus to organic matter. Moss also acts as a reservoir for nutrients, including carbon, and currently keeps about 6.43 billion tons of this vital but currently problematic element out of our oversaturated atmosphere.
“You have all global emissions from land-use change such as grazing, clearing of vegetation, and activities related to agriculture,” explains Eldridge.
“We think mosses absorb six times more carbon dioxide, so it’s not one-for-one, it’s six times better.”
In addition, the team found that mosses keep potential pathogens in check. The research found fewer potential plant pathogens in soils inhabited by moss, and incredibly antibiotic-resistant genes were less abundant in the microbiomes of mossy habitats than in bare areas.
“We hypothesize that increasing soil carbon under mosses could reduce microbial competition and their need to produce antibiotic-resistant genes,” Eldridge and colleagues state in their article.
Moss’ shallow root networks help hold the soil together and provide a stable surface for a range of plants that give rise to more complex ecosystems. Moss also helps maintain the surface microclimate.
High densities of mat and lawn mosses such as sphagnum, hylocomium, And Ptilioncontribute the most to soil biodiversity and ecosystems, especially in areas where no trees grow, such as deserts and tundra.
And after major disturbances like volcanic eruptions, moss is one of the earliest organisms to return, after cyanobacteria and algae.
“What we show in our research is that where you have moss you have a higher level of soil health, e.g. E.g. more carbon and more nitrogen,” concludes Eldridge.
“Mosses may well be the perfect vehicle to kick start the restoration of severely degraded soils in both urban and natural areas.”
This study was published in nature geosciences.
