Biocrusts biocrust helps reduce global dust emissions by 60%

In the relentless battle against dust, man possesses an extensive arsenal of weapons, from microfiber cloths to vacuum cleaners. But new research shows that no technology can compare to nature's secret weapon - biological crust.

These Biocrusts are thin, cohesive layers of soil, held together by dirt-dwelling organisms, often creating arid landscapes. Although innocuous, researchers now estimate that these rough layers of skin block about 700 teragrams, according to ecologist Bettina Weber and colleagues reporting online May 16 in the journal Nature Geoscience. 30,000 times the mass of the Statue of Liberty) into the air each year, reducing global payloads to a staggering 60%.

Lichens (pinkish-white) and cyanobacteria (dark brown to blackish) form a biofilm that carpets the ground among succulents and shrubs in the Succulent Karoo ecoregion in South Africa.

Weber, of the Max Planck Institute of Chemistry in Mainz, Germany, also adds that dryland ecosystems, such as savannas, shrubs and deserts, may seem barren, but they are providing an important natural service. importance is often overlooked. The findings "really call for conservation of biological reliability".

Biocrust covers about 12% of the planet's land surface and is most commonly found in arid regions. They are built up by communities of fungi, lichens, cyanobacteria, and other microorganisms that live in the top millimeter of soil and create binders that bind soil particles together. In arid soil ecosystems, biocrust plays an important role in concentrating nutrients such as carbon and nitrogen and also helps prevent soil erosion.

Different types of Biocrusts.

And since most of the world's dust comes from dry lands, biofilms are important for keeping dust from clinging to the ground. Falling dust can carry nutrients beneficial to plants, but it can also reduce water and air quality, cause glaciers to melt faster, and reduce river flows. In the Upper Colorado River Basin, for example, researchers found that dust not only reduces snow's ability to reflect sunlight, but also shortens the amount of time it takes for snow to fall by weeks, reducing meltwater by 5%. flows into the Colorado River. This is more water than the city of Las Vegas collects in a year, says Matthew Bowker, an ecologist from Northern Arizona University in Flagstaff who was not involved in the new study.

Experiments have demonstrated that biological crust strengthens soils against erosion, but Weber and her colleagues are curious how that impact plays out on a global scale. So they took data from experimental studies that measured the wind velocity needed to erode dust from different soils and calculated how differences in biocoverage affect the generation of dust. out dust. They found that the wind velocity required to erode dust from soil completely shielded by the biofilm was on average 4.8 times greater than the wind velocity required to erode bare soil.

The researchers then combined their results, along with global biocoverage data, into a global climate simulation, allowing them to estimate how much dust the world's biofilms contain. trapped world every year.

Bowker said: 'Nobody has really tried to do that calculation globally before. "Even if their numbers are off, it shows us that the real number is probably substantial."

Using projections of future climate conditions and data on conditions that biocrust can tolerate, Weber and her colleagues estimate that by 2070, climate variability and change Land use can lead to biocrust losses of 25 to 40 percent, which would increase global dust emissions by 5 to 15 percent.

Biofilm conservation and restoration will be key to reducing future soil erosion and dust production. It is hoped that these results will help spur more discussions about the impact of land use changes on biological health, he said. "We need to have those conversations," Bowker added.