Two years ago, 24 million tons of dust rose high above Africa, forming a cloud that hovered across the Atlantic, hiding Puerto Rico in a pink patina. An unusually meandering jet stream contributed to the formation of the monstrous dust cloud. But environmentalists have now identified another factor contributing to such storms: the disappearance of the “biocrust,” a microbial mat that covers dry soil and keeps dust in place.
Biodust is a hard surface coating, or “skin,” typically a few millimeters thick, containing a thriving community of fungi, lichens, algae, cyanobacteria, and other microbes. Bettina Weber, an ecologist at the University of Graz and co-author of the book NatureGeoscience Published study. But this gum is likely to weaken in the future, having been trampled on and destroyed by livestock as a result of climate change, leaving the soil prey to the winds. USGS ecologist Rebecca Finger-Higgins said the dust study shows “that the loss of bio-dust in a particular region of the world can have far-reaching effects.”
So far, ecologists have paid little attention to the biome that covers soils in arid, semi-arid, and extremely cold regions around the world. However, researchers have realized that these layers produce and process nutrients that other organisms in the area need to thrive, especially in arid environments. It also helps dry soil retain low moisture levels.
In 2018, Weber and her colleagues mapped all types of bio-dust on Earth and concluded that they cover 12 percent of the Earth’s surface. They then collaborated with climate modelers and dust experts to find out how much dust the bioglue currently prevents from forming. First, the researchers identified the winds needed to destroy biological soils and blow up the soil. They then calculated dust emissions at 31 different sites and fed the results into a model of global dust levels – and how much they would have increased without bio-dust.
According to Weber and her team, biosynthetic insects reduce dust pollution in the air by 700 million tons annually. That amount would bury the entirety of New York under 14 inches of dust. The study notes that “biological forests play a key role in preventing dust emissions worldwide,” says Fernando Maestre, a dryland ecologist at the University of Alicante.
Dust can aggravate respiratory problems and other illnesses
Dust storms like the one that devastated cities in southeastern Brazil in 2021 could become more frequent as soils in arid regions retain less moisture. Between 25 and 40 percent of these crusts will disappear in the next 65 years, says Emilio Rodriguez Caballero, who was involved in the study and now works at the University of Almeria. On the other hand, climate change threatens soil biota, and can cause about half of the destruction. People and livestock also tread on the husks or under the wheels of agricultural machinery.
Finger-Higgens and colleagues document the effects of climate in more detail. In a long-term study of areas in Utah’s Canyonlands National Park, they found that biogeococcus lichens in particular suffer from warming. With temperatures in the Canyonlands rising 0.27 degrees Celsius per decade, lichens, especially those that help convert nitrogen in the air into a form other organisms can use, have all but disappeared, the team reported in April in the journal. PNAS.
Fewer plants can survive with less nitrogen, resulting in bare soil and more dust emissions, according to Finger-Higgens. According to the researchers, some of the effects of the dustiest climate are still unclear. The effect of dust on temperatures depends in part on the size of the particles. Dust particles act as nuclei for cloud formation and can cause snow to melt faster. While dust helps transport nutrients essential to plant life, it can exacerbate respiratory problems and other health conditions in humans.
Previously, it was assumed that dusty areas such as the coast would become greener and less dusty because higher levels of carbon dioxide have a fertilizing effect. Weber and colleagues note that the loss of biodust is likely to nullify this process to some extent.
Climate makers have often neglected how dust affects temperature and precipitation, says Michael Mann, an atmospheric researcher at Penn State University. However, the effects of fading biological disappearances shouldn’t be so dramatic that they make a big difference to global climate models, he says.
However, Joseph Prospero, an atmospheric chemist at the University of Miami, warns that there are vast regions on Earth where information about bio-dust is scarce. Weber, Maestre, Finger-Higgens, and other experts are now trying to fund biometric blister measurements worldwide.
According to the researchers, the need to protect these vulnerable communities is already clear. Maestri says reducing emissions and changing agricultural and other land-use practices can help halt its degradation. “The findings make a strong case for biocrust protection worldwide.”
This post is Originally in Science Sciences Published and published by AAAS. German Liberation: cvei