A network of researchers in northeastern Brazil is working to protect the biome

Art by Valentina Fraiz

Pedro Lira

The Tupi-Guarani people called the pale landscape of trees and shrubs with light-colored trunks ka’a tinga, meaning “white forest.” The Caatinga is unique to Brazil and covers the semi-arid region of the Northeast, home to around 28 million people. It is a highly fragile biome that has experienced irreversible environmental degradation.

The Caatinga is highly susceptible to climate change due to its arid conditions and slow vegetation recovery. It faces a particularly difficult threat: desertification. This is an advanced stage of environmental degradation in which land once covered by native plants becomes dry and barren, unable to support most forms of life. This transformation is driven by natural factors, such as high temperatures and scarce rainfall, and intensified by human activities, including deforestation, fire, and unsustainable land use. 

A solution may be closer than it seems, though. During a field trip to Irauçuba, Ceará, to study how microorganisms respond to desertification, agronomist Arthur Prudêncio, a professor at the Federal University of Ceará, was surprised to notice biological crusts forming on the soil surface. These crusts are thin layers formed by bacteria that bind soil particles, helping to protect the ground from erosion. 

“These bacteria release organic compounds, especially carbohydrates produced through photosynthesis,” the professor explains. “In an effort to survive, they form biofilms—biological crusts—that make the soil more fertile and protected.”

Areas lacking vegetation, such as desertified lands, are vulnerable to wind and rain, which strip away soil and hinder natural regrowth. Biological crusts can play a key role in reversing this process. As these bacterial communities settle in, they increase the levels of carbon, nitrogen, and other beneficial elements. This helps stabilize the soil and enables new life forms, such as fungi and small plants, to take hold. “That’s when the process of covering the land starts over,” says Prudêncio. 

He and his research group are betting that they can isolate these bacteria and artificially trigger crust formation to accelerate the restoration of degraded land in the semi-arid region. The research now centers on isolating and identifying the bacterial strains that are most efficient at producing these compounds.

The first article on the subject sparked interest among scientists throughout Brazil’s Northeast region. Researchers from other states asked themselves how biological crusts formed in their own regions. Prudêncio set up a data collection and analysis network that gradually evolved into research hubs across the region. This gave rise to the Caatinga Microbiome Initiative: a network of over 20 Brazilian and international researchers and professors dedicated to studying the biome and its relationship with soil health through a holistic research approach.

“I am passionate about the Caatinga,” says Prudêncio, who was born in Pernambuco. “I am from the Northeast and committed to preserving this biome. I know there is still enormous, untapped potential here.” Given how little the Caatinga has been studied, researchers are likely to discover new bacteria and novel biotechnological processes.