The desert holds a hidden breath. Within minutes of a rare rainfall, dry soils near the Dead Sea began exhaling powerful greenhouse gases, even when stripped of microbial life.
That startling finding comes from a new study led by Dr. Isaac Yagle and Prof. Ilya Gelfand at Ben-Gurion University of the Negev, published in Scientific Reports. The work upends long-standing assumptions that post-rain bursts of carbon dioxide (CO2), nitrous oxide (N2O), and nitric oxide (NO) are solely the work of soil microbes. Instead, chemistry alone can spark these emissions.
To test the role of biology, the team collected intact soil cores from Israel’s arid landscapes and sterilized half using high-dose gamma radiation. This procedure destroyed most microbial life while preserving the soil’s structure. Both the live and sterilized soils were then wetted in the lab. Within five minutes, emissions of CO2 and nitrogen oxides surged from all samples. The surprise came in the magnitude: sterilized soils released up to 13 times more NO and five times more N2O than the living soils.
“Our results show that chemical reactions, not just biology, drive these immediate emissions, especially for nitrogen-based gases,” said Dr. Yagle.
Carbon dioxide pulses still ran higher in live soils, fueled by microbial respiration. Yet even there, nearly half of the CO2 came from abiotic sources such as carbonate reactions triggered by water. The findings underscore that the first flush of gases after rain is not just biology waking up, but chemistry set loose by sudden wetting.
This matters because drylands are expanding worldwide, covering more than 40 percent of Earth’s land surface. Rainfall patterns in these regions are becoming more erratic, with longer droughts punctuated by intense downpours. Each wetting event primes a chemical release that, multiplied across continents, could reshape regional greenhouse gas budgets. By ignoring abiotic pulses, models may have underestimated desert contributions to climate forcing.
“Our work highlights the need to factor in abiotic processes when assessing the environmental impact of dryland soils,” added Prof. Gelfand. “Ignoring them may lead to underestimation of regional and global emissions.”
Revealing The Desert’s Hidden Chemistry
For decades, ecologists observed the Birch effect, soils releasing sudden bursts of gas after rain, but explained it largely in terms of microbial activity. This study provides direct evidence that the first wave, at least, can be driven without microbes at all. Chemical pathways include the rapid breakdown of hydroxylamine and nitrite, or carbonate reactions that liberate CO2. In sterilized soils, gamma irradiation may even have freed up trapped nitrogen substrates, fueling faster abiotic conversions.
The study also resonates beyond Israel’s Negev. Other drylands, from the American Southwest to the Sahel, share similar soils and extreme wet-dry cycles. If abiotic reactions scale globally, the role of deserts in climate dynamics may be more than background noise (they may be active chemical engines responding to each rainfall).
As scientists refine carbon and nitrogen budgets, they will now need to balance not only the respiration of life but the restless chemistry of lifeless soil. The desert, it turns out, speaks in gases, whether microbes are there or not.
Explainer: What Are Pulse Emissions?
When rain falls on long-dry soil, it often triggers a sudden pulse of greenhouse gases. In living soils, microbes switch on quickly, respiring carbon dioxide and transforming nitrogen compounds into N2O and NO. But this new research shows that non-biological, or abiotic, reactions also play a major role, especially in the first minutes after wetting. For example, carbonates in soil can fizz into CO2, while nitrite compounds break down chemically into nitrogen gases. These pulses, though brief, can account for a large share of annual emissions in drylands, making them critical to understanding the global climate balance.
Journal: Scientific Reports
DOI: 10.1038/s41598-025-12362-3
ScienceBlog.com has no paywalls, no sponsored content, and no agenda beyond getting the science right. Every story here is written to inform, not to impress an advertiser or push a point of view.
Good science journalism takes time — reading the papers, checking the claims, finding researchers who can put findings in context. We do that work because we think it matters.
If you find this site useful, consider supporting it with a donation. Even a few dollars a month helps keep the coverage independent and free for everyone.