Saharan dust carries bacteria across the Atlantic to Brazil’s Amazon rainforest, according to a 2026 study analyzing air samples collected in 2020. The research, led by University of Graz biologist Bettina Weber, found the dust alters airborne microbial communities while tripling endotoxin levels, raising health concerns.
Transatlantic Journey from African Biocrusts to the Amazon
Microbes from Africa’s arid regions travel 10 days across the Atlantic to the Amazon, carried by Saharan dust clouds. Researchers collected air samples at the ATTO tower in Brazil, using filters at 42 and 323 meters to capture microbial material. Genetic analysis revealed bacteria matching those in Sahara soil crusts, confirming transatlantic transport.
Soils in arid regions and deserts are largely colonized by microbial communities… transported from African biocrusts across the Atlantic by wind to Brazil’s rainforest,
explained Weber.
Endotoxin Surges and the Impact on Air Quality
The study found Saharan dust introduced bacteria typical of dry soils into the Amazon’s air, while fungal spore communities remained stable. Researchers observed a threefold increase in endotoxins—substances linked to inflammation in humans—during dust events.
Mineral Tracers and Resilient Fungal Communities
The team used a sensitive enzyme test called LAL to measure endotoxins, while computational models traced dust origins to the Sahara. Mineral composition of samples, including high calcite levels, further confirmed the African source.
Unresolved Viability and Future Health Studies
Scientists plan to investigate whether the transported microbes remain viable after their transatlantic journey and their potential health impacts. The current study did not determine if the collected genetic material was still alive.
The findings highlight the complex interplay between climate, microbiology, and human health. While the Amazon’s fungal spores appear resilient to Saharan dust, the surge in endotoxins raises questions about long-term respiratory effects. The study, published in Communications Earth & Environment, underscores the need for further research into global microbial transport networks.