A new study has found that bacteria can travel from one continent to another via atmospheric dust. According to the study, the microbes may not only affect human or animals' health but can also impact the climate and ecosystem. The research, published in the journal Atmospheric Research, has unfolded the mystery of the transport of microorganisms across continents via 'giant' atmospheric particles called iberulites that could be inhaled by humans.
Scientists said that iberulites are giant atmospheric bioaerosols made of multiple minerals, measuring on average one hundred microns approximately. While these bioaerosols were discovered in 2008, the scientists said the mechanism by which bacteria are involved in the formation of atmospheric iberulites remained unknown.
In the current study, the researchers analysed atmospheric dust deposits in the city of Granada in Spain. They found that the composition of these deposits was heterogeneous, comprising predominantly clay, quartz, and carbonate minerals. They said the aerosols also contained brochosomes which are microscopic granules secreted by insects such as grasshoppers.
According to the study, the dust originated from the Sahara Desert in north-northeast Africa and local soils with evidence of atmospheric interactions between these components and clouds. Analysing the iberulites, the researchers found that they formed as a result of chemical and physical interactions between dust grains, the microorganisms from Saharan soils that initiate the aerosol formation, and water-vapour molecules from clouds. "The droplet of water agglutinates dust particles of different sizes in its interior together with bacteria in suspension', according to the study.
The iberulites aid microorganisms to travel great inter-continental distances on atmospheric currents such as the Saharan Air Layer (SAL). They believe these aerosols may exist throughout the world, primarily in those regions where dust is carried in from desert regions.
"Bacteria can survive in iberulites because these provide a nutritious medium, a microhabitat rich in nutrients, and they protect the bacteria from ultraviolet radiation," said Alberto Molinero Garcia, a co-author of the study.(With PTI inputs)