For several decades, between 1800 and 1900, one of the popular therapies more or less for any illness envisaged exposure to sea air, without any supporting scientific prerequisite. Now, however, a study published in the scientific journal Nature Communications by a multidisciplinary team of Californian researchers (including those from the Scripps Institution of Oceanography, the Craig Venter Institute and the University of San Diego) raises more than one doubt about virtue of that belief, except for sea iodine inhalation, which is certainly good for some people. US biologists and doctors have in fact discovered that the sea aerosol contains many bacterial and viral species, some of which are potentially pathogenic to humans.

To achieve these results, researchers, who have been working on the project since 2010, have used very sophisticated equipment at the Hydraulics Lab of the Scripps Institution. This “machine” conveys the ocean water into a channel, where are reproduced physical conditions giving rise to waves. Tests lasted for 34 days and led to identify many different bacteria and viruses kind “thrown” in the air by the wave motion. In particular, researchers found families of Corynebacteria and Actinobacteria, not harmful to humans, but also dangerous bacteria, such as Legionella or Escherichia coli (perhaps coming from pollutant discharges and rethrown, in turn, in the air). As for viruses, some kind of herpes virus has been identified, including infectious agents of diseases such as chickenpox and herpes zoster, although their potential danger in this form is yet to be proven.

According to researchers, the microorganism’s membranes carrying fat and wax molecules or, in any case, in the coatings are transported and expelled from the sea waves. These substances cause them, so to speak, to be “waterproof” and therefore easier to be thrown out of water.

In the coming months, scholars will try to understand to what extent bacteria and potentially infectious viruses can travel in sea waters, and following which pathways. In the past few years, a group of Californian researchers, led by Kim Prather, had already succeeded in demonstrating that many types of microorganisms are able to travel tens of thousands of kilometers, through wind, sometimes entering the ocean and re-emerging from water along the journey. But this long travel can change their chemical characteristics and the ability to infect humans (and also their effects on cloud formation …). Many of the chemical components found in marine aerosols, researchers add, derive instead from microorganisms permanently living in oceans.