A team of US and German researchers has measured the highest level of ultraviolet radiation ever recorded on Earth's surface - in the Bolivian Andes - and their study indicates that depleting ozone may be what caused such harmful radiation levels.

 

Only 1,500 miles from the equator, the Bolivian Andes boasted levels far above those normally considered to be harmful to both terrestrial and aquatic life. Using the European Light Dosimeter Network (Eldonet), researchers came to the surprising realization that South America, of all places, demonstrated record ultraviolet (UV) fluxes in the summer of 2003 and 2004.

 

The measurements were taken as the team of researchers was investigating high altitude Andean lakes as part of an astrobiology study of Mars-like environments. The combination of midday sun and high elevation of these Bolivian mountains - some 20,000 feet above sea level - produced higher irradiance levels because of naturally low ozone in such locations.

 

Researchers speculate that this increased UV flux may have been caused by ozone depletion - a result of increased aerosols from both seasonal storms and fires in the area. Also, a large solar flare occurred just two weeks before the highest UV fluxes were registered. While the evidence linking the solar event to the record-breaking radiation is only circumstantial, particles from such flares are known to affect atmospheric chemistry and may have increased ozone depletion.

 

The researchers, who published their study in the journal Frontiers in Environmental Science, believe that ozone levels should be more closely monitored, as this sort of event could happen again, "because the factors that caused it are not rare".