- Compact disc users beware: Your prized music or data
could be under attack. Scientists have discovered a fungus which, under
the right conditions, will literally eat compact discs and render the
information on them completely useless.
- Victor Cardenes, a geologist at a leading Spanish research
institute, made the discovery on a trip to the Central American country
of Belize, where some friends showed him a CD which had a strange discolouration
that left it almost transparent, and unplayable.
- Intrigued, he took it back to Madrid, where he put the
sample under an electron microscope at the Superior Council for Scientific
Research. There, he found that a fungus had burrowed into the disc from
its outer edge, and eaten up the thin aluminium reflecting layer and the
polycarbonate resin that comprises the CD.
- Information is stored on CDs by a pattern of "pits"
in the aluminium layer, which is held in the resin matrix. That is then
covered in a transparent lacquer. To read the disc, laser light is shone
on to the aluminium; the presence or absence of a pit is then read as
a digital 0 or 1. If the pits cannot be located, the CD is unreadable
- "If you look at the CD from the shiny side, in the
places where the fungus has been you can see through to the other side,"
Dr Cardenes said.
- Biologists at the council concluded that the fungus belonged
to a common genus called Geotrichum, but admitted they had never before
seen this particular species.
- The cooler and drier weather in Madrid caused the fungus
to stop growing - suggesting that it thrives on tropical heat and humidity.
- Hans Hofstraat, chief organic chemist at the electronics
giant Philips - which invented the CD in 1973 - said the case was "probably
a freak incident caused by extreme weather conditions" and insisted
the fungus posed no threat to the billions of discs used around the world.