Sentinels Of The Sea( Luminous Bugs Make Ideal Watchdogs I...)

IT IS easy to dump waste in deep-ocean trenches-far harder to check that it hasn't seeped from its containers into the sea. Now, though, colonies of glowing bacteria offer hope. When they sense pollution in the water around them, they get dimmer.

"Our idea is that it's like a deep-sea canary," says William Jones, head of the team developing the biosensor at the University of Maryland Biotechnology Institute. "If light starts to drop, it would trigger neighbouring samplers into action."

Working with colleagues at the institute and at the US Naval Research Laboratory in Washington DC, Jones has screened 10 species of luminous bacteria from fish and marine mammals. One of the most promising is Photobacterium phosphoreum HE-1a, isolated from the deep-sea fish Paratrachichthys prosthemius. In a laboratory pressure chamber, the bacteria survived pressures of up to 31 megapascals-more than 300 times atmospheric pressure-equivalent to a depth of around 3000 metres.

The researchers found that P. phosphoreum HE-1a glowed up to 50 per cent less brightly when exposed to a variety of potential pollutants. These included heavy metals such as zinc, copper and cobalt, as well as chemical pollutants, including pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons typically found in oily wastes.

"HE-1a seemed to be the most robust and to respond to almost everything," says Jones. It would not distinguish one pollutant from the other, however. Its task would be simply to issue an "alarm call" that would trigger more sophisticated sensors stationed nearby.

Author: Andy Coghlan

New Scientist Issue 6th June 1998, page 21

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Contact: Claire Bowles
claire.bowles@rbi.co.uk
44 171 331 2751
New Scientist
3-Jun-1998