快猫短视频

SHIPS and oil platforms could use magnets to ward off squatters. British
researchers have found that magnetic fields reduce the amount of seaweed fouling
underwater surfaces. They hope that the technique could be used as an
environmentally friendly antifouling system.

Fouling is a major problem for ships and underwater structures such as
platforms. Weeds and barnacles growing on hulls create drag and slow shipping
down, and can make recycling old platforms more costly. Current antifouling
methods involve painting surfaces with toxic paint such as tributyltin. But
these can poison other sea creatures such as shellfish
(快猫短视频, 8 May 1999, p 23).

Researchers have long known that electric fields affect seaweed germination
by interfering with tiny electrical currents inside cells. But electric fields
aren鈥檛 always practical for use on the water. So Jill Shaw and her colleagues at
the Glasgow Marine Technology Centre and Dove Marine Laboratory, University of
Newcastle upon Tyne wondered whether a magnetic field might have the same
effect.

To find out, Shaw sandwiched bar magnets between two glass or steel slides,
and placed them in seawater along with some spiralled wrack seaweed embryos. She
found that far fewer embryos settled on the steel slides when the magnet was
present. More embryos settled on the glass slides, but they tended to congregate
at the magnetic poles, she told a meeting of the British Ecological Society last
week.

Although the system doesn鈥檛 prevent fouling completely, Shaw believes that it
could be worth incorporating magnets in steel structures. 鈥淚 don鈥檛 think there鈥檚
anything鈥攗nless it鈥檚 as toxic as TBT鈥攖hat will be 100 per cent
effective,鈥� she says. 鈥淚t sounds a good idea, but there鈥檚 work to be done,鈥� says
William Perry, a naval architect at the Southampton Institute.