British researchers have found that magnetic fields reduce the amount of seaweed fouling underwater surfaces. This could help develop an environment friendly antifouling system which is a big problem for ships and underwater structures such as oil platforms. Weeds and barnacles growing on hulls create drag and slow down the ships and can make recycling old platforms more costly. Current antifouling methods involve painting surfaces with toxic paint such as tributyltin that poison other marine life. Researchers know that electric fields affect seaweed germination by interfering with tiny electrical currents inside cells. But this is not a practical solution. They have found magnetic fields to have a similar effect. In an experiment, bar magnets sandwiched between steel slides, placed in seawater along with some spiralled wrack seaweed embryos resulted in fewer embryos settling on the steel slides (New Scientist , Vol 168, No 2273).