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Invading zebra mussels have colonised at least 2000 square kilometres of soft
sediment on the beds of the Great Lakes, says a report in Nature (vol
393, p 27). It was thought that the mussels could only grow on hard surfaces.
Paul Berkman of Ohio State University in Columbus says his discovery that the
creatures can grow on soft substrates has 鈥渟tunned鈥� US and Canadian officials
combating the invaders. 鈥淭he potential expansion is huge,鈥� he says.