Japan tsunami may have damaged marine life

Ali Best, ninemsn 18 Mar 11;

The devastating tsunami that swept through north east Japan last Friday may have significantly unsettled the wider marine environment, an expert has said.

The huge wave that followed the 9-magnitude quake carried huge volumes of water in land, destroying towns and engulfing everything in its path.

It returns back to sea with a great amount of force and can be directed by the shape of the coastal floor, causing whirlpools similar to the huge swirl that was seen last week.

The damage caused by such a formation is dependent on the area where it occurs, but it can lead to significant long-term harm to marine life.

"It's a little bit like a cyclone on a smaller scale," said Dr Mark Gibbs, Deputy Chief of the CSIRO Marine and Atmospheric Research group. "And the tsunami itself going through there would have caused a lot of damage.

"Those sorts of massive events will suck up lots of seaweeds and animals and cause a lot of (marine) mortality."

The wave would have dragged a lot of sediment and debris from the land and deposited it into the ocean. Experts believe this impact will affect light and sediment levels, further damaging the unique marine environment.

Mark Baird, a biological oceanographer at Sydney's University of Technology, said it could take years for the area to regenerate, even if there was only grass on the sea floor.

"If it was just micro-organisms in a muddy bed it might take only a short time," he said.

"But if there's sea grass it may take a few years it to grow back."