Australian prepares for tsunami debris mission across Pacific

Millions of tonnes of debris were swept into the ocean following the tsunami and earthquake in Japan. [Reuters]
PHOTO

Millions of tonnes of debris were swept into the ocean following the tsunami and earthquake in Japan. [Reuters]

Ali Benton

Last Updated: Tue, 15 May 2012 11:13:00 +1000

Australian environmentalist Paul Sharp is about to set off on the fishing trip of a lifetime, but Mr Sharp will not be catching fish - he will be taking part in the first scientific survey of Japanese tsunami debris.

After the 2011 tsunami, an estimated 5 million tonnes of debris was washed into the water.

About 70 per cent of that debris sank near the shore, but 1.7 million tonnes remains in the ocean, slowly making its way across the Pacific towards the United States.

Scientists want to know how the swirling vortex of currents contaminated with pollution is affecting the marine ecology.

The debris found in the Pacific Ocean so far ranges from small pieces of plastic to a Harley-Davidson motorbike which washed ashore on an island off the coast of Canada.

Along with other world leaders in marine plastic pollution, Mr Sharp will be on the scientific vessel Sea Dragon for a whole month to study the amount of plastic debris left in the ocean post-tsunami.

"We will be keeping a visual watch, looking for larger pieces of debris that we can visually identify," he told Radio National Breakfast.

"If we can we will bring them on board so we can examine them, otherwise we will document them as we go past.

"On a smaller scale we are also deploying what is known as a manta trawl, which we deploy every 60 kilometres on the journey, and that allows us to sample for microplastics in the surface waters."

The expedition is the first scientific fact-finding mission on just how much plastic entered the water after the tsunami

"There's been a relatively recent shift in perception where we've gone from looking at plastic as a litter problem to looking at plastic as a pollution problem when it's in the environment," Mr Sharp said.

"So we're really trying to gather data that will support that, to help us speed change in the way we use plastics, so we can stop it getting out there in the first place."

One of the key goals of the expedition is to measure the level of toxins in the floating plastics.

"We will be able to learn what kind of densities of toxins are attaching themselves to the plastic surface, which is really interesting because this plastic can then act as a vector to introduce toxins into the food web," Mr Sharp said.

"That's not a good thing because the kind of toxins that can be introduced into the food web bioaccumulate, so they end up in the seafood that we eat.

"We are also going to look at colonisation of the plastic by exotic species, because plastic can also transfer species from one part of the ocean to another part of the ocean, where they wouldn't normally be found.

"Literally they attach themselves and live to it, or if it's a larger piece of debris the animals can seek shelter under it so they drift along with the plastic as it moves through the ocean."

Dodging debris


One of the key hazards for the expedition will be dodging the debris that is floating in the ocean.

Earlier this year a Japanese 'ghost trawler' was found floating in the northern Pacific, and a Japanese soccer ball recently washed up in Alaska.

The National Oceanic and Atmospheric Administration's Marine Debris Program in the United States has a close eye on the problem.

"We are working with the shipping and fishing fleets to let them know about tsunami debris, but also actually to work with them for them to let us know about tsunami debris," regional coordinator Peter Murphy said.

"This tsunami debris could be really anything - it could be buoys, household items, fishing nets - and with those items spread out you have them dispersed widely over a large area."

So far ships have managed to avoid debris.

"There have not been reported impacts of shipping vessels and tsunami debris at this point," Mr Murphy said.

"There have been sightings of debris that could be from the tsunami, but there haven't been impacts or collisions."

The tsunami debris field expedition leaves Tokyo on May 30.

Mr Sharp will set sail across the top of the Pacific Ocean and head down to Hawaii.

"There's going to be navigation hazards out there - there could be anything from the size of fridges to whole ships that are bigger than us, so a collision could quite easily sink us within minutes," he said.

"My father's yacht was actually lost at sea after hitting a shipping container so there's a little bit of close history there."

Mr Sharp's father's ship may have been lost at sea, but there was no family disaster.

"He survived," he said.

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