A Japanese dock washes ashore on U.S West Coast

In March 2011, a devastating 9.0 earthquake struck Japan causing massive destruction. The earthquake triggered a tsunami with six to eight feet walls of water bearing down on coastal villages. The waves washed away everything – cars, houses, furniture and even bodies. To make matters worse, the flooding caused a nuclear power plant accident, putting the nation and those around the world on an alert.

But why are we talking about something that happened over a year ago now? Here’s why. Pacific ocean currents have been bringing small debris from Japan to the shorelines of Canada and the United States -- over a distance of 5000 miles. Recently, a 165 ton dock from a Japanese port washed up on a beach in Oregon. And there's more to come!

Where is the debris?

The Japanese government estimates that the tsunami swept about 5 million tons of debris into the ocean, but that 70 percent sank off shore, leaving 1.5 million tons floating. The bulk of it will hit the North American coast in 2013-2014.

According to the NOAA, an organization tracking ocean debris, many variables affect where the debris will go and when. Winds and ocean currents change constantly, making it very difficult to predict an exact date and location. Some items may sink, disperse or break up along the way. The map shows how far the debris has spread through the ocean currents.

Alien creatures

All this debris is harmful whether it is sunken or still floating on the ocean. A big part of this debris will join the already-swirling plastic garbage in the Pacific Ocean known as Great Pacific Garbage Patch (read here). The disintegrated pieces of plastic may be eaten by small fishes and travel up the food chain, or marine animals may get entangled in them. 

However, the biggest danger is that of invasive species -- non-native animals and plants that could take root in a foreign soil and destroy native plants and animals (read here). On the shipping dock, scientists found hundreds of millions of individual organisms, including a tiny species of crab, a species of algae, and a little starfish all native to Japan. Within two days, workers were out on the dock, scraping as many of the animals away as possible and burying them eight feet under the sand on the beach. They then attacked the dock with blowtorches to try to kill what was left.

The huge amount of debris can cause hazardous conditions for ships plying the Pacific route. Finally, both US and Canada worry that the sight of debris washing up on their shores may impact their tourism industry. This incident is just one more reminder of how interconnected our world has become and how incidents in one part of the world can affect places thousands of miles away.