April 13, 2012

Reef Check Spotlight: Japanese Tsunami Debris


By Reef Check California Director Dr. Jan Freiwald

In a recent announcement, the governors of the US West Coast states and the Premier of British Columbia published a joint response to the potential of marine debris washing up along the West Coast as a result of the earthquake and tsunami in Japan last March. The states will work together to develop a communication strategy, respond to any environmental threats that might arise and insure the safety of workers and citizens. An estimated 1.5 million tons of debris is still floating in the Pacific Ocean as a result of the tsunami. It is very unlikely that any of this is radioactively contaminated because of the sequence of events after the tsunami and the Fukushima reactor melt down. Most of the debris was already washed out to sea before the radiation leak.

The West Coast and Japan are mainly connected through two large oceanographic currents, the California Current and the Kuroshio Current. The Kuroshio Current flows north-eastward along the Japanese coast and into the northern Pacific, whereas the California current flows southward along the west coast of the United States. Both of these currents connect in the northern Pacific in a region known as the North Pacific Gyre. While the likelihood of finding things that were washed into the ocean as a result of the earthquake and tsunami are rather low along the west coast, the fact that it is a real concern demonstrates how connected the world is through these major ocean currents. Scientists from the National Oceanic and Atmospheric Administration have estimated that it would take buoyant debris about a year to reach the West Coast based on the current speeds and wind patterns over the last year.

One particularly large piece of ‘debris’ was sunk by the U.S. Coast Guard in early April. A Japanese fishing vessel destined for the scrap yard was washed out to sea by the tsunami and had been drifting through the northern Pacific as a ‘ghost ship’ ever since. The Coast Guard decided that it was safer to sink the vessel before it reached shallow waters or busy shipping lanes off Alaska than trying to salvage it.

This connectedness is not something that we think of very often when considering environmental impacts of local actions. In most cases we are concerned with much smaller spatial scales but this tragic event demonstrates how events in one part of the world can affect large regions; it demonstrates how interconnected the continents are. Other major currents connect the continents in the Atlantic and in the Indian Ocean as well.

To find out more about the potential of debris arriving along the West Coast and for instructions on what to do if debris is found, go to: http://disasterdebris.wordpress.com/ or http://marinedebris.noaa.gov/info/japanfaqs.html