Friday, June 8, 2012

Japanese invasion at Oregon beach

Last week, visitors to an Oregon beach one mile north of Newport reported that they had seen a loose dock floating offshore. Not content with staying in the ocean, the object then washed ashore whereupon it was immediately scrutinized by the State authorities.

At that time, the origin of the object on Agate Beach was unknown, and there was no obvious evidence that it might have crossed the ocean. How could it have? After all, at seven feet tall, nineteen feet wide and sixty six feet long, the dock is very large and heavy.

Then, two days later came the rather amazing news that a metal placard bearing Japanese writing was found attached to the derelict dock. The placard was forwarded to the Japanese consulate in Portland, Oregon who confirmed that the dock washed ashore was debris from the March 2011 tsunami in Japan.

Shortly after the dock made landfall, staff from the Oregon Parks and Recreation Department checked it for traces of radioactivity. Fortunately, there wasn't any. But what scientists at the Hatfield Marine Science Center in Newport did find, however, was evidence of marine life.

Now while some of that marine life was native to US coastal waters, some of it was specific to the waters of Japan. Among the exotic species were different kinds of mussels, barnacles and marine algae. One invasive marine algae in particular -- Undaria pinnatifida, commonly called wakame -- was present on the structure.

As a precaution, the Oregon Department of Fish and Wildlife co-ordinated a group of volunteers to remove the organisms from the dock while also removing the salt water-dependent organisms from the beach.

 Now, as any ecologist worth his salt will tell you, invasive species such as algae and mussels can inflict a lot of damage to a local ecosystem. But fortunately, however, there are some image processing systems out there in the market that can be suitably deployed to spot the little devils.

One such system is the FlowCAM from marine instrumentation manufacturer Fluid Imaging Technologies (Yarmouth, ME, USA) which has already been put to use to analyze many types of microscopic organisms and particles in oceans, lakes, reservoirs and streams.

But better yet, it can also be equipped with a cross-polarized illumination option which can be used to detect larval-stage invasive mussel species such as Zebra and Quagga mussels. It can do so since the skeletons of the organisms are calcareous and exhibit birefringence under cross-polarized light.

The company says that using the FlowCAM with cross-polarization eliminates the human error that may be introduced using manual microscopy methods. And because the technique detects the larval stage of the species, it is able to detect the invasive species significantly earlier than other techniques.

Thankfully then, it would appear that should anymore Japanese invasions of US beaches take place, at least we can arm ourselves with the technology to determine just how ecologically unfriendly they might be.

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