Monday, April 22, 2013

The Olympic Coast Clean-up 2013: Preliminary Observations increasingly common component of the intertidal ecosystem of the world's coastlines.

Initial estimates from this year's Olympic Coast Cleanup suggest that approximately 15 tons of debris were pulled off of Washington's beaches. A staggering amount, but definitely not a huge increase over previous years. One of the hypotheses out there regarding the potential of increased volumes of debris related to the Tohoku tsunami is that we would see spikes in these clean-up data...and that doesn't appear to be the case this year.

...and the other part of the modern beach, the plastic beverage bottle

This year's clean-up provided the same inspiring examples of community care and investment in the condition of Washington's outer coast. People came from all over the state (and out of the state), made a weekend of it, and dedicated hours and energy to pulling everything from chunks of styrofoam to 50 kg tires off of wilderness beaches. For the past few years I've worked the registration station at Three Rivers, serving beaches north and south of La Push. Many of the faces showing up to register have become familiar, and learning the stories of the people that come to the clean-up is one of the reasons that I love this event so much.

a local contribution to marine debris...likely from commercial fishing off of Washington's coast

Like last year I tried to get a sense of what was pulled off of those beaches in order to assess the degree to which patterns of debris are changing. Again, I was primarily interested in the "production rate" of those beaches, so like last year I turned to data collected by volunteers as they worked the beaches. We totaled 118 volunteers on "our" beaches this year (again: Rialto, First, Second and Third), and based on their estimates each volunteer averaged 19 pounds of debris, with a standard deviation of 14 pounds. Using the standard deviation as a measure of the uncertainty, I use that to estimate a total of 2280±1650 pounds collected over 6.6 miles of beach. On a per mile of beach basis (which is the metric that we attempted to use in our scenario development for the possible impact of tsunami debris), this equates to 0.17±0.12 tons/miles. We've estimated the "baseline" (i.e. before the tsunami debris) debris delivery to the beaches of Washington to be about 0.5 tons/mile. So this is another line of evidence to suggest that the Tohoku tsunami has not led to a significant and sustained spike in the amount of debris making landfall on the beach.

more fishing debris

That being said, its almost certain that some of the debris that was pulled off of the beach was, indeed, "tsunami debris". The first photo of this post shows a sub-sample of the styrofoam bits pulled off of Rialto Beach. There has been much speculation that pulses of styrofoam that made landfall in Washington starting last summer were derived at least in part from insulation material - from homes, businesses and other structures - released into the ocean by the destructive power of the tsunami. This material is particularly worrisome because it breaks apart fairly easily and some suspect has ecological impacts out of proportion with its relatively low mass. We don't know if there is more styrofoam this year than in previous years since those sorts of information aren't tracked carefully.

one of the finds of the day - a huge chunk of styrofoam that appeared to have been a part of an old dock or structure. Chunks of concrete were attached to it.

Another very cool part of this year's clean-up, and one that will hopefully provide much more detailed information on the mass and composition of debris recovered, was the work of a group of Western Washington University students at a selection of beaches (including Third Beach). As part of a project funded by the North Pacific Coast Marine Resource Committee they focused on carefully sorting and weighing debris.

students from Huxley College of Environmental Studies carefully sorted and measured much of the debris off of selected beaches as part of a project funded by the North Pacific Coast Marine Resource Committee

A view of the dumpster at the trailhead of Third Beach near the end of the day

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