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Latest Expedition Journal

October 23:  Day 21

Posted by Emelia DeForce

Marine Debris

One of the key research components of this trip is a survey for tsunami debris.  Recent news has reported objects from the 2011 Japanese tsunami washing up on U.S. shorelines, such as an overturned fishing boat near Oahu, Hawaii.  Numerical models by Nikolai Maximenko  (University of Hawaii at Manoa) show that our sailing expedition track is close to the estimated path of this tsunami debris traveling east towards North America and turning south towards Hawaii.  We have adopted three daytime protocols for monitoring this and any other large, visible floating debris.

For what we call “opportunisitic” sightings, a clipboard sits near the helm with yellow-lined paper and instructions:  “If you see anything float by, log its GPS location, time of sighting, and approximate size/color.”  This survey alone has generated 282 sightings ranging from plastic shipping wrap to a rare glass buoy that we sighted today.  The next and more scientific protocol is carried out at the top of each hour for 10 minutes by a science watch stander at the bow.  Anything seen within one boat length of the ship is recorded with similar information, then immediately transferred to the computer in the lab.  This has produced 248 sightings.  Finally, Zora McGinnis, a master's student at Hawaii Pacific University, is on this expedition to gather data—including marine debris observations—for her thesis.  For 53 hours (and counting) she has fastidiously observed 1030 pieces ranging from small bits of Styrofoam to a Cookie Monster inner tube.  

We haven’t seen soil in what seems like months.  In the 1,200 miles we have sailed since leaving San Diego, this means we have seen about 10 pieces per hour in the gyre during the day.  This only includes objects visible to the naked eye—those pieces we can’t see are numerically far greater.  

It is difficult to say if most or any of this gyre debris can be attributed to the tsunami.  We can say that these pieces have growth of marine organisms and some include small rafting ecosystems with fish feeding on them.  All of the objects we have caught (by boat hook or dip net) for scientific analysis have what appear to be Japanese print characters.  Still, it is difficult to confirm that this debris was carried out to sea by the Japanese tsunami.  

The survey data that we are gathering on this expedition will be used to help fill in gaps of information for better marine debris modeling.  Sea Education Association has just started to report this type of information to NOAA (National Oceanic and Atmospheric Administration).  

Finally, Dr. Deb Goodwin, chief scientist on a recent SEA Semester expedition from Hawaii to California, believes that while at sea this summer she and her students spotted the same boat that recently turned up in Hawaii.  This is why we carry out this open-ocean survey work—because no matter how far away we live, we are ultimately connected by the ocean.