The longest data series on plastic in the open sea was collected by the student-sailor-scientists of the Sea Education Association (SEA). SEA runs the Sea Semester, where undergraduate and high school students can learn oceanography, maritime history, and seamanship aboard one of two gorgeous tall ships, one in the Atlantic, one in the Pacific.* Now SEA has embarked on an extensive study of plastic debris in the North Atlantic aboard the the SSV Corwith Cramer.
Our hauls of plastic have been fairly consistent, and we’ve tallied about ~70 pieces per net tow, which works out to a surface concentration of around 50,000 pieces per square kilometer. These values are well within the range that we’ve found in this region before, but do not represent the super high values that define the center of the accumulation zone.
Assuming that each plastic piece weighs less than a 0.1 g, this means that within the area that we can see from the deck of our ship (about 4.5 nautical miles) there are almost 800 pounds of tiny plastic fragments floating in the surface waters. It is extremely important to realize that the plastic fragments are small enough that you cannot easily observe them from the deck of the ship. Thus, we do not generally know if we’re pulling up a net full of plastic or not. This makes for exciting – and troubling – first glances at the sample as we empty the contents of the net from cod-end jar (the collection vessel at the end of the net) into a bucket.
Here’s a video of Giora talking about their preparations to go to sea for 35 days:
* Full disclosure: I’m super excited to be headed across the Pacific with SEA’s other ship, the SSV Robert C. Seamans, in a few weeks. More on that soon!