Science Results : Daily Update

Daily Update | Current SEA Research

June 21, 2010

By Giora Proskurowski

This morning, after our dawn neuston station (0430) we made our turn south. The primary objective of this expedition was to extensively map the region of high plastic concentrations in the North Atlantic as far east as possible, with the hope of finding decreasing concentrations at the eastern edge.

Given our limited resources of food for 33 people for 35 days, and fuel to run our generators and motor during light or unfavorable wind conditions, we figured the best case scenario would be to get as far east as 40°W. This longitude is just to the east of the Mid-Atlantic Ridge, the seafloor spreading center that divides the North American and Eurasian plates, and is far enough from Bermuda (over 1200 nautical miles) that getting back to Bermuda while executing a saw-tooth mapping track will be a challenge.

We are currently approaching 40°W, and I can safely say that we have not found the eastern boundary of high concentrations of plastics in the North Atlantic. In fact, at 0930 this morning we sampled what I predict will be the largest amount of plastic SEA has ever recorded in 25 years of sampling. This multi-decadal dataset includes some 400 tows in the North Pacifc subtropical gyre (the misleadingly nicknamed "Great Pacific Garbage Patch") and more than 6200 tows here in the North Atlantic. The amount of plastic we collected this morning is staggering.

In an attempt to get some statistics on the variability of data we collect in our tows we have been simultaneously towing two neuston nets, "wing-on-wing", like a schooner running with the wind or a fishing boat spooling gear off of both sides. When the tow started I could distinctly see a few pieces in the upper layer of water, and it looked like it was going to be a "good one", one where we got some plastic to keep the lab busy.

A couple of minutes into the tow suddenly we started to see more and more macro debris, sometimes appearing to form loosely organized windrows (indicative of a special type of turbulence in the upper ocean called Langmuir circulation). While everyone was making comments about all the debris, a red 5-gallon bucket drifted by the port bow, with a school of about 20 fish underneath it. That was pretty neat, the bucket was sustaining its own little community.

All of a sudden the bucket bobbed toward our neuston net and was trapped inside! Fearing the bucket would tear our net, we ended that tow early, and pulled the bucket, two of its associated school of grey triggerfish, and thousands of tiny fragments of plastic up on deck. Skye Moret quickly dissected one of the fish and found 47 pieces of plastic in its guts. This school of fish, a coastal fish typically living on reefs, was thousands of miles from land with stomachs full of plastic.

We froze one fish whole, and the liver, two filets, and the gut content plastics from the dissected fish for analysis of persistent organic pollutants by colleagues in Bergen, Norway.

Currently, the lab is making a valiant attempt to process the two nets, but the sheer number of small plastic fragments to count, rinse, and dry will take hours. I'll have numbers and concentrations in tomorrow's report, but I expect the numbers to be higher than anything SEA has observed in the Atlantic or Pacific. Certainly we will not observe the eastern edge of this region of high plastics in the Atlantic on this trip.