Oceanic Garbage Soup - Trash Trawling in the Pacific
02 February 2010
THE SEA OF GARBAGE
OCEANIC GARBAGE SOUP
TRASH TRAWLING IN THE NORTH PACIFIC
Floating on or just beneath the surface of the north Pacific Ocean over 1000 miles from any landmass lies a soup of trash; the Great Pacific Garbage Patch. Located in the North Pacific Sub-tropical Gyre that covers approximately 10 million square miles, it covers an area the two and a half times the size of France, the largest country in Western Europe, and is 20% larger than South Africa. Discovered in 1997 by Charles Moore, ironically an heir to a petroleum fortune, the GPGP is a mass of plastics, debris, and lost or discarded fishing nets.
Nearly 90% of all floating marine litter is plastic, a petroleum-based substance that takes decades to be broken down on land by the suns rays, and even longer in the cool seas where it is often further protected by barnacles and algae. Plastic pellets used in all sorts of packaging and plastic products are the most commonly found marine pollutant. Also known as nurdles or mermaids’ tears, 50 million tonnes are produced every year. 80% of marine rubbish comes from land via winds and rivers, with ocean currents carrying debris from the west coast of North America to the gyre in about five years, and debris from the east coast of Asia in a year or less. The remaining rubbish comes from ships with a typical 3,000-passenger cruise ship producing over eight tons of solid waste weekly, much of which ends up in the patch, alongside floats and other equipment illegally jettisoned from commercial and fishing vessels to avoid the cost of proper disposal in port.
Then there are the contents of the estimated ten thousand cargo containers that fall overboard every year. One container can hold 10,000 running shoes, 17,000 ice hockey gloves, or a million pieces of Lego. Given the number of consignments lost and the longevity of the products, there are hundreds of thousands, if not millions, of sports shoes floating in the seas. In fact the Garbage Patch name was coined five years before Moore’s discovery by Seattle oceanographer Curtis Ebbesmeyer whilst studying a consignment of 29,000 plastic bathtub ducks lost from a container ship during a Pacific storm. Using oceanic current modelling software and plotting the positions where ducks were found, he became aware of a slow vortex into which debris was drawn.
Unfortunately most of the trash is not brightly coloured ducks and running shoes, but mostly small plastic particles suspended at or just below the surface, making it detection by aircraft or satellite impossible. The U.N. Environment Program estimates that 46,000 pieces of plastic litter are floating on every square mile of the oceans whilst the GPGP contained at least six times more plastic matter than plankton biomass, the bottom of the food chain, when last surveyed.
Returning from a trans-Pacific yacht race, Moore decided to try a short-cut through the virtually windless and therefore seldom crossed North Pacific Sub-tropical Gyre. Motoring through the area Moore was shocked by the contents of the sea. "Every time I came on deck, there was trash floating by," he said. "How could we have fouled such a huge area? How could this go on for a week?"
As the founder of the non-profit Algalita Marine Research Foundation he began looking into the sources of the problem and its extent. In 1999 he returned to undertake the first scientific sampling of the area he describes as two to three times the size of Texas, but that he fears could be greater than the surface area of the United States.
In June 2009, with Moore on board for his tenth mission to the area, the ORV Alguita set off on the a four-month mission to gather more data to try to gain further understanding into the wide ranging and poorly understood potential impacts of oceanic micro-plastic pollution.
The first leg of the trip concentrated on sampling the area around Hawaii providing both water samples from trawls and fish tissue samples for analysis back on land. It is believed that a significant amount of the plastic pollution currently cycling around the North Pacific passes around or through the Hawaiian islands making the area a suspect for high concentration of small particle pollution as well as large ghost net pollution. The importance of these islands, with their pristine reef ecosystems, for a myriad of species means that a full understanding of how these animals and their environment are interacting with plastic pollution is needed.
The trip home from Hawaii back to California was a key element in calculating the rate of growth of the Great Pacific Garbage Patch, included a resampling of the original 1999 gyre crossing. The 10-year gap will provide concrete figures about the rate of growth and about the seasonal changes in plastic density as the 1999 trip data will be significantly strengthened by a summer sampling of the same transects. By comparing the levels found ten years ago, and using model predictions, growth over that period can be calculated. Using trawling techniques and sampling methodology developed by the Algalita Marine Research Foundation for the 1999 sampling, amount of fish caught, with a particular interest in the family Myctophidae (lantern fish), will be compared with the data from the catch during the winter transect run in February 2008, thus for the first time assessing the load of Persistent Organic Pollutants (POPS) in their tissues.
The 2008 expedition discovered the widespread ingestion of plastic particles by fish that forage on plankton at night on the ocean surface. In trawls a total of 660 fish, representing six species, were captured for future study. 35 percent of these fish had ingested micro-plastic particles, the record holder having 83 fragments.
This data poses further questions that data from the 2009 expedition will shed light on. Plastics absorb Persistent Organic Pollutants (POPs) from paint chips, coolants, pesticides, and metals, so when fish eat plastic matter and then bigger fish eat them, the chemicals could be bioaccumulating. Do the micro plastic particles contain POPs, and do these harmful pollutants migrate into the tissues and organs of the fish that ingest them and subsequently enter into the human food chain? Concentrations of the most frequent POPs (PCBs, DDT, and PAH – all renowned for their effects on the human organism) on nurdles collected from Japanese coastal waters were found to be up to 1 million times higher than the levels detected in surrounding seawater, the new data from the NPSG could have far-reaching effects.
Ingestion of plastic items kills an estimated 100,000 marine animals yearly as plastic mistaken for food fills the stomach and impedes digestion of proper nourishment. According to Pulitzer Prize-winner Kenneth Weiss’s research, young Albatrosses are killed in their hundreds of thousands, and corpses on Midway Island have been found with all sorts of plastic matter in their stomachs, including ballpoint pen lids, toy soldiers, dinosaurs, perfume bottles, highlighter pens, and disposable lighters.
Albatross are by no means the only victims. An estimated 1 million seabirds choke or become tangled in plastic nets or other debris every year. About 100,000 seals, sea lions, whales, dolphins, other marine mammals and sea turtles suffer the same fate. Furthermore, buoyant micro plastic particles ingested by small deep-sea fish may negatively impact their ability to return below and to exist in their normal habitat.
Although the actual analysis of the samples will take up to six months, visual observation comparing photos of the worst trawl in 1999 to the lightest in 2009 showed that the accumulation has not only a higher concentration of micro plastics but, according to Captain Moore, there was a record number of macro plastics. Things like parts of buoys, crates, bottles, caps, plastic popsicle sticks, umbrella handles, numerous oyster spacers, and builders’ hard hats were often found or observed floating on the surface.
On the last leg, the six crew members collected samples using a manta trawl with a rectangular opening of 0.9×0.15 m2, and a 3.5 m long, 333u net with a 30×10 cm2 collecting bag at a speed of 2.5 knots for an hour at a time, taking 52 samples. Sampling concentrated on the surface, where most of the items were found just below the surface tension with only a small part breaking the surface such as 55-gallon drums. There were items full of air like buoys and capped bottles that floated on the surface but above all location in the water column depends on sea state. If the ocean is rough, the trash is forced down deeper. When it is calm, it rises toward the surface again, although Captain Moore, the only crewmember remaining from the 1999 sampling expedition, has found plastics over 100 metres deep using a bongo trawl. Every sample came back with large quantities of plastic particulates. Though it’s difficult to quantify just how much more without the data from the samples, according to Captain Moore it appears to be significantly more.
Researcher Bonnie Monteleone from the University of North Carolina said that the most shocking thing for her was “finding everyday house hold items like bottles and plastic containers that were half eaten or had large bite marks in them. Fish are eating the plastic. It might not be the fish that we eat that are eating the fish, but I can assure you the fish we eat are eating the fish that are eating the plastic”.
She became nauseated. “After witnessing the first few samples I thought, “Yep, that’s why I’m out here.” But after the 20th trawl, I began hoping the sample would come back free of plastic, “Shouldn’t there be just one that doesn’t have plastic in it?” But to no avail. I have to wonder if there is anywhere on this planet we haven’t polluted”.
One major difference to 1999 was that the amount of large items that were navigational hazards. Ghost nets that barely break the surface so it is difficult to see them until you are upon them. They can weigh up to 500 kilograms or more. “We managed to remove one that was around 200 lbs. If we had run into it, it could have done serious damage” said Ms Monteleone. The crew also had a near miss with a telephone pole which came within a few feet of the starboard pontoon. There was also a large item strapped to a wooden pallet that was about 3 feet square that they dared not approach too closely. The props were fouled several times with derelict fishing gear and went so far as to stop the engines in the middle of the night. Crewmember Jeff Ernst had to free dive under the boat to disentangle them. Even though there are no common shipping lanes nor cruise lines and very little if any fishing occurring near or in the GPGP, there is evidence of our negative plastic influence everywhere.
What can be done about it? For the matter than is already in the GPGP, very little. Collecting it and disposing of it would be a monumental exercise that no government would be willing to fund, unless it were to start having tangible negative effects on human health.
The NPSG is one of five major oceanic gyres around the world, and there is mounting evidence that equivalent levels of pollution will be found there. It would appear that the only answer is to stop more plastic from getting into our oceans, but in a society ever more reliant on non-biodegradable substances, that may be a task as big as the Garbage Patch itself.