Plastic marine debris
Wednesday, June 3, 2009 - 20:56
Name a major environmental concern -- and it is quite likely that the first thing that comes to mind is global warming, perhaps deforestation or endangered animals. How about plastic debris in the oceans? To most people, this is not on their top list of environmental crises, but in reality, the amount of plastics in our oceans is a major concern facing us today.
Captain Charles Moore, founder of the Algalita Marine Research Foundation -- an organization that spreads the word about the environmental concerns of plastic in our oceans -- sums it up best, "Our oceans are becoming the virtual garbage can for the developed and developing world."
So what exactly is marine debris? Basically, any manufactured or processed solid waste material that enters the ocean environment from any source is considered marine debris. And there is a lot of it floating out there in the oceans -- floating and sinking with the tides, or being washed ashore on beaches, or worse: being ingested by animals. It litters beaches all over the world, and all depths of the ocean (including the seafloor) -- making its impact one of global significance.
This is not a new problem. Historically, oceans have been used as dumping grounds for waste. The real problem, however, started when plastic began to enter the oceans -- and remained there forever. According to the United Nations Environment Programme, plastics comprise up to 90 percent of floating marine debris. About 6.4 million tons of plastic enter the oceans each year -- and this amount is significantly increasing each year. In fact, studies of the beaches and ocean bottom in California show that plastic materials are the most common type of human-made debris in this region.
This is not a problem that we are done with. We are in the middle of a great crisis -- a situation that does not seem to be improving anytime soon. As our dependency on plastic increases, so does the amount of plastic waste we produce. The more plastic waste we produce, the more of it ends up at sea. Within the past decade, plastic in the oceans has increased by two to three times each year. Our oceans can only hold so much -- what will we do after it's full?
"The sea is like a soup…and the stock is getting thicker..." (Captain Charles Moore).
This problem is not confined to one place. Studies show that plastic debris pollutes oceans worldwide. Because plastic is lightweight, it travels around the globe in ocean currents, often littering beaches far from where it was released. Oceanic gyres, which are circular ocean currents created by rotating high-pressure systems, have become huge accumulation zones for plastic debris. We only see plastic that floats—but since the specific density of plastic is close to that of ocean water, it can rise during rough seas and sink during the calms. Plastic is found throughout the water column: at the surface, below the surface, and, yes, even at the ocean bottom, trapped in sediment.
For example, in the North Pacific Gyre, a vast "cloud" of plastic debris has gathered throughout the years. According to Captain Charles Moore, the Pacific Garbage Patch is estimated to weigh 3 million tons and is about twice the size of Texas! This garbage vortex, as some call it, is made up mostly of fine plastic chips and is impossible to skim out of the ocean. Even more, other oceanic gyres have their own versions of the garbage patch, and together these areas cover about 40 percent of the ocean. "That corresponds to about a quarter of the earth's surface," Moore says, "So, 25% of our planet is a toilet that never flushes."
In fact, in the middle of the North Pacific Gyre -- miles from the nearest shore -- the plastic in a trawl sample outweighed the amount of living biomass (plankton) 6:1. Moreover, this was several years ago. Now, Moore predicts, the ratio must be around 30: 1. Horrific, but true!
"It seemed unbelievable, but I never found a clear spot. In the week it took to cross the subtropical high, no matter what time of day I looked, plastic debris was floating everywhere: bottles, bottle caps, wrappers, fragments -- and any attempt to remove that much plastic from the oceans? ...It boggles the mind. There's just too much, and the ocean is just too big." (Captain Charles Moore)
Plastic is forever. Except for the small amount that has been incinerated -- and it is a very small amount -- every bit of plastic ever made still exists.
Once plastic enters the oceans, it remains there forever until it is either ingested or deposited. Plastic does not biodegrade; rather, it "photodegrades" by sunlight into smaller and smaller brittle pieces -- yet, it remains completely plastic. Plastic is a polymer, and its molecular structure resists biodegrading. Even when broken down to a single molecule, it remains too tough to be degraded naturally. No one really knows how long it will take for plastic to biodegrade, or return to its carbon and hydrogen elements. We only invented plastic 144 years ago, and science's best guess is that its natural disappearance will take several more centuries. Meanwhile, we are churning out about 60 billion tons of it each year, most of which is used in products meant for a single use. Do we really want that ketchup bottle or discarded flip-flop to last forever? Plastic never really goes away...it stays forever.
"It’s not the big trash on the beach. It is the fact that the whole biosphere is becoming mixed with these plastic particles. What are they doing to us? We’re breathing them, the fish are eating them, they’re in our hair, they’re in our skin." (Moore)
This is a real crisis. And its effects are already clearly visible. As more and more plastic is dumped into the ocean, more and more of it finds its way in the ocean food chain. Small plastic particles bobbing in the water would look like an easy meal of plankton to many fish and birds. Plankton and plastic is found side-by-side in the water -- would even humans be able to tell the difference? Ingested plastic makes its way up the food chain, entering the bodies of larger and larger animals.
But the plastic ingested is not only the tiny pieces. Much larger plastic particles -- plastic pen caps, tubing, lids and even cigarette lighters have been found inside bird guts. Many species of albatross have been found to ingest plastic. The plastic easily slides down their throats, but once inside their bodies, it gets lodged. They cannot expel it out -- their food intake lessens, they dehydrate...and die.
Besides ingestion, marine debris can also kill wildlife in other ways. Many animals are strangled and become ensnared in it and drown. More than a million seabirds, 100,000 marine mammals and countless fish in the North Pacific die each year from either ingesting marine debris or being ensnared in it or drowning.
According to the California Ocean Protection Council, this situation doesn’t seem to be improving, "Despite global treaties to prevent dumping at sea and minimize land-based sources, and increasing efforts worldwide to protect water quality, the quantity of marine debris in the world’s oceans is increasing."
While at first it may seem as if ships that dump waste out at sea cause this plastic problem, in fact, an estimated 80 percent of the plastic in the ocean is from land-based sources, and only 20 percent comes from sea-based sources such as fishing and shipping.
"The ocean is downhill from everywhere. It's like a toilet that never flushes. You can't take these particles out of the ocean. You can just stop putting them in."
The only real solution to this problem, all sides agree, is to cut the problem off at its source: on land. The less plastic we use, the less plastic is dumped, and so less plastic finds its way out to the ocean.
Keep reading to find out how you can reduce your plastic usage!
Photos: www.saveourshores.org Kamilo Beach
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