Scientists are getting a better handle on how much plastic we put into the oceans and what effects it’s having.
Tallying tons of ocean plastic. I’m Bob Hirshon and this is Science Update.
From the single-use packages and utensils we throw away to fishing nets lost at sea, humans put huge amounts of plastic into the oceans. How much? Well, marine scientist Marcus Eriksen and his colleagues report in the journal PLoS ONE that just the plastic floating on the ocean surface comes to nearly 270,000 metric tons, most of it in the form of tiny microplastic particles that filter-feeding marine animals consume.
Plastic’s a great sponge for similar hydrocarbons, like industrial chemicals, PCBs, pesticides, DDT; it’s almost like microplastics are delivery systems for toxins to enter marine food webs.
Eriksen says that solving the problem will require managing plastics from manufacture to the end of their lives—to ensure they don’t add to the islands of plastic already in our waters. I’m Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
Think about what you ate for breakfast today. What was it? What did you use to eat it? Even if you ate breakfast at home, chances are that the food you ate came in something diposable—a carboard box, plastic milk jug, or even an egg carton made out of paper or plastic. If you ate breakfast at work or school, you may have used plastic utensils.
What happens, though, to all of these disposable items once we're done using them? Unfortunately, only about 5–10% of the plastic items we use get recycled and about 50% end up in landfills. The rest is unaccounted for but often makes its way to the sea. Plastic pollution is found in all of the world's oceans. Ocean currents throughout the globe converge in five large gyres (large systems of rotating ocean currents), and it is often in these gyres that researchers find plastic garbage patches.
Plastic waste in our oceans and waterways is the focus of the research conducted by Marcus Eriksen and his colleagues. They have found that the plastic polluting our water is not just the large pieces of plastic that can be seen floating on the surface, but also tiny pieces that measure less than ¼ inch across. According to Eriksen, 44% of all seabird species, 22% of cetaceans, all sea turtle species, and a growing list of fish species have been documented with plastic in or around their bodies.
Both kinds of plastic can be hazardous to marine organisms, as explained by Eriksen in the audio clip. The large kinds, like plastic bags or drifting nets, can be ingested by marine organisms or entangle birds, fish, and mammals. The smaller kinds, however, can absorb waterborne contaminants such as PCBs, pesticides, and many hydrocarbons washed through our watersheds. These pollutants could then transfer to the organisms that eat them.
In addition to concern about plastic's effects on marine life, scientists are concerned about its potential human health effects. Do chemicals in the plastic get into the tissues of animals that eat the plastic? If so, do they work their way up the food chain? More research will need to be done to answer those questions.
Now try and answer these questions:
- How much plastic waste gets recycled and how much ends up in landfills?
- Why do you think so much plastic waste is unaccounted for? Where do you think it goes?
- What is a gyre?
- Why are scientists concerned about the plastic found in the ocean?
- How can the ocean plastic harm marine organisms?
Listen to Litter Life to learn about another way ocean plastic can affect the marine environment.
In Killifish and Pollution, hear about how certain small fish are managing to survive in highly toxic waters.
You can help your students learn more about marine ecosystems and oceans by leading them through these two lessons:
- Marine Sanctuaries helps students develop an understanding of diverse marine ecosystems and the problems they face.
- Oceans helps students obtain a better perception of earth's oceans and to understand earth's water cycle.
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