Sep 27

The first traces of plastic debris have been found in the once pristine environment of the Southern Ocean, according to a new study.

Photo of small icebergs in Esperanza Bay, Antarctica

View of the Antarctic, in the Southern Ocean

The findings come after a 2.5-year, 70,000-mile voyage by the French scientific research vessel Tara, which has been sailing the world’s oceans to investigate the impacts of climate change.

Samples from locations in the Southern Ocean and Antarctica revealed traces of plastic waste at a rate comparable to the global average. This came as a surprise to the researchers, who had expected levels some ten times lower.

Discovering plastic at these very high levels was completely unexpected because the Southern Ocean is relatively separated from the world’s other oceans and does not normally mix with them,” said Chris Bowler, scientific co-ordinator of Tara Oceans.

Photo of southern rockhopper penguin, E. c. chrysocome, colony in typical habitat

The Southern Ocean is rich in wildlife, from penguins and fish to seals and whales

Fatal impacts

In addition to large items of waste, such as plastic bags, bottles and other plastic items, the world’s oceans also contain microscopic fragments that result from the degradation of larger items through years of exposure to seawater and sunlight.

The researchers were surprised to find that synthetic fibres, largely made up of clothing residues from washing machines, also comprised a significant portion of the plastic fragments they found.

Plastic pollution has many long-lasting and even fatal impacts on marine life. Birds, fish and other animals are known to regularly consume plastic waste, mistaking it for jellyfish or other prey, but it cannot be digested and remains in the stomach. Plastics also slowly release toxins and other chemicals, which can build up in the food chain.

Photo of dead Laysan albatross showing plastics in stomach

Dead Laysan albatross showing plastics in stomach

Human impacts ‘truly planetary’

Although it is difficult to identify the main source of the waste in the Southern Ocean, much of it is thought to originate from Africa, South America or Australia. Sadly, the fact that plastic debris has reached the Southern Ocean shows that our throw-away culture now has impacts around the globe.

Talking about the findings in the Southern Ocean, Chris Bowler said, “We had always assumed that this was a pristine environment, very little touched by human beings. The fact that we found these plastics is a sign that the reach of human beings is truly planetary in scale.”

Photo of green turtle feeding on jellyfish

Green turtle feeding on jellyfish. Turtles and other species often mistake floating plastic bags for prey.

Action against plastic waste

According to Bowler, it is too late to do much about the plastic already circulating in our oceans, as it will take thousands of years to degrade. However, we can take action against future pollution, for example by advocating the use of biodegradable materials and by changing consumer attitudes and behaviour.

The research ship Tara will continue its marine research in 2013, when it will travel to the Arctic to investigate the impacts of melting sea ice, a result of global climate change.

Read more on this story at The Guardian – Plastic debris reaches Southern Ocean, previously thought to be pristine.

Find out more about plastic waste with ARKive’s new teaching resource for 11 to 14 year olds: Human Impacts on the Environment.

Watch a video about the impact of plastics on the Laysan albatross.

Liz Shaw, ARKive Text Author

May 9

The amount of plastic waste floating in the northeast Pacific Ocean has increased a hundredfold in the past 40 years and is altering marine habitats, according to new research.

Photo of a puffin mistaking plastic for food to provide to chick

Puffin mistaking plastic for food to give to its chick

Scientists from the Scripps Institution of Oceanography recorded the huge rise when trawling the waters off California as part of the Scripps Environmental Accumulation of Plastic Expedition (Seaplex) in 2009.

In a study published in the journal Biology Letters, the researchers were able to compare the amount of plastic found with data stretching back to the 1970s.

‘Great Pacific Garbage Patch’

Plastic waste is an ongoing concern for the world’s oceans. All plastic waste in the ocean that does not sink is eventually broken down into small particles – termed ‘microplastics’ – by the action of sunlight and waves. Plastic pollution has been observed in oceans around the world, and is already known to affect wildlife at an individual level. Fragments of plastic can be ingested by animals, while larger pieces can also cause entanglement.

Photo of a Laysan albatross fledging with neck caught in plastic coathanger

Plastic waste also entangles wildlife, such as this Laysan albatross fledgling caught in a plastic coat hanger

In the North Pacific Ocean, the natural circulation of the water, known as the North Pacific Gyre, tends to cause debris to accumulate in what has commonly become known as “garbage patches”. In the central North Pacific, a large patch of this plastic debris is often referred to as the “Great Pacific Garbage Patch”.

The current research follows another recent study which showed that 9% of fish collected off the Californian coast had plastic waste in their stomachs. Published in the journal Marine Ecology Progress Series, the study estimated that fish in the North Pacific Ocean could be ingesting as much as 12,000 to 24,000 tonnes of plastic a year.

Photo of a dead Laysan albatross showing plastics in stomach

Dead Laysan albatross showing accumulation of ingested plastics in its stomach

Ecosystem effects

Although the toxicity of plastics and the problem of ingestion by marine animals are obvious concerns, the researchers say that the broader effects of plastics on marine ecosystems also need to be examined.

They studied the association between plastic fragments and the marine insect Halobates sericeus, a relative of the common pond skater. Known as a “sea skater” or “water strider”, this species feeds on plankton and fish eggs, and in turn is prey for seabirds, fish and turtles.

Photo of a common pond skater walking on water

The common pond skater, a relative of the sea skaters used in the study

The sea skater requires hard platforms on which to lay its eggs, usually using floating debris such as seabird feathers, shells, lumps of tar or even pumice rock. However, the scientists found that the numerous pieces of plastic now floating in the Pacific have provided the insect with new surfaces on which to lay its eggs, leading to a rise in its numbers.

We thought there might be fewer Halobates if there’s more plastic – that there might be some sort of toxic effect. But, actually, we found the opposite. In the areas that had the most plastic, we found the most Halobates,” said Scripps researcher Mirian Goldstein, the lead author of the study.

So, they’re obviously congregating around this plastic, laying their eggs on it, and hatching out from it. For Halobates, all this plastic has worked out well for them.”

Photo of a common hermit crab in plastic cap

Common hermit crab using plastic cap

Profound changes

The increase in the density of sea skaters could potentially have consequences for other marine species, including those that prey on the insect and its eggs. The increase in its numbers could also impact the zooplankton and fish eggs on which it feeds.

By introducing hard substrates to an area in which they are naturally rare, microplastics could therefore have broad impacts on entire ecosystems.

The study raises an important issue, which is the addition of hard surfaces to the open ocean,” said Ms Goldstein. “In the North Pacific, for example, there’s no floating seaweed like there is in the Sargasso Sea in the North Atlantic. And we know that the animals, the plants and the microbes that live on hard surfaces are different to the ones that live floating around in the water. So, what plastic has done is add hundreds of millions of hard surfaces to the Pacific Ocean. That’s quite a profound change.”

Read more on this story at BBC News – Big rise in North Pacific plastic waste and the Scripps Institution of Oceanography press release.

Explore ARKive’s threatened marine species using Google Earth.

Watch an ARKive video of a loggerhead turtle hatchling trying to eat floating plastic.

Liz Shaw, ARKive Species Text Author


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