In the Mariana Trench, the deepest part of the world, divers have found plastic bags and candy wrapping paper. In a recent may report by Scientific Reports, the findings of microplastics at different depths off the coast of California showed that plastic debris is most common a few hundred meters below sea level. Most of the plastic waste in the ocean comes from land, and rivers act like conveyor belts, carrying more and more garbage along the way down the river, eventually gathering into the ocean. Once in the ocean, much of the plastic waste remains in coastal waters; if it is caught by ocean currents, it can be transported around the world, including deep-sea waters that have not yet been widely explored by humans.
https://www.newsdeeply.com/oceans/articles/2017/10/09/report-microplastic-can-penetrate-fishs-brains-altering-behavior
Hundreds of millions of ocean plastics
Plastic pollution is ubiquitous in the oceans. Remote islands are "ideal" places to assess plastic pollution, as relatively independent islands provide an objective view of the volume and amount of plastic debris currently surrounding the globe.
Randi Rotjan, a research assistant professor and marine ecologist at Boston University, is the co-chief scientist of the Phoenix Islands Conservation Area in the central Pacific Ocean. Every time he visited, he had to travel by boat from Hawaii for seven days, where Rottga discovered that even in one of the most remote places on Earth, plastic waste was wrapped in samples they had taken from the surface of the ocean. "These are typical microplastics that float far away, where the closest person to us is on the International Space Station." Rottga said.
Scientists have found plastics and microplastics | in every part of the oceans they visit Image credit: exxpedition /lark rise pictures
This year, a survey of plastic pollution in Australia's Cocos (Keeling) Islands revealed that there were about 4.14 pieces of human-generated plastic waste scattered on the area's beaches, weighing a total of 238 tons, including plastic, foam, metal and glass, of which about 977,000 shoes and 373,000 toothbrushes were scattered.
Left: Cocos (Keeling) islands on Earth, by tubs; right: Satellite photo of the Cocos (Keeling) islands | by nasa
Micro-garbage (1-5mm) on the east side of South Island | Source: Jennifer Lavers
Dr Jennifer Lavers, who participated in the study, said that there is no large number of people dumping garbage near remote islands, so it can be used as an indicator of the amount of plastic waste in the global oceans. "We estimate that there are 414 million pieces of plastic debris on the Cocos (Keeling) Islands, with a total weight of 238 tons," she stressed. But this is only a conservative estimate, because we only sampled to a depth of 10 centimeters. ”
In fact, as early as May 2017, Dr. Lavers's research made headlines around the world, when she revealed that the highest density of plastic debris in the reported areas of the planet was the remote Henderson Island beach in the South Pacific. The study found that while the density of plastic debris on beaches in the Cocos (Keeling) Islands is lower than that of Henderson Island, the total amount dwarfs Henderson Island, which found 38 million pieces of plastic debris weighing 17 tons.
Garbage | on the island by dustan woodhouse, source: unsplash.com
The researchers sorted the plastic waste captured in the Cocos (Keeling) Islands and found that most of the identifiable plastic debris was mainly single-use plastic consumer goods, such as bottle caps, straws and a large number of shoes. Dr. Annett Finger of the University of Victoria, one of the study's authors, said global production of plastic products continues to increase, with nearly half of all plastic products produced in the past 60 years in the past 13 years. An estimated 12.7 million tonnes of plastic entered the ocean in 2010 alone, of which about 40% entered the waste stream in the same year they were produced [3].
Ocean plastic debris is also growing rapidly due to the growth of single-use plastic consumption, and it is estimated that the number is now 5.25 trillion. The threat of plastic pollution to wildlife is well documented, and its potential impact on humans is becoming a growing area of medical research [3].
Beneath the ocean surface, tiny pieces of plastic are piled up
When we think of plastics in the ocean, we tend to think of them floating on the surface of the water. In fact, far from it.
All this garbage breaks down into tiny particles that are barely visible to the naked eye and are called microplastics. In the last decade or so, scientists have begun to find plastics and microplastics in every part of the ocean they've ever been to. Microplastics are suspended at every depth throughout the ocean and are also buried on the ocean floor. They're more like spots of spices and seasonings spread across a bowl of soup than spots of fat that you can skim off the surface.
Now, the researchers have found that deep water, the main habitat for marine animals, contains more plastic pollutants than surface water. Shockingly, there are more microplastics deep in California's relatively clean Monterey Bay than in the infamous Pacific garbage dump.
Beautiful Monterey bay cc by-sa 3.0, https://commons.wikimedia.org/w/index.php?curid=971186
Monterey Bay, California, is known as one of the purest and most vibrant coastal ecosystems on earth. Once endangered otters now float in towering kelp forests – sea urchins like to eat kelp, otters like to eat sea urchins, so the number of sea otters in kelp forests has rebounded. Great white sharks visit from time to time, and a wide variety of whales and dolphins are also regular visitors... All in all, this is one of the greatest success stories in the history of marine conservation.
The researchers used unmanned miniature submarines to take samples from the surface of the sea all the way up to a depth of 1,000 meters. The sample area includes a site near Monterey Bay off the California coast and a site 15 miles offshore.[4] After sampling and analysis, it was found that the seawater here contains a large amount of microplastics. The team found microplastics in each depth of the seawater sampled, and the concentration of plastics was higher than in the Great Pacific garbage belt. The concentration of particulate matter at a depth of 1000 meters is about the same as that of 5 meters deep, with an average of about 3 particles per cubic meter. In water at depths of 200 to 600 m, plastics are more concentrated, containing 10 to 15 particles per cubic meter [5].
Signs of plastic weathering suggest that the plastic comes from land, not from local fishing nets — they've been floating for a long time. To figure out how the plastic spreads in the animals, the researchers studied pelagic red crabs and giant juvenile sea squirts — two filter-feeding species that underlie the ocean's surface and seafloor food webs.
Giant juvenile sea squirts are strange animals that use mucus nets to catch food and regularly discard their mucus nets — and the plastic that those nets collect — and sink into the water. The mesh sieves of juveniles, also known as pervasive sacs, are discarded after each feeding and sink to the ocean floor .[4-6] And when an ocean-going red crab becomes "someone's" lunch, it can carry microplastics from the deep sea to the ocean surface, says Anela Choy, a biology oceanographer at the Scripps Institute of Oceanography in California and co-author of the study, which may be spreading pollutants to other predators, from tuna to sea turtles.
The team collected 24 pelagic red crabs and 8 giant juvenile sea squirts, measured the viscera of the former and contaminants in the mucus filter of the latter, and confirmed the presence of microplastics. This means that every animal in the sample, some of which forms the basis of the Gulf food web, contains microplastics in its body.
Marine life feeds on tiny organic particles, such as giant larvae (left) and ocean-going red crabs (right), which can accidentally swallow microplastics | hundreds of meters below water Image source: scientific reports
To the researchers' surprise, most of the microplastics found at the contamination sampling sites did not come from fishing gear deployed around the bay, but from materials commonly found in single-use beverage and food containers. Scientists predict that the deep sea could be one of the biggest sources of plastic pollution on Earth. Although only two areas were sampled, the researchers believe they would find similar patterns in different oceans, taking into account ocean currents and constantly mixing seawater.
Single-use plastic products may become the biggest culprit
Since the mass production of plastics in the early 20th century, humans have produced about 830 million tons of plastic. About three-quarters of the plastic waste has been discarded, and 80% of it has been drifted into the environment or landfilled. An estimated 8 million tons of garbage are thrown into the sea each year, and an estimated 5.25 trillion pieces of plastic debris are now floating in the ocean due to the growth in single-use plastic consumption.
Examples from the Cocos (Keeling) Islands and Monterey Bay, California, show that single-use plastic pollution is becoming a major force in plastic pollution on the planet, and the harm to the oceans is particularly severe. And while we now have a broad understanding of marine pollution, addressing marine plastic pollution is an extremely complex challenge. The scale of hundreds of millions of tons of plastic waste means that cleaning up the oceans is impossible. Cleaning up beaches is time-consuming, expensive, and needs to be repeated regularly, as thousands of new plastics are washed up every day. The only viable solution is to reduce the production and consumption of plastics while improving waste management to stop the material from entering the ocean from the outset.
Plastic in the ocean is thought to have escaped the garbage management system, and there are many ways in which plastic enters the ocean. Many countries dump their garbage directly into the river. In countries where there is garbage collection, plastic escapes as it enters landfills and into landfills and then flows downstream. Even recycling isn't out of the woods – only 9% of the world's plastic is recycled. All this garbage is considered large plastics and ends up in the ocean. When they are soaked in seawater, worn away by the sun's ultraviolet rays, waves and wind, they become more harmful microplastics.
The best way to deal with plastic pollution in the oceans is to reduce the amount of plastic humans use on land. However, because human life and plastic are closely intertwined, it will take many efforts to change this situation.
Environmentalists argue that large industrial polluters have a responsibility to reduce their plastic footprint and come up with solutions such as compostable materials or new ways to reuse discarded plastics. In addition, standardizing the plastics used so that they are only suitable for a few types of recyclable plastics, and implementing a deposit return program, may also significantly increase recycling rates. Environmental advocates also advise consumers to minimize the amount of plastic they use in their lives — especially single-use plastics, like styrofoam cups that are thrown away after a single use. Plastic is a material that can be used permanently, so single-use doesn't make much sense.
The article is transferred from: Popular Science China Network