(The Gist of Science Reporter) Plastic in the oceans   [JUNE-2018]

(The Gist of Science Reporter) Plastic in the oceans


Plastic in the oceans

People across the world need to stand together and say no to plastic if we have any hope of reducing the amount of plastic polluting the marine environment

Plastic in marine ecosystems is an environmental issue that has affected every country in the world, even the remotest shores uninhabited by humans, making it one of the biggest environmental challenges we face today.

Plastic not only looks unsightly, it maims and kills marine life, and poses a serious threat to entire population of many marine species. It also poses a health risk to humans. Scientists have warned that there will be more plastic than fish in the ocean by 2050 unless a concerted effort is made to reduce our dependence on single-use plastic items such as plastic bottles and plastic bags. It is now time for us to take immediate action and to create public awareness of 'ust how dire the situation is.

Where do they come from?

Marine plastic debris originates from two sources: Land-based sources and Ocean-based sources.

Land-based sources, including litter left behind by beachgoers and plastic that is washed into the ocean via rivers or blown in from the land, accounts for 80 % of the total volume of marine debris found in our oceans.

Ocean-based sources, including garbage dumped at sea by oceangoing vessels and fishing debris for example, fishing line, fishing nets, bait box strapping and other discarded fishing gear -accounts for 20% of marine debris polluting our oceans.

Since the mid-19008, the use of plastics to manufacture goods has dramatically risen largely because it is cheap, durable, and therefore longlasting ~a trait which unfortunately leads to it persisting in the environment. For a very long time! According to the marine plastic awareness group, “Plastic Ocean” , every year the world produces 300 million tonnes of plastic, half of which is used to manufacture disposable single-use items. Consequently, every year over'8 million tonnes of plastic is added to the ever-growing scourge of plastic accumulating in the ocean from years before. Once this plastic ends up in the ocean it doesn’t simply go away.

Around 90% of all marine debris is composed of plastics and Styrofoam (polystyrene foam), with food and beverage packaging being one of the most widespread items commonly found during coastal surveys of beaches around the world. Because of its lightweight characteristics, it is readily blown into rivers or directly into the ocean.
While only making up a relatively small percentage of the total amount of plastic in the ocean, discarded fishing gear is highly destructive. Abandoned fishing nets drift about endlessly in the ocean, effectively ‘ghost fishing’ ---indiscriminately trapping marine organisms that haplessly swim into them. Discarded fishing line can entangle birds, turtles and other marine life while larger marine animals such as seals are vulnerable to being ‘noosed’ by bait box strapping that has been slipped off bait boxes rather than cut off.

These tiny microplastics are washed down the drain, making their way to wastewater treatment plants. But because wastewater treatment facilities do not have filters fine enough to remove these micro-particles, they are discharged into rivers with the treated effluent, eventually making their way to the ocean.

Other sources of microplastics include tyre dust; paints, including road paint, building paint and marine paint; and accidental spills of microplastic pellets that are used to manufacture plastic products.

Buying ‘mineral’ water? Microplastics have also been found in more than 90% of bottled water samples tested. A study of bottled water conducted by Sherri Mason and her colleagues from the State University of New York at Fredonia, who tested 259 bottles of water from nine countries, including India, found an average of 325 microplastic particles per litre of bottled water. This is twice the amount found in their previous study conducted on tap water. The researchers conclude that the contamination is originating from the plastic bottles the water is packaged in or the bottling process itself.

Why is it important?

According to a 2015 Worldwatch Institute report, between 10-20 million tonnes of plastics end up in the world’s oceans every single year. As a result, there are around 5.25 trillion bits of plastic currently drifting around our oceans. This causes massive financial losses, estimated to be in the region of $13 billion annually, resulting from the negative impact that plastic debris has on marine ecosystems, the economic losses suffered by the tourism and fishing sectors, and the financial cost associated with coastal cleanups.

According to Greenpeace’s 2006 report: “At least 26 7 different species are known to have suffered from entanglement or ingestion of marine debris including seabirds, turtles, seals, sea lions, whales and jish. The scale of contamination of the marine environment by plastic debris is vast. It is found floating in all the world ’s oceans, everywhere from Polar regions to the Equator. Plastic bags resemble jellyfish when submerged underwater. As a result, turtles often ingest them, mistaking them for food. Other forms of plastics break down into tiny pieces which tend to float on the surface or be suspended in the water column, where they may be mistaken for edible morsels of food by marine creatures or surface feeders such as fish or seabirds. Discarded plastic items and bits of plastic of various sizes are ingested by seabirds, who feed them to their still developing chicks, which ultimately causes the chicks to die of malnourishment as they are not receiving any true sustenance, but rather just bits of plastic. This can affect the the survival rates of chicks in seabird colonies, and can ultimately 'ause entire population of decline.

According to the Ocean Conservancy’s International Coastal the survival rates of chicks in seabird colonies, and can ultimately 'ause entire Cleanup 2017 Report, during the 2016 International Coastal Cleanup.

1,066,644 pieces of polystyrene foam and 1,212,602 pieces of plastic less than 2.5 cm in size were collected from beaches across the world. In total, more than 2 million bits of foam and plastic were collected during this one beach cleanup event --imagine how much more went undetected on beaches that were not covered in this cleanup.

Because plastic pellets and Styrofoam beads are not readily digested, they accumulate within the digestive tracts of marine organisms that ingest them, causing the animal to feel satiated. As a result, the animal stops foraging for food and becomes more and more emaciated before eventually dying of starvation. The accumulation of plastic in the gut can also block the digestive system, resulting in the animal’s death even if it is getting enough food to eat. When predators higher up the food chain feed on an organism that has a digestive tract filled with bits of plastic and styrofoam, these undigested plastics are ingested by the preaat' , who also struggles tc digest it.

Persistent organic pollutants such as DT and PCBs -both harmful endocrine disrupters -can accumulate on the surface of plastics at concentrations that are hundreds of thousands or even a million times higher than concentrations naturally occurring in seawater. These pollutants are stored in the fatty tissue and organs of the body and get passed on up the food chain, becoming more and more concentrated in animals at the top of the marine food webs. Consequently, the ocean’s apex predators become more and more contaminated over the course of their lifetime as they continue to ‘ ey on contaminated organisms.

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Courtesy: Science Reporter