Throughout our world’s oceans hides a silent killer – plastics. These organic compounds are a nuisance to the oceans and are now considered a big threat to the marine ecosystem. Plastics are making their way into the oceans via rivers, storm water runoff, transport of land waste by wind, or wastewater discharges every day. Today, roughly 60-80% of the world’s litter comprises plastic and around 10% of the annual plastic production ends up in the oceans.
For marine life, the primary impact of plastics in oceans are from ingestion or entanglement. The entanglement of marine creatures, particularly fish, turtles, and mammals has often been described in many articles and books as a serious mortality factor. Entanglement can lead to drowning, suffocation or strangulation. Ingestion of plastics by creatures such as sea turtles, seabirds, zooplankton, cetaceans, whales, seals, and other marine animals may lead to blockage of the digestive tract leading to starvation. Entanglement or ingestion of plastics can also affect feeding capacity and digestion, leading to malnutrition, diseases, improper reproductive functioning, and reduced growth rates and longevity.
Recently, the accumulation and consequences of microplastic particles in oceans have been recognized as an emerging threat to marine life as well as the environment. Microplastics are small plastic particles or fragments with a diameter less than 5 mm which come from a variety of sources such as cosmetics, clothing, and industrial processes. Their concentration has been increasing over time due to plastic degradation. Solar radiation, abrasion, and water and wind movements cause plastic debris to break into smaller bits without any chemical degradation. They are ingested by marine creatures and are transferred through the trophic chain. Therefore, they are a cause of great concern for the world. Microplastics are a threat not only for their size but also due to their ability to absorb persistent organic pollutants (POP), which differs according to various polymers.
Recently, researchers at the Alfred Wegener Institute of the Helmholtz Center for Polar and Marine Research in Germany found up to 12,000 pieces of microplastics per liter of sea ice trapped in the Arctic Ocean. Surveying five regions in the area, they found the latest trash volume to be thrice more than previous studies. Around 1 ton of plastic pieces was frozen in the Arctic ice, based on results of previous studies.
The microplastics concentration in the Arctic Ocean concern experts as they pose near-permanent contamination. “The high microplastic concentrations in the sea ice can not only be attributed to sources outside the Arctic Ocean. Instead, they point to local pollution in the Arctic,” said study author Dr. Ilka Peeken. According to the study, the record levels of trash fragments in the Arctic come from the huge garbage patch in the Pacific Ocean.
Recently, microplastics have also been discovered by CSIRO scientists in ocean-floor sediments 2 km below the surface in one of Australia’s marine environments. The pieces were discovered while analyzing samples taken hundreds of kilometers offshore at the bottom of the Great Australian Bight, a pristine biodiversity hotspot. According to conservationists and scientists, the discovery of the South Australian coast should alert governments and corporations to omit the unnecessary use of plastics and to legislate and incentivize to tackle the growing ocean plastics problem.