Ocean has been a dumping ground for plastic, industrial and chemical waste and sewage and this problem has been going on for generations. It has been treated as the world's largest landfill site rather than as a valuable resource. The Introduction of toxic materials such as plastic oils, chemicals, agricultural waste and industrial waste into the ocean water is referred to as Ocean pollution. It is concerning for health, environment and economic reasons.
Before the advent of plastic, the amount of ocean waste was small. Human impact on the ocean is called marine pollution,
which means waste ends up in the ocean causing adverse effects. In the 1960s, ocean dumping has been majorly resorted, plastic pollution was not a major pollutant of that time, it was chemical industries and sewage waste. In the 1970s, plastic and microplastic pollution seemed evident. There have been legislative attempts to de-pollute the Ocean and plastics from our waterways, plastic resin identification codes have been developed but still, there is a lot that has to be done.
Impact on various countries and aquatic lives
Ocean pollution is a growing problem in today’s world which impacts aquatic lives as well as humans. 8 million tonnes of plastic is dumped into the ocean every year which causes irreparable damage to marine organisms. Each year 100 million marine life is lost from plastic waste.
By 2050, there will be more plastic than fish in the ocean.
Impact on aquatic lives :
Entanglement – Marine animals like seals, dolphins, and whales, get entangled in discarded fishing nets which can lead to injury and death.
Ingestion – Seabirds fed plastic delicacies to their chicks who mistake floating rubbish for fish. Many chicks don’t even make it to adulthood. According to a study, plastics are found in 98% of Albatross.
Marine debris – It’s a huge concerning issue. Over 700 species worldwide are adversely affected by marine debris. Toxic chemicals like oil spills suffocate aquatic organisms. It’s a major cause of cancer and infertility in animals.
Microplastics – Plastics entering into the ocean don’t biodegrade but get fragmented by photochemical processes, resulting in the formation of Microplastics or MP (< 5mm) and sometimes Nanoplastics (< 1um). It absorbs toxic floating chemicals in the marine environment and provides a surface for growing microorganisms.
These small particles are ingested by animals right down at the bottom of the food chain as far down as zooplankton. That’s where plastics enter the food web. It is estimated that fish in the North Pacific now consume up to 24000 tons of plastic a year.
As one predator eats another, contaminants biomagnify. The most vulnerable animal to the effects of toxic plastic is the one at the very top of the food chain, exactly – HUMANS.
“What goes in the ocean, goes in you.”
Microplastics reduce fertility and survival in copepods and so can affect humans. Recent research showed the presence of MP in the human placenta. However, there is no clear evidence of its effect on humans.
If you are a seafood consumer, then ocean pollution has direct relevance to you.
Sea turtles – Mistake plastic bags for jellyfish. Plastic debris gets covered with algae and starts to smell like food. These contaminants leach out into the bloodstream and get incorporated into the tissues. 50% of sea turtles die due to starvation as their digestive tracts become clogged by plastics.
Mercury – Absorbed by fishes such as tuna, and causes neurological damage to fishes. Consumption of such fish increases the risks of brain and heart disease.
Oxygen depletion – Increased concentration of nitrogen and phosphorus promotes algal blooms in the ocean, this leads to oxygen depletion and creates dead zones.
Impact on countries :
● Several countries lack proper waste management systems to prevent plastic pollution such as sanitary landfills, recycling capacity, and proper waste disposal. This leads to global issues of plastic leakage into the ocean that further damage the ecosystem.
● Countries dependent on seafood are more prone to coastal water contamination. 250 million cases of human diseases are recorded annually.
● People of Canadian, the Arctic and Greenland are found to be contaminated by persistent organic pollutants (POPs).
● Blood contamination has been found in the population of East Greenland.
● Economic loss – 100s of millions of dollars are lost due to ocean pollution hazards.
● Exposure to polluted sea foods has been linked to causing Parkinson’s, and Alzheimer’s disease.
Formation of microplastics and food web contamination :
Every single person on our blue planet is connected to the Ocean. That means the choices we make can have a positive or negative impact on the Ocean.
Negative Human Effects
Habitat Destruction
Virtually all Ocean habitats have been affected in some way via drilling or mining, dredging for aggregates for concrete and other building materials, destructive anchoring, removal of corals and land “reclamation”.Coastal ecosystems are being particularly damaged by humans. Significant habitat loss is occurring particularly in seagrass meadows, mangrove forests and coral reefs, all of which are in global decline due to human disturbances.
Coral reefs are among the more productive and diverse ecosystems on the planet, but one-fifth of them have been lost in recent years due to anthropogenic disturbances. Coral reefs are microbially driven ecosystems that rely on marine microorganisms to retain and recycle nutrients in order to thrive in oligotrophic waters. However, these same microorganisms can also trigger feedback loops that intensify declines in coral reefs, with cascading effects across biogeochemical cycles and marine food webs. A better understanding is needed of the complex microbial interactions within coral reefs if reef conservation has a chance of success in the future.
Carbon Emissions
Since the industrial revolution, humans have increased carbon dioxide in the atmosphere to levels that have caused Ocean acidification and Ocean warming, amongst other climate related negative effects.
Chemical Pollution
There have been many disastrous chemical spills at sea and from industry on land, affecting animals immediately via ingestion, or long term, in changes to reproduction cycles and other biological processes.
Oil Spills
Sadly, oil spills still occur, coating beaches, sinking to smother Ocean plant life and killing a wide variety of birds, fish and sea mammals.
Noise Pollution
Research shows that underwater noise from construction, shipping and naval vessels significantly impacts the natural behaviour of cetaceans and many other marine species. This can be seen when mass beaching events occur or breeding success is diminished.
Plastic pollution
The world has woken up to the millions of tonnes of plastic that have entered the Ocean over the past 100 years. The impacts of this scourge will last a lot longer.
Over 300 million tons of plastic are produced every year, half of which are used in single-use products like cups, bags, and packaging. At least 14 million tons of plastic enter the oceans every year. It is impossible to know for sure, but it is estimated that about 150 million metric tons of plastic exist in our oceans. Plastic pollution makes up 80% of all marine debris from surface waters to deep-sea sediments. Because plastics are light, much of this pollution is seen in and around the ocean surface, but plastic trash and particles are now found in most marine and terrestrial habitats, including the deep sea, Great Lakes, coral reefs, beaches, rivers, and estuaries. The most eye-catching evidence of the ocean plastic problem is the garbage patches that accumulate in gyre regions. A gyre is a circular ocean current formed by the Earth's wind patterns and the forces created by the rotation of the planet. There are five main ocean gyres: the North and South Pacific Subtropical Gyres, the North and South Atlantic Subtropical Gyres, and the Indian Ocean Subtropical Gyres. There are significant garbage patches in each of these.
Larger plastic waste can be ingested by marine species, filling their stomachs and leading them to believe they are full when in fact they have taken in nothing of nutritional value. This can bring seabirds, whales, fish, and turtles to die of starvation with plastic-filled stomachs. Marine species can also be suffocated or entangled in plastic garbage.
The biggest threat of ocean plastic pollution comes from microplastics. These are small fragments of plastic debris, some of which were produced to be this small such as microbeads. Other microplastics come from the weathering of larger plastic waste. Once larger pieces of plastic waste enter the ocean, or any waterway, the sunlight exposure, temperature, humidity, waves, and wind begin to break the plastic down into pieces smaller than five millimetres long. Plastics can also be broken down by smaller organisms that will eat plastic debris, breaking it down into small pieces, and either excrete these microplastics or spit them out. In lab tests, it was found that amphipods of the species Orchestia gammarellus could quickly devour pieces of plastic bags, shredding a single bag into 1.75 million microscopic fragments. Although plastic is broken down, it is still a man-made material that does not biodegrade. It is estimated that approximately 90% of the plastics in the pelagic marine environment are microplastics. These microplastics are frequently consumed by marine organisms at the base of the food chain, like plankton and fish larvae, which leads to a concentration of ingested plastic up the food chain. Plastics are produced with toxic chemicals entering the marine food chain, including the fish that some humans eat.
Microplastics among sand and glass spheres in sediment from the Rhine. The white bar represents 1 mm.
Vast plastic garbage patches have accumulated at the centre of ocean gyres.
OvModel results for the count density of small planktonic plastic particles.
Red: denser
Green: less dense
Interactions between marine microorganisms and microplastics
Overfishing
In many areas, factory fishing has destroyed local fish stocks, leaving too few adults to breed for the future. Overfishing is occurring in one-third of world fish stocks, according to a 2018 report by the Food and Agriculture Organization of the United Nations.[9] In addition, industry observers believe illegal, unreported and unregulated fishing occurs in most fisheries and accounts for up to 30% of total catches in some important fisheries.[10] In a phenomenon called fishing down the food web, the mean trophic level of world fisheries has declined because of overfishing high trophic level fish.
Destructive Fishing
Certain fishing practices not only contribute to the overfishing of their target species but also damage the environment by dredging the seabed or catching other species that are thrown back dead.
Surface runoff
With increased urbanisation, tarmac and other manmade land surfaces contribute to petrol, diesel and other harmful chemicals easily flowing into rivers or directly into the Ocean.
Deoxygenation
The increase in the use of fertilisers for agriculture and warming ocean waters has contributed to the eutrophication of the Ocean in certain areas of the world. This means there is less available dissolved oxygen for native sea life, which can negatively impact biological processes.
Ocean deoxygenation is an additional stressor on marine life. Ocean deoxygenation is the expansion of oxygen minimum zones in the oceans as a consequence of burning fossil fuels. The change has been fairly rapid and poses a threat to fish and other types of marine life, as well as to people who depend on marine life for nutrition or livelihood. Ocean deoxygenation poses implications for ocean productivity, nutrient cycling, carbon cycling, and marine habitats.
Ocean warming exacerbates ocean deoxygenation and further stresses marine organisms, limiting nutrient availability by increasing ocean stratification through density and solubility effects while at the same time increasing metabolic demand. According to the IPCC 2019 Special Report on the Ocean and Cryosphere in a Changing Climate, the viability of species is being disrupted throughout the ocean food web due to changes in ocean chemistry. As the ocean warms, mixing between water layers decreases, resulting in less oxygen and nutrients being available for marine life.
Deep Sea Mining
A new issue facing the Ocean is that of deep-sea mining. The metals required in our laptops, phones and batteries can be found on the seafloor which causes great destruction to oceans.
The prospect of deep-sea mining has led to concerns from scientists and environmental groups over the impacts on fragile deep-sea ecosystems and wider impacts on the ocean's biological pump.
It is true to say that ‘BE A WISE MAN, OCEAN IS NOT A GARBAGE CAN’
Ways to protect the ocean
Here are some practical ways that you can help reduce ocean pollution:
1. Use fewer plastics.
Plastic pollution makes up a significant portion of the ocean’s debris because many ocean plastics can take thousands of years to break down properly. One way to help prevent plastic waste from making its way to the ocean is to reduce the number of plastic products you use in your own home, from plastic bags to food storage. Opt for glass, metal, or eco-friendly bamboo materials that take less time to decompose.
2. Opt for multi-use products.
Single-use plastics or paper goods like utensils, straws, paper towels, and plastic bottles are major contributors to ocean pollution. Swapping these products for multi-use items like metal cutlery or cloth napkins can reduce the amount of waste you generate with every meal. Keep your own reusable water bottle on hand rather than buy new bottles from the grocery store.
3. Avoid chemical fertilizers.
The chemical fertilizer that you use on your lawn or in your garden can eventually make its way to the ocean through rivers, rainwater, and other waterways—even if you live far from the coast. To reduce the chance of leaching chemical fertilizer and polluting the ocean, opt for natural fertilizer options like compost, bone meal, and aged manure.
4. Recycle.
Recycling is a process that converts used materials into new ones, keeping waste out of trash cans, gutters, and landfills, where they could be taken by wind or water to the ocean. Reach out to your local recycling plant or waste management operation for an approved list of recyclables.
5. Lower your energy use.
Companies worldwide burn fossil fuels to provide homes with electricity, heat, gas, and other comforts. Some of these fossil fuels (like oil) are harvested in the ocean, and burning them releases more carbon dioxide, which contributes to the acidification of our oceans. Reducing the amount of energy that you use daily helps reduce the number of fossil fuels we burn. Opt for energy-efficient appliances, turn lights off when not in use, be mindful of your car’s emissions, and keep your thermostat at a reasonable level.
6. Support an environmental advocacy group.
While you can do a lot on your own to reduce ocean pollution, there are many kinds of ocean pollution—from chemical pollutants to oil spills—that are hard to fight individually. Consider joining an environmental advocacy group to raise awareness on a local, national, and global scale.
References:
Published online: 2 March 2021 Environmental Science and Pollution Research (2021) 28:19544–19562
4)https://oceana.ca/en/blog/five-animals-impacted-plastic-pollution-and-how-you-can-help-protect-them
NEW WORDS: Nanoplastics, marine debris, microplastics.
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