effects of plastic pollution in the ocean

4 Top Known Effects of Plastic Pollution in the Ocean

In this article, we will discuss the effects of plastic pollution in the ocean.

More than 90% of manufactured plastic ends up in our oceans daily, contributing to ocean pollution.

Research shows that about 10 million tonnes of plastic products are disposed of into the oceans yearly. 

One of the significant causes of plastic pollution in the ocean is the increased production of plastic and plastic products for the ever-growing population. Humans use plastic a lot in our day-to-day activities, and after use, we discard it.

The average time most people keep plastics is about 15 minutes, after which most people dispose of the plastics. The implication is an increase in the amount of plastics in our oceans.

Ocean plastic pollution sources include extreme weather conditions, plastic transported from rivers and streams, wastewater discharges and stormwater into ocean bodies, littering along shorelines, and improper waste disposal activities that predispose our oceans to plastic pollution.

Other sources include fishing vessels, agricultural waste, runoffs, barges, landfills, and boaters. 

These activities lead to plastic pollution in our oceans. Studies state that by 2050, the amount of plastics in the ocean will increase the number of fish in the sea.

The rise in the number of plastics in our ocean occurs because it takes hundreds of years for plastic to disintegrate, and plastics do not fully decompose; they split into microplastics and nanoplastics. 

Microplastics and nanoplastics are so minute that retrieving them from the ocean is difficult. Also, due to the size of microplastics and nanoplastics, it is easy for filter feeders, special marine animals, and marine species to confuse these microplastics as food. 

4 Top Effects of Plastic Pollution in the Ocean

  • Death
  • Accumulation of chemical pollutants
  • Absorption of contaminants 
  • Production of chemical additives


One of the effects of plastic pollution in our oceans is the death of marine species. About 10 million tons of plastic reach our oceans yearly, leading to the death of over 100,000 marine species.

Fishes, whales, turtles, seabirds, and molluscs are commonly affected marine species. 

  1. Fishes 

Plastics disintegrate into microplastics and nanoplastics, which fish consume or ingest. These microplastics and nanoplastics lodge in the gills, tissues, organs, respiratory, circulatory, and digestive systems, preventing the body’s normal physiology.

One common cause of fish ingesting plastics occurs because fishes often mistake plastics for feed. 

  1. Molluscs 

Molluscs are marine species that are filter feeders. They are greatly affected by ingesting microplastics and plastics. Microplastics jeopardise the well-being of molluscs such as mussels and oysters, leading to their death. 

Recent studies from BBC show that mussels sourced from UK waters contain 100% microplastics. The effect of this is the death of marine species caused by the build-up and accumulation of microplastics in the respiratory, circulatory, and digestive systems, which disrupts breathing, blood circulation, and digestion of food. When digestion and respiration cannot occur, it leads to starvation, asphyxiation, and death.

  1. Whales 

Whales are the most susceptible to plastic entanglements. Other marine animals susceptible to entanglements are dolphins, porpoises, crabs, and more. These entanglements occur from ingesting fishing nets, fishing ropes, or plastic pots dumped into our oceans. 

In 2019, a whale was washed ashore with approximately 40 kilograms of plastics in its stomach, most of which were plastic bags and fishing gear.  

  1. Sea Turtles 

Sea turtles have a small digestive system and stomach that can only accept small food portions at once. The ingestion of plastic can lead to indigestion and starvation. Plastics are not digestible; therefore, when ingested, they lodge in the stomach, mimicking a full stomach and making it feel bloated, leading to starvation, which can lead to death. 

These plastics can also lodge in other body organs and tissues and prevent normal physiology from taking place. All these happen because sea turtles constantly mistake plastics for food, and this is a common assumption, particularly in sea turtles, as most plastics are similar to jelly, which is a typical delicacy for them.

  1. Sea Birds 

Sea beds are quite similar to sea turtles and, therefore, suffer the same effects of plastic pollution in the ocean. Plastic and plastic debris are indigestible and are responsible for the death of more than one million seabirds yearly. Death often occurs as most seabirds are surface feeders; therefore, they often mistake plastics and plastic debris found on ocean surfaces for food.

Although some sea birds can regurgitate pieces of plastic, most cannot.

Another devastating effect of plastic pollution on seabirds is that not only are older seabirds affected, but young seabirds are affected the most due to their small size and less developed system. 

Accumulation of Chemical Pollutants 

As plastic spreads throughout the ocean, it splits into smaller pieces, and some plastics sink to the bottom of the sea while the lightweight plastics stay afloat. 

As plastics split, they disintegrate they release certain chemical pollutants. Most of these chemical pollutants have been banned in most countries but still find a way into our oceans legally or illegally.

Absorption of Contaminants

A devastating effect of plastic pollution in the ocean is the absorption of contaminants by plastics, which finally end up in the mouths of marine species. 

There are five standard plastic used worldwide, and they are:

  • High-density polyethylene (HDPE)

  • Low-density polyethylene (LDPE)

  • Polyethylene phthalate (PET) 

  • Polyvinyl chloride (PVC)

  • Polypropylene (PP)

All these plastics absorb contaminants, but High-density polyethylene (HDPE), Low-density polyethylene (LDPE), and Polypropylene (PP) absorb a more significant percentage of contaminants in comparison with others. 

Plastics have continued to pick up contaminants for years. Common examples of contaminants in plastics in an aquatic environment include zinc, aluminium, mercury, cadmium, bisphenol A (BPA), phthalates, polycyclic aromatic hydrocarbon (PAH), organochlorine pesticides (OCPs), alkylphenols and polybrominated diphenyl ethers (PBDEs). 

The implication is that marine species ingest plastic with high amounts of contaminants that have serious health challenges; thus, it is hazardous to their health and well-being. 

Other implications of ingesting plastics are the associated chemicals, liver failure, compromised immune system, and death due to poor nutrition, starvation, and dehydration. However, additional research is needed to ascertain the extent to which plastic transfers contaminants to marine species and the effects of plastic ingestion.

Production of Chemical Additives 

Plastic products contain compounds and chemical additives. These additives are materials used in the manufacture of plastics.

Common examples of chemical additives are flame retardants, used to make plastics less flammable, colorants, UV stabilizers, and bisphenol A, which reinforcers to make plastics soft and flexible.

These chemical additives disintegrate from plastics when plastics have been in water bodies for a very long period, and the chemical components leach into our oceans, posing a severe chemical threat to aquatic life.

An example is bisphenol A, an endocrine disruptor that affects both the reproductive and development of marine species. In sensitive species such as crustaceans and molluscs, it causes disruptions in spermatogenesis.


The effects of plastic pollution in our ocean are devastating as plastic pollution has led to the deaths of millions of fish yearly while displacing others from their natural habitat and some into extinction.

Preventing plastic pollution is the best way to save our oceans and marine species. This is done by regulatory bodies enforcing strict rules that prevent individuals or organizations from disposing of plastics in our oceans.

 Other means of preventing plastic pollution are regular oceanic cleaning and thorough inspection of water wastes disposed into oceans.

These are some of the few ways we can help protect our oceans. Preventing plastic pollution would go a long way in saving marine species and human health in the long run.

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