December 01, 2020

Ocean Pollution: Causes, Effects and Prevention

Oceans, which account for 70 percent of the surface of our planet, play a pivotal role in the health of our planet and those who inhabit it. Unfortunately, our oceans are polluted. According to the National Oceanic and Atmospheric Administration, billions of pounds of trash and other pollutants enter our oceans every year.

The monumental impacts of this are far-reaching. In this post, we’re taking a closer look at the various causes of ocean pollution, its effects and the steps we can take to combat it. 

Causes of Ocean Pollution

There are many causes of ocean pollution. Of all the facts, there is one constant: most pollution in our oceans begins on land and is caused by humans. Here are some of the major causes of marine pollution:

Nonpoint source pollution (Runoff)

Nonpoint source pollution comes from a variety of different locations and sources. The result of this is runoff, which occurs when rain or snow moves pollutants from the ground into the ocean. For instance, after a heavy rainstorm, water flows off roads into the ocean, taking oil left on streets from cars with it.

Intentional discharge

Manufacturing plants in some areas of the world release toxic waste into the ocean, including mercury. While it’s intentionally being released into the sea, sewage also contributes to ocean pollution, as well as plastic products. According to Ocean Conservancy, eight million metric tons of plastic goes into our oceans every year.

Oil spills

Ships are major contributors to ocean pollution, especially when crude oil spills occur. Crude oil lasts for years in the ocean and is difficult to clean up.


Atmospheric pollution, which refers to objects carried by the wind to the ocean, is a big problem. Items such as plastic bags and styrofoam containers become suspended in the water and don’t decompose.

Ocean mining

Deep-sea ocean mining causes pollution and disruption at the lowest levels of the ocean. Drilling for substances such as cobalt, zinc, silver, gold and copper creates harmful sulfide deposits deep in the ocean.

Effects of Ocean Pollution

Ocean pollution has many consequences that directly and indirectly affect marine life, as well as humans. Here are some of the most common effects of ocean pollution:

Harmful to marine animals

Sea animals are common victims of ocean pollution. Oil spills, for instance, will ensnare and suffocate marine animals by permeating their gills. When the oil gets into seabird feathers, they may not be able to fly or feed their young. Animals that aren’t killed by crude oil may suffer from cancer, behavioral changes and become unable to reproduce.

Marine animals also mistake small plastic debris for food or become entangled in or strangled by plastic bags and discarded fishing nets. Animals most vulnerable to harm from plastic debris in the ocean include dolphins, fish, sharks, turtles, seabirds and crabs.

Depletion of oxygen in seawater

As excess debris in the ocean slowly degrades over many years it uses oxygen to do so, resulting in less 02 in the ocean. Low levels of oxygen in the ocean lead to the death of ocean animals such as penguins, dolphins, whales and sharks.

Excess nitrogen and phosphorus in seawater also cause oxygen depletion. When a great deal of oxygen depletion occurs in an area of the ocean, it can become a dead zone where no marine life can survive.

A threat to human health

Pollutants in the ocean make their way back to humans. Small organisms ingest toxins and are eaten by larger predators, many of which are seafood that we eventually eat. When the toxins in contaminated animals get deposited in human tissue, it can lead to long-term health conditions, cancer and birth defects.

Ocean Pollution Solutions

Given the long-term, disastrous effects of ocean pollution, anything we can do to avoid contaminating our seas is a good idea. Here are some ocean pollution solutions that can make a big difference.

Reduce chemical fertilizer use

Excess chemical fertilizer eventually makes its way into the oceans. Choose organic fertilizers, which tend to be lower in nutrients, and use them at half strength or half as often as suggested.

Opt for reusable bottles and utensils

Throw-away plastic bottles and utensils, including straws, are massive ocean polluters. Rather than contributing to the threat to marine life, opt for reusable bottles and utensils.

Hold a cleanup

Organize a social distancing cleanup at the beach or a nearby park. The more trash you pick up and properly dispose of, the less waste goes into our oceans.

Properly dispose of plastics and trash

One of the simplest ways to reduce ocean pollution is to properly dispose of plastics and other recyclable materials, so they don’t end up in the ocean. In outdoor spaces, such as beaches and parks, dispose of trash in a secure receptacle or take it home with you.

To help encourage proper disposal, we recommend downloading our Waste Wizard App which allows you to input common waste items and see how to properly dispose of them. With a few small changes to our daily routines, we can all do our part to help reduce the amount of pollution going into our oceans. 

Find out what also contributes to land pollution.