Ocean Pollution

Ocean pollution is a significant environmental issue that poses a serious threat to the health and well-being of our planet.

What is ocean pollution?

Ocean pollution — also called marine pollution — is a mixture of both chemical contamination and trash. The act of ocean pollution occurs when chemicals and trash are either washed, blown or intentionally dumped into the ocean. 

What causes ocean pollution?

There are many causes of ocean pollution, but most (80%) of the pollution in our oceans originates on land and is caused by humans. Here are some of the major causes of marine pollution:

1. Nonpoint source pollution (runoff)

Nonpoint source pollution is the accumulation of pollution from small sources that can’t be exactly pinpointed. Examples include the pollution created by individual cars, boats, farms and construction sites.

Nonpoint source pollution typically becomes ocean pollution via 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. But wind can transfer dirt and other debris from nonpoint sources and deposit these pollutants on the ocean’s surface. 

2. Intentional discharge

Manufacturing plants in many areas of the world release toxic waste into the ocean, including mercury. While it has been banned in the USA, sewage also contributes to ocean pollution. Meanwhile, plastic waste poses a particularly tough challenge; according to the Ocean Conservancy, eight million metric tons of plastic go into our oceans every year.

3. 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. You can find a history of oil spills on the NOAA site, but the largest one in recent history was, by far, the 2010 Deepwater Horizon well blowout in the Gulf of Mexico, which spilled roughly 134 million gallons of oil into the ocean.  

4. Littering

Atmospheric pollution — a type of ocean pollution where objects are carried by the wind to the ocean — is often caused by littering. It includes single-use plastics (such as plastic bags) and styrofoam containers which can take hundreds of years to biodegrade. It is estimated that roughly 1 trillion plastic bags are used worldwide per year. 

5. Ocean mining

Deep-sea ocean mining causes ocean pollution and ecosystem 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.

Why is ocean pollution a problem?

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:

1. Harmful to marine life

Sea animals are frequent 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 and 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.

2. 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 oxygen 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 very little marine life can survive.

3. 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.

On an individual level, there are a few things we can do about water pollution to avoid damaging marine ecosystems:

• Refuse plastic straws at restaurants and bar
• Ask for no plastic silverware when ordering takeout
• Carry a reusable water bottle
• Recycle at home and at the workplace
• Don’t litter – take rubbish home with you
• Use eco-friendly products