Oil Pollution

We all know that oil and water do not mix. Oil molecules are repelled by water so the water molecules attract each other and the oil molecules stick together forming two separate layers. So when oil ends up in the ocean, water molecules sink and the oil sits on top of the water.

Oil pollution is a bigger problem than you might think. Considering the size of the ocean, it is difficult to get exact numbers; but sources estimate that between 1.3 – 3.2 millions tons of oil enter the ocean every year from a variety of sources. Since oil and water do not mix, even an oil spill of less than a liter can create an oil slick of two acres (8000m2)!

Not all oil entering the ocean comes from humans. Globally as much as 40% enters the ocean naturally as oil under the sea bed can seep into the water from cracks in the searock floor. In areas of natural seeps, marine bacteria have evolved to consume much of these oil molecules. Unfortunately, these marine bacteria have only evolved in areas with natural oil seeps. When oil pollution enters the water in other areas, the ocean has little or no natural ability to cope with the contamination.

Petroleum hydrocarbons, which are found in oil, are toxic to all forms of life and can kill many organisms. Oil cannot dissolve in water and forms a thick sludge in the water which can do external damage to many species. Additionally, toxic compounds in oil can cause long-term problems in animals (and humans) such as heart damage, stunted growth, immune system effects, and even death.

The damage done by oil pollution depends upon the amount of oil and where the oil enters the ocean. In cold water, a dime-sized drop of oil could kill a seabird. More dramatically, the Deepwater Horizon spill in the Gulf of Mexico is estimated to have killed over 82,000 birds, 25,900 marine mammals, 6,000 sea turtles and tens of thousands of fish, among others.

Here are some examples of the damage marine oil pollution can cause.

Marine Ecosystems

  • The layer of oil on the surface of the water blocks the light source from all photosynthetic aquatic plants such as seagrass ecosystems.
  • Mangroves have roots which “breathe” for the trees; spilled oil coats these roots and causes the trees to suffocate.
  • The small plants that inhabit coral reefs also rely on sunlight for photosynthesis. Additionally, if the oil settles into the water column, it can coat the surface of the coral and the toxic properties can cause reproductive and developmental damage.

Marine Mammals
Since they need to come to the surface for air, marine mammals are directly affected by oil pollution at the surface.

  • In sea otters, oil strips away the insulating properties of their fur, leaving them at risk of hypothermia.
  • Whales and dolphins inhale the oil which has been shown to affect their lungs, immune function and reproduction.
  • Studies of dolphins in the Gulf of Mexico after Deepwater Horizon, show higher rates of reproductive failure, lung disease, heart issues, and stress response; even nearly 10 years later.

Other Marine Animals

  • Sea turtles mistake oil for food and can die from ingesting the toxins.
  • Not only does oil get caught in sea bird feathers and prevent them from flying; but it destroys the water repellency of the feathers, exposing them to hypothermia.
  • As oil settles into the water column, fish feel the effects. Fish have been shown to grow with deformed hearts and spines, experience fin erosion, enlarged livers, and reproductive impairments.

Oil enters the ocean from three main sources: natural oil seeps, land-based sources, and sea-based sources.

Although big oil spills in the ocean get a lot of media attention and cause an incredible amount of localized damage, they only account for about 12% of marine oil. In fact, more oil reaches the ocean each year as a result of leaking automobiles and other land-based accumulation than the oil spilled by the Exxon Valdez or the Deepwater Horizon!

Three times as much oil is carried to the sea via runoff from our roads, rivers and drainpipes as from big oil spills. Have you seen a rainbow-colored sheen on wet pavement? This is the oil that leaks from our vehicles on a regular basis. When it rains, the dripping oil that has accumulated on roads and parking lots washes down storm drains. Storm drains are not connected to any water treatment facilities so this polluted water ends up in our streams and rivers, and eventually, the ocean.

Land-based oil doesn’t only come from leaking automobiles. Animal fats and vegetable oils can have the same or similar impacts on the aquatic environment as petroleum oils when not disposed of properly.

And as for other sea-based sources? Accidental (or intentional) oil releases from tankers, offshore platforms, and drilling rigs as well as leaking commercial shipping vessels and recreational boats or illegal tank-cleaning at sea account for the rest.

Controlling and preventing land-based marine oil pollution sources should be everyone’s responsibility. There are many things all of us can do to help, including:

Spread Awareness

  • Talk about oil pollution and its impact on the ocean. Change will only come if people know what is happening and are inspired to make personal changes.
  • Educate the next generation as they are inheriting the ocean from us. The US Environmental Protection Agency has online resources to teach kids about marine oil pollution.
  • Support regulations that reduce marine oil pollution such as requiring double hulls in oil tankers which reduce the risk and severity of a spill in case of a collision or grounding.
  • Encourage your community to plant grass, trees and shrubs in bare areas. These plants will reduce and absorb runoff. Do this at home as well!

Make Personal Changes

  • Reduce the use of automobiles. Opt for alternative means of transportation: walking, biking, or riding the bus to work each day.
  • Have your car serviced regularly to reduce leakage.
  • Properly dispose of motor oil and household chemicals. Never pour chemicals on the ground or in storm drains. Used motor oil should be taken to oil recycling facilities.
  • Reduce your consumption of household and personal items made from oil and gas. Did you know that plastics are made with oil and natural gas? By reducing your use of plastics, you can also reduce your consumption of oil. Increase your knowledge of what products you use and what they are made of using the Consumer Product Information Database. Then you can opt for more environmentally friendly products.

Fortunately, if an oil spill occurs around the world, many local and international organizations are quick to help!

These organizations regularly work to spread the word about oil pollution and its effects and help to minimize the damage to the ocean.

The Ocean Foundation

Yellow Fish Campaign, United Kingdom
Groundwork, a UK group who focuses on practical community action is calling for “only rain, down the drain!” Through their yellow fish campaign, they are painting yellow fish next to street drains as a reminder not to put oil, chemicals, or litter down the drain.

Reduction in Tanker Spills, International Maritime Organization
Over the past 50 years, due to increased safety and procedures, oil spills from tankers have decreased dramatically despite the increase in oil shipping. The International Maritime Organization put together an exhibition showcasing this success.