The black crude oil hidden beneath the earth's surface is just as important to our survival as the oil we use in our kitchens. This type of oil is used to manufacture fuels and polymers, and it is transported and exported to every region of the world. However, insufficient management and maintenance almost always result in oil leaks. But how exactly do oil spills impact marine life, ecosystems, and the surrounding environment, and to what degree do they do so? We will dive deep into this today.

What is Crude Oil?

Crude oil is a form of fossil fuel that can be refined into a broad variety of other fuels and goods. It is made up of the liquid leftovers of dead plants and animals. Oil reservoirs can be discovered either below the surface of the earth or below the ocean floor. These reservoirs contain oil droplets that are trapped in the "pores" or holes in the rock. When oil corporations have successfully extracted crude oil through drilling and pumping, the next step is to transfer it to processing plants known as refineries using pipes, ships, trucks, or trains. There, the oil is refined so that it may be converted into various petroleum products. These goods include gasoline and other fuels, in addition to things that are utilized in our everyday life such as plastics, soaps, and paints.₁ Nevertheless, catastrophic environmental harm is caused whenever oil of any kind is discharged into the ocean, regardless of how it happened. The estimated 706 million gallons of waste oil that are dumped into the water each year have a detrimental impact on the environment.₂ 

So, what are the causes of oil spills? In the next section, we look into this point.

Causes of Oil Spills

The natural occurrence of oil spills in oceans can have significant negative consequences for nature. In point of fact, natural seeps of oil and natural gas are responsible for the introduction of as much as one-half of the oil that is found in the coastal environment. The erosion of sedimentary rocks at the ocean floor causes oil of this kind to seep up from the depths on a regular basis, which then pollutes the marine ecosystem. Oil seepage is typically seen in regions where oil and gas production activities are also located. Other natural factors at play include meteorological conditions and disturbances. Marine life is able to adjust to the new environment because, despite the massive spill, the soil seeps out at a very slow rate. Furthermore, the oil is more natural and has less toxicity than processed refined oil.₃,₄

However, the leaks and spills that occur as a result of anthropogenic causes, such as oil refining, handling and transport, storage, and consumption of crude oil and any of its distillation products, are responsible for the greatest amount of damage that are caused by oil spills. The majority of them are comprised of spills that were caused by accident, which can take place under a variety of conditions. For example, if the containers are not properly maintained and kept in the proper way, the oil may seep out of them. On the other hand, huge and unexpected spills are typically the result of accidents that occur during offshore drilling or ruptures that occur on large transportation boats such as tanker ships.₅,₆

Intentional oil discharges include things like tanker ship captains cleaning their tankers and washing away the residual oil directly into the ocean. This causes oil to be released into the environment. Even though this may not seem like a big deal, the fact that there are so many ships and the tankers are so massive means that the total amount of oil that is spilled could add up to a significant amount.₅,₆

Now that we know about the causes of oil spills, let’s talk about some of the major oil spills throughout the years. 

Major Oil Spills

As recently as the 1970s, oil leaks occurred at a rate of 78.8 leaks per year on average.₇ The Amoco Cadiz oil leak in 1978, when a big crude carrier carrying over 69 million gallons of light crude oil got aground on shallow rocks off the coast of Brittany, France, was one of the worst accidents of the time. The force of the collision ripped breaches in the ship's hull and its container tanks, allowing the oil to spill out. The oil spill poisoned oyster beds and killed millions of invertebrates along 321 kilometers of the French coast; among the victims were an estimated 20,000 birds.₈

The number of oil spills has dropped dramatically from an annual average of 78.8 in the 1970s to 6.2 in the 2010s as a result of improved prevention and response measures. Even though there have only been a handful such accidents in recent years, their impact has been significant.₇,₈ On April 20, 2010, a burst of natural gas blew through a cement well cap that had recently been erected to seal a well drilled by the Deepwater Horizon oil platform in the Gulf of Mexico, causing the greatest accidental spill in marine oil drilling operations. Eleven workers were killed, and seventeen were hurt, in the tragedy. In total, 206 million gallons of oil were spilled, enough to cover the 2,100 kilometers of the US Gulf Coast between Texas and Florida.₈

Threats Caused By Oil Spills

When oil leaks from broken ships, pipelines, or offshore rigs, the consequences can be devastating for the ecosystem and can endure for decades. Some of the most noticeable effects of spills on the environment include the following:

Threats to Coastal and Wetland Ecosystems: When oil spills occur, they coat everything in their path and become permanent fixtures in the ecosystems they invade. Once an oil slick from a major spill reaches a beach, it completely covers and clings to every single rock and particle of sand there. Fibrous plants and grasses absorb oil if it washes into coastal marshes, mangrove forests, or other wetlands, damaging vegetation and making the area unsuitable for wildlife habitat.₉

After a while, oil stops being buoyant and sinks to the ocean floor, where it can continue to wreak havoc on marine life and threaten delicate ecosystems, posing a threat to the survival of fish and other marine life that play a crucial role in the global food chain. National Oceanic and Atmospheric Administration (NOAA) research, for instance, discovered that 26,000 gallons of oil were still stuck in the sand along the Alaska shoreline despite extensive clean-up operations following the 1989 Exxon Valdez oil spill. Scientists working on the study found that residual oil was depleting at a rate of less than four percent per year.₁₀

Threats to birds: Birds harmed by oil are an ubiquitous image of the destruction oil spills cause to ecosystems. However, sea birds that rely on swimming and diving for their food are much more likely to become coated in oil after a spill than shore birds that might be able to flee by moving elsewhere if they detect danger in time. Likewise, oil spills can destroy nesting areas, which can have devastating long-term consequences for entire species.₁₁ For birds, even a trace amount of oil can be fatal. Coating feathers with oil not only prevents birds from flying but also eliminates their natural protection against the elements and thermal regulation, leaving them susceptible to hypothermia or thermal overload. Preening their feathers feverishly to restore their natural defenses, birds often swallow the oil, which can cause significant harm to their internal organs and ultimately kill them.₁₂

Threats to marine mammals: Whales, dolphins, seals, and sea otters are just some of the marine creatures that commonly fall victim to oil spills. Whales and dolphins may have trouble breathing and communicating if oil accumulates in their blowholes. Otters and seals stay at risk of freezing to death in cold weather if their fur becomes slick with oil. An oil spill can damage marine creatures' food sources even if the animals themselves are spared direct harm. Marine animals may suffer from oil poisoning or other issues if they consume fish or other food that has been contaminated by an oil spill.₁₃

Threats to fish: When many fish eggs or larvae are exposed to oil, the results can be catastrophic for fish and other marine species, which might include the destruction of an entire breeding cycle. In a similar vein, the Exxon Valdez leak was responsible for the loss of billions of salmon and herring eggs. It took fisheries over three decades to recover from the Exxon Valdez.₁₃,₁₄,₁₅

Threat to habitat and breeding: One of the most far-reaching repercussions of oil spills on the ecosystem is the permanent destruction of species and their habitats, nesting grounds, and breeding areas. Species like sea turtles, who spend the vast majority of their life in water, must still nest on land. Oil in the water or on the beach where sea turtles lay their eggs can be harmful to the turtles, the eggs may not hatch properly if they come into contact with oil, and newly hatched turtles may be oiled as they make their way to the ocean through an oily beach.₁₆,₁₇

As long as ships carry the vast majority of the world's petroleum products and as long as an exploration of oil from maritime resources continues to increase, oil spills will continue to be a pressing problem and a source of pollution. This will be the case as long as these two factors remain constant. However, oil spills almost always take place unintentionally, and as a result, it is becoming increasingly vital to deploy a wide variety of cleanup solutions in order to combat the threat that these spills could represent to marine ecology.

Works Cited

1. https://www.energy.gov/sites/prod/files/2013/04/f0/HS_Oil_Studyguide_draft2.pdf

2. https://www.futurebridge.com/industry/perspectives-energy/oil-spill-prevention-solutions-and-challenges/

3. https://www.whoi.edu/know-your-ocean/ocean-topics/how-the-ocean-works/seafloor-below/natural-oil-seeps/

4. https://response.restoration.noaa.gov/oil-and-chemical-spills/oil-spills/resources/what-are-natural-oil-seeps.html#:~:text=Crude%20oil%20and%20natural%20gas,bring%20water%20to%20the%20surface

5. https://response.restoration.noaa.gov/training-and-education/education-students-and-teachers/how-do-spills-happen.html

6. https://earth.org/oil-pollution-and-spills-who-is-responsible/

7. https://www.researchgate.net/figure/Number-of-spills-based-on-tons-of-oil-from-1970-to-2019-ITOPF-2019_fig1_350831759

8. https://www.britannica.com/list/9-of-the-biggest-oil-spills-in-history

9. https://www.noaa.gov/education/resource-collections/ocean-coasts/oil-spills

10. https://pubs.acs.org/doi/10.1021/es0620033

11. https://www.epa.gov/sites/default/files/2018-01/documents/ospguide99.pdf

12. https://www.sciencedirect.com/science/article/abs/pii/S0048969720363646?via%3Dihub

13. https://oceanservice.noaa.gov/facts/oilimpacts.html#:~:text=Oil%20destroys%20the%20insulating%20ability,mammals%20will%20die%20from%20hypothermia

14. https://www.sciencedirect.com/science/article/abs/pii/S0025326X15000818?via%3Dihub

15. https://darrp.noaa.gov/oil-spills/exxon-valdez#:~:text=The%20spill%20affected%20more%20than,2%2C800%20sea%20otters

16. https://www.gulfspillrestoration.noaa.gov/sites/default/files/wp-content/uploads/Overview_10-08-15_for-posting.pdf

17. https://response.restoration.noaa.gov/oil-and-chemical-spills/oil-spills/resources/oil-and-sea-turtles.html