Deepwater Horizon Oil Spill Kills Millions

The Deepwater Horizon spill is known as the worst oil spill in U.S. history. To fully understand this event, it is important to know the science behind it.

On April 20th, 2010, the Deepwater Horizon oil rig exploded and sunk in the Gulf of Mexico, killing 11 and injuring 17 people. The BP pipe leaked oil and gas on the ocean floor just 42 miles away from the Louisiana coast. The well was detected more than 5,000 feet under the water’s surface. When the well was finally capped 87 days later on July 15, approximately 3.19 million barrels (more than 130 million gallons) of oil had leaked into the Gulf. Right after the explosion, several government agencies attempted to control the oil from spreading to beaches and other coastal ecosystems by using floating barriers to contain surface oil and chemical oil dispersants to break the oil into little pieces underwater.

The little pieces of oil in the water mixed with the seawater. Some pieces landed on the seafloor and damaged deep sea corals and other ecosystems that are hidden beneath the surface. When oil spills in water, it tends to float and spread out, forming slicks, which often look like a rainbow and can be seen in parking lots after a rainstorm. To clean it up, workers surround the slick with floating barriers called “booms”. Then they use multiple tools to remove the trapped oil. Often they’ll drive “skimmers”, boats that skim spilled oil from the water’s surface, through the slick. “Sorbents” are used to mop up traces of oil left behind by skimmers. They either absorb oil like a sponge, or adsorb oil, in which oil sticks to its surface.

Oil slicks can harm coastal ecosystems and animals, so cleanup workers use dispersants to stop them from forming or going to a protected area like a harbor or marsh. This can be a beneficial for animals found on the surface and coast, like seabirds and animals living in the Gulf’s mangroves, because the oil is moved out of their homes. However, the dispersants could infiltrate the food chain and ruin wildlife. For the Deepwater Horizon spill, more than 1.4 million gallons of chemical dispersants were used.

There were instant impacts to the Gulf’s animals: pelicans covered in black oil, fish surrounded by sludges, and oil smothered turtles found on the beaches. Rare Kemp’s ridley sea turtle nests (an endangered sea turtle species) have decreased over the years since the spill. Seabirds exposed to unrefined oil, even a tiny amount on their feathers, can affect their ability to fly, swim and dive to find food. The losses may have numbered in the hundred thousands. Even though the oil was eventually cleared out of human sight and moved somewhere in the deep ocean, that does not mean it’s gone, and there’s a possibility life in the deep ocean was exposed to oil and dispersants. Broken down pieces of oil were small enough to be eaten by rotifers, tiny microscopic animals. Fish eat the rotifers, and in result, oil entered their systems, possibly hurting them.

Invertebrates in the Gulf were also extremely affected by the spill. Some wildlife showed signs of deformations, such as fish with lesions and eyeless shrimp. Oil can cause heart defects in the developing larvae of bluefin tuna and other fish. Deep-sea corals grow very slowly and live for centuries, but corals near the explosion showed signs of tissue damage and were covered in oil. Lab studies showed that coral larvae exposed to oil and dispersants had much lower survival rates.

Over 1000 miles (1609 km) of shoreline on the Gulf of Mexico was hit from the Deepwater Horizon spill. It took 3 years to clean up all the oil from the oil rig. The spill affected both animals and humans by hurting the environment. This was a huge change for the ecosystems that were near the explosion in the Gulf of Mexico.