Teeming With Life

Oil rigs usually make headlines for hurting sea life, not saving it. These large steel structures drill for oil beneath the seafloor—disrupting the fish and other marine life in the area. But scientists are finding that unused oil rigs are also thriving habitats for aquatic animals. Stationary species like coral, mollusks, and sponges latch onto the beams. Thousands of fish weave in and out of the structures looking for food and shelter. The platform above the surface may be abandoned, but there is a colorful marine metropolis under the water.

When an oil reservoir is tapped out, the rigs are no longer needed. Normally, decommissioned rigs are removed—a costly and environmentally disruptive process. But a group called Blue Latitudes is spearheading the Rigs-to-Reefs program to preserve the unused rigs for marine life. 

Sea creatures can’t resist the living space the rigs have to offer. “As soon as [a rig is] put into place, they start colonizing,” says Emily Callahan, co-founder of Blue Latitudes. So far the group has transformed almost 500 oil rigs in the Gulf of Mexico into artificial reefs.

Artificial reefs like these are becoming more important now that naturally occurring reefs are threatened by overfishing, pollution, and climate change. Because of their position offshore, oil rigs are also protected from construction and coastal pollution that can affect natural reefs closer to shore.

Amber Jackson, Blue Latitudes’ other co-founder, says oil rigs are ideal artificial reefs because they’re designed to be submerged in the ocean for many years. Other artificial reefs made from retired subway cars or sunken ships have metal that decays in the salty seawater.

Engineers hope to take the lessons from studying the habitats below oil rigs and apply them to designing future offshore structures like floating wind turbines. The result: Humans get energy while sea life gets a home, the perfect ocean-based win-win.

Use the information above to find how much area of the seafloor different artificial reefs cover.

A decommissioned oil rig in the Gulf of Mexico has a roughly rectangular in shape. It’s 308 feet wide and 374 feet long. What area does the rig take up on the ocean floor? 

If the rig in No. 1 were tipped over to lie along the ocean floor, it would be trapezoidal in shape with a top base of 308 feet, a bottom base of 370 feet, and a height of 433 feet. What area would it take up now? 

There were 304 active oil rigs in the Gulf of Mexico in 2015. If each oil rig had a square base with a side length of 278 feet, what was the total seafloor area covered by all the rigs in the Gulf of Mexico?

Concrete is also used for custom-shaped artificial reefs. One type of artificial concrete reef is a half-sphere that rests with its full diameter on the seafloor. Its diameter is 3 feet. What is the area it takes up on the ocean floor? 

New York City has submerged retired subway cars to serve as artificial reefs—even though the cars were not initially designed to go in water. One side of a subway car is 51.33 feet long and 11.89 feet high. What’s the area of that side of the subway car?