A pair of old railcars from Atlanta were left off the east coast of the US last year in a fascinating experiment. After a few months of settling, researchers have witnessed how the sunken carriages are starting to develop into complex reef habitats that host a variety of marine wildlife.

After being cleared of hazardous materials and inspected by the US Coast Guard, the decommissioned railcars were transported by barge to Artificial Reef L, a well-established reef located about 23 nautical miles from Ossabaw Island off the coast of the US state of Georgia.

They were left on the seabed in December 2023 at a depth of 17 to 20 meters (55 to 65 feet) and nature was let to run its course. 

The wrecks were recently investigated by a crew of divers from the Georgia Department of Natural Resources (DNR) who documented a “good amount” of soft coral starting to grow on the railcars, plus at least nine species of game fish inhabiting the surrounding site.

“The artificial reef is looking great, and we are encouraged by the amount of coral growth and marine wildlife activity,” Cameron Brinton, a marine biologist with DNR’s Coastal Resources Division, said in a statement.

“You’ll notice one of the railcar roofs has collapsed, which is typical, and we’ll see more changes to the railcars over time as they become part of the essential marine habitat for sea creatures, including popular sport fish and endangered sea turtles,” explained Brinton.

This technique of abandoning human-made objects on the seafloor in an attempt to encourage wildlife has been tried several times. Past trials have involved the use of sunken ships, New York City subway cars, and even M-60 battle tanks provided by the US Army.

The idea is that the robust objects act as a surface for algae and invertebrates, such as shellfish and corals, to attach to. This builds up a body of plant life and reefs, providing a perfect environment for fish and other marine life to thrive within.

However, the science isn’t settled yet and artificial reefs remain controversial. Critics worry that plonking artificial structures in the sea can meddle with the natural marine processes, introduce pollutants, and have unforeseen knock-on effects on the ecosystem.

Some poorly planned projects have gone very wrong in the past. In the early 1970s, around two million car tires were tipped into the ocean near Fort Lauderdale in Florida, hoping to attract corals and fish. It didn’t go well.

Rest assured, when it comes to artificial reefs, environmental catastrophes are the exception, rather than the rule. As this latest project shows, they can deliver positive results for sealife and offer a creative way to recycle the urban detritus of the modern world.