MARTA goes underwater and gets to work

MARTA's expansion to the Atlantic Ocean is going exactly to plan.

Why it matters: Reef habitats are beginning to develop on decommissioned rail cars that the transit agency gave to the Georgia Department of Natural Resources and dumped off the coast of Savannah.

Zoom in: DNR divers recently made their first visit to the railcars and saw signs of corals, sponges, and other "encrusting organisms" taking hold, MARTA said in a statement.

The intrigue: "You'll notice one of the railcar roofs has collapsed, which is typical," Cameron Brinton, a DNR marine biologist.

• "[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."

Zoom out: Other items added to the ocean floor over the past 50 years include "M-60 battle tanks, barges, tugboats, New York City subway cars, and other manmade structures."

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