Reef Balls Revive a Barren Bay: How Simple Structures Are Rebuilding Placentia Bay’s Underwater World

For most of human history, the ocean floor was a place we could only imagine – unless you were a daring deep‑sea diver. Today, thanks to a handful of cameras and a lot of ingenuity, we can actually watch what’s happening down there, and not all of it looks pretty. In parts of Newfoundland and Labrador, the seabed looks more like a gray wasteland than a thriving ecosystem.

Enter the Marine Institute’s coastal lab, known as The Launch, in Holyrood. About a year ago, fisheries technologist Mark Santos and project engineer Bethany Randell gathered a crew, a few big trucks, and 285 cement “reef balls” and set them down in the murky waters of Fox Harbour, a little inlet of Placentia Bay that had been scarred by dredging. The balls aren’t just random concrete lumps – they’re designed with lots of nooks, crannies and a porous cement that lets sunlight and algae get a foothold.

“It was a desert,” Santos says, recalling the barren stretch of sand and mud. “The big dredging project stripped away the natural seed bank, so we had a clean slate – not a good thing for marine life.” The partnership with a major oil company and provincial government turned that blank slate into a laboratory for hope.

Once lowered to the bottom, the reef balls began to change. Algae started to cling to their surfaces, turning the grey concrete into a green carpet that feeds the tiny organisms floating in the water, known as marine snow. Those microscopic diners, in turn, attract bigger guests. An underwater camera, now streaming live on SmartAtlantic.ca, shows lobster claws poking out of tiny slots, small fish darting among the gaps, and even the occasional shy crab taking a look‑around.

“If you watch the footage you’ll see lobsters sticking out of these little slots, their claws just waving at you,” Santos laughs. “It’s like watching a tiny underwater city being built before your eyes.” Bethany adds that seeing the habitat take shape is why she got into ocean science in the first place – it feels like fixing a piece of the planet that’s been broken for far too long.

The reef balls are built to last. Made from a special cement mix, each ball could endure up to five centuries underwater. While the current monitoring phase is slated for nine years, the team hopes to keep the cameras rolling as long as the hardware survives, documenting how the ecosystem evolves over decades.

So far, the results are promising. Lobsters have migrated in, using the interstitial spaces for shelter and breeding. Algae continues to flourish, providing food for grazers, which in turn lure predators. It’s a chain reaction that reminds us how interconnected marine life really is.

Both Santos and Randell are already dreaming bigger. “If this works here, why not try it elsewhere?” Randell muses, eyes already on other degraded seabeds around the province. Their work shows that, with a little concrete and a lot of patience, we can coax nature back to places we thought were lost.

In the end, the reef balls are more than just plastic‑looking spheres; they’re tiny beacons of restoration, proof that a bit of human ingenuity can nudge the ocean toward recovery.