Marine “meadows” of light green plants on the ocean floor are home to all kinds of life: turtles, fish, squid, seahorses, anemones and crabs.

In the vast expanses of the sea world, we do not yet know how many such meadows stretch – not only around distant atolls, but even along the coasts of some of the most well-mapped countries on Earth.

Seaweed extends for hundreds and even thousands of kilometers, and in areas with clear water that allows sunlight to penetrate, they can grow much deeper than a person can dive with special equipment. So when Austin Gallagher, a marine scientist, wanted to find out with his team just how vast these grasslands are in the Bahamas, he asked for help from some of the best divers in the world: tiger sharks.

By attaching cameras to these deep-diving marine predators, the team found, to their surprise, that the Bahamas had more kelp meadows than anywhere else on Earth.