Researchers have teamed up to find the largest area of seagrasses on Earth with tiger Sharks.
A massive survey of the Bahamas Banks — a cluster of underwater plateaus surrounding the Bahama archipelago — reveals 92,000 km of seagrassesOliver Shipley, a marine biologist, and his colleagues report on November 1, 2012. Nature Communications.It is about half the area of Florida.
The finding expands the estimated global area covered by seagrasses by 41 percent — a potential boon for Earth’s climate, says Shipley, of the Herndon, Va.–based ocean conservation nonprofit Beneath The Waves.
Seagrasses can trap carbon for millennia at high rates 35 times fasterUnlike tropical rainforests. The team estimates that the newly mapped sea-grass prairie may contain 630 million metric tonnes of carbon. This is about 25% of the carbon stored by seagrasses globally.
Shipley said mapping that much seagrass was an enormous task. He and his team used satellite data to guide them, so they swam in the clear blue waters 2542 times to get a close look at the meadows. To aid their efforts, the team also recruited eight Tiger Sharks. Similar to Lions that stalkThe African savanna is home to zebras that can walk through tall grasses. The sharksPatrol fields of wavy SeagrassesTo graze animals for food (SN: 1/29/18; SN: 5/21/19, SN: 2/16/17).
“We wouldn’t have been able to map anywhere near the extent that we mapped without the help of tiger sharks,” Shipley says.
The team captured the sharks with drumlines and hauled each one onto a boat, mounting a camera and tracking device onto the animal’s back before releasing it. In less than 10 minutes, the sharks were back in the water. The team operated like “a NASCAR pit crew,” Shipley says.
Researchers previously suggested that seagrass-grazing could be tracked. Manatees and sea turtlesIt is important to find suitable pastures. But tiger sharks were a smart choice because they roam farther and deeper, says Marjolijn Christianen, a marine ecologist at Wageningen University & Research in the Netherlands who was not involved in the new work. “That’s an advantage.”
Shipley and colleagues plan to collaborate with other animals — including ocean sunfish — to uncover more submarine meadows (SN: 5/1/15). “With this [approach], the world’s our oyster,” he says.
