An unlikely team of researchers and a tiger shark who understands this have discovered the world’s largest seagrass ecosystem. It’s tucked away just off the coast of the Bahamas.their result is Nature Communications.
Joseph Polidoro: this is Scientific American science fastI am Joseph Polidoro.
As ecosystems progress, seagrass is right up there with rainforests and coral reefs.
Austin Gallagher: in fact, one of the most important hubs or magnets for biodiversity.
Polydoros: Austin Gallagher is a marine biologist and CEO of Beneath the Waves, a non-profit ocean conservation organization.
Seagrass is the nursery for one-fifth of the world’s largest fishery and a haven for thousands of species. They protect other habitats and coastlines. And store vast amounts of carbon that would otherwise be released into the atmosphere.
Gallagher: It’s like this incredible unsung hero of marine conservation.
Polydoros: But half of the world’s seagrass remains undiscovered. We protect these important ecosystems with surveys as accurate as early Renaissance maps of the New World.
This is because, unlike mangroves and warm water reefs, seagrass meadows are not always detected by satellite or airborne observations. Cloud cover and glare from the seafloor also help keep the Bahamian seagrass hidden.
Carlos Duarte: There are a lot of false negatives and false positives.
Polydoros: Carlos Duarte is a marine ecologist at King Abdullah University of Science and Technology, Saudi Arabia.
duarte: If I had tried to do it myself, I probably would never have tried.
Polydoros: For decades, Carlos believed that the Bahamas Banks could host giant seagrass habitats. But he couldn’t prove it.
duarte: Remote sensing does not provide a reliable record. And it turned out to be impossible to justify the Bank of the Bahamas because of its sheer size.
Polydorus: By the way, ground truth is the establishment of the truth in the field by direct observation. For seagrass, this is usually done by divers or researchers on boats.
Gallagher: I really believe that this discovery might not have happened if we hadn’t come together like we do.
Polydorus: Later, by chance, Carlos met Austin and saw footage from Austin’s shark-mounted camera.
Gallagher: We saw these vast underwater seagrass meadows.
Polydorus: Carlos has found his ground truther.
Gallagher: Tiger Shark was a complete game changer for this whole process. Tiger sharks love seagrass habitats. The tiger shark is this great ally.
Polydorus: But how do you collaborate with a big carnivorous shark?
Gallagher: These tiger sharks have teeth that can do serious damage. And that doesn’t demonize them. it’s just a fact.
Polydoros: For the study, Gallagher’s team captured eight tiger sharks and attached them with satellite tags. The researchers also attached cameras to seven more sharks. at first …
Gallagher: The waves are crashing, it’s just too busy, everyone’s screaming. We’re trying to hoist this animal up and restrain it, wrap a rope around its tail, and secure it to the side of the boat.
Polydorus: Once you secure the shark…
Gallagher: Well, it’s actually amazing. It’s kind of calm and very peaceful.
Polydorus: In an average of 12 minutes for each shark, the team took measurements, collected blood samples, and set up the recording device. The shark was then released to roam Banks’ seagrass meadows.
Tiger sharks were far better observers than humans.
duarte: They run 24/7 and cover about 70 kilometers per day.
Polydoros: And the cost is 1/5th that of humans or drones.
By combining shark footage and location data with surveys of thousands of boats and divers, the team was able to correctly interpret the satellite imagery…
Gallagher: Ultimately, it reveals the world’s largest seagrass meadow, covering up to 93,000 square kilometers.
Polydoros: This is about the size of Portugal and about 40 times the original estimate. The discovery increased known seagrasses globally by a third of his.
According to Carlos, the world’s remaining undiscovered seagrass meadows are getting smaller. To map them, Carlos uses sea turtles, another charismatic inhabitant of the seagrass ecosystem.
duarte: We’re doing it right now in the Red Sea and we’re getting very reliable mapping.
Polydoros: Carlos and his colleagues will soon be exploring the Maldives and other archipelagoes and island nations in Southeast Asia.
Seagrass mapping is not only useful for seagrass conservation. It can also benefit people who live nearby.
duarte: If we look at the carbon assets of seagrass meadows and the emission reductions that can be achieved through their conservation, and assign them to 300,000 people …
Polydoros: He mentions the population of the Bahamas – now over 350,000 …
duarte: Basically every Bahamian has a million dollar carbon credit.
Polydoros: The team’s work also sheds a new and more flattering light on the sharks.
Gallagher: These tiger sharks led us to a meadow of seagrass. And we have found this to be of great benefit to the Bahamian people moving forward.
It really shows that if we protect sharks like the Bahamas did, we have the potential to protect people.
No small achievement for 15 tiger sharks and their friends.
Polydorus: for Scientific Americanof science, quick, My name is Joseph Polidoro.
science fast Produced by Jeffrey Dervicio, Turika Bose and Kelso Harper.follow Scientific American For updated and detailed science news.
