On a sunny July afternoon along the shores of Hong Kong’s Lamma Island, the receding tide reveals an unassuming patch of greenery that scientists describe as the “ultimate underwater superheroes” for boosting marine biodiversity.
Seagrass – an easily overlooked marine plant – can lock away climate-warming carbon 35 times faster than tropical rainforests.
But levels of this vital vegetation in local waters have plummeted by 60 per cent over the past two decades, while sightings of local green turtles, which feed on it, have also dropped significantly.
According to the latest government figures, local live sightings of green turtles dropped from 17 in 2019 to seven in 2025. Strandings have also declined, falling from 16 in 2018 to two this year.
In a bid to turn the situation around, researchers are working with villagers to plant more seagrass.
“Seagrasses are the ultimate underwater superheroes,” said Juan Diego Gaitan-Espitia, an associate professor of biological sciences at the University of Hong Kong (HKU).
“Without these quiet champions, both the global fight against climate disruption and the very livelihoods of coastal populations will be threatened.”
