Disappearing Seagrass Protects Against Pathogens, Even Climate Change, Scientists Find
Every continent save Antarctica is ringed by vast stretches of seagrass, underwater prairies that together cover an area roughly equal to California.
Seagrass meadows, among the most endangered ecosystems on Earth, play an outsize role in the health of the oceans. They shelter important fish species, filter pollutants from seawater, and lock up huge amounts of atmosphere-warming carbon.
The plants also fight disease, it turns out. A team of scientists reported on Thursday that seagrasses can purge pathogens from the ocean that threaten humans and coral reefs alike. (The first hint came when the scientists were struck with dysentery after diving to coral reefs without neighboring seagrass.)
But the meadows are vanishing at a rate of a football field every 30 minutes. Joleah B. Lamb, a postdoctoral researcher at Cornell University and the lead author of the new study, said she hoped it would help draw attention to their plight.
“We call seagrass the ugly stepchild of marine organisms,” said Dr. Lamb. “They don’t get a lot of respect, compared to corals and mangroves.”
Seagrass first evolved tens of millions years ago, when some flowering plants moved from land into the ocean. They still grow flowers, pollen and seeds, but they now do so underwater, with a powerful form of photosynthesis that allows them to thrive in dim light at depths of up to 190 feet.
The sediment in which they grow is loaded with deadly hydrogen sulfide. They detoxify by pumping some of the oxygen they release during photosynthesis into their roots.