Chile's vital underwater forests face threats from mining, warming seas

In the cold seas off Chile's arid northern coast an underwater forest teems with life. Towers of red and green seaweed float upwards from the sea floor, providing food for wildlife, income for locals - and oxygen and carbon capture for the planet.

For scientists, these forests hold even more potential as sustainable protein, food and other materials, though they are threatened by warming oceans and human pollution.

"They form a belt along coastal edges, which is essentially a belt of protection and biodiversity for life," said Alejandra Gonzalez, a marine biologist from the University of Chile who specializes in marine ecosystem conservation.

She explained that seaweed produces oxygen and captures carbon dioxide, creating important carbon stores under the waves. "The future of the planet is seaweed," she said.

But these forests globally are under rising pressure. One example: kelp forests are declining at an annual rate twice that of coral reefs and over four times that of rainforests, a British Natural History Museum-backed report said in May.

"Before, these areas were very rich in seaweed, seafood, fish, things that most people in this town live off of, from seaweed harvesting," said Maria Jose Espinoza, leader of the local Changa indigenous community.

The Changa have lived off harvesting seaweeds for generations, but are worried as they've seen the forests shrink.

Espinoza blamed tailings waste from mining in the nearby copper and lithium-rich Atacama Desert region for harming coastal environments, as well as desalination plants being developed by miners he worried would hurt marine life.

Chile is the world's top copper producer and second largest lithium producer, with most mining activity in the north.

Diver Roberto Carlos Chango, out with his son to collect shellfish, agreed on the importance of the seaweed forests.

"Seaweeds are very important because they feed all animals. If there were no seaweeds, there would be no fish or shellfish," he said.

Sergio Gutierrez, a Changa seaweed harvester who works gathering the algae, drying it and bundling it to sell, said the marine forests were a key part of the community.

"They are the livelihood for our households and much more," he said.

With all the benefits the underwater forests provide for the environment and community, marine biologist Gonzalez says more policies to protect the forests are needed.

"All the marine organisms associated with (the forests) depend on their existence, so do humans," Gonzalez said. "These forests maintain temperatures, create a natural breakwater effect, and keep the ecosystem stable."