Plastic pollution, overfishing, and climate change are all taking an enormous toll on the planet’s life-support system. The oceans are acidifying, sea levels are rising, and coral reefs home to myriad fish species are dying.
But it’s not all doom and gloom.
Scientists, activists, and ordinary citizens are rallying to protect the oceans and pushing to make huge swaths of the most sensitive marine areas off-limits to oil and gas drilling and other potentially destructive developments. New technologies are proving crucial in that fight.
Here are five high-tech solutions that are helping to save the seas.
Read more about the fight to save the world's oceans in our Blue Planet series.