Scientists are turning the ocean pink in the US city of San Diego to find out how river currents mix with ocean water and how freshwater and marine pollution travels. They dye the water pink as it flows from the estuary. Then track it with drones and special sensors and even a jet ski fitted with a fluorometer which measures the light from the dye. Ocean plastic makes up 80% of all marine pollution. There are around 24 trillion microscopic pieces of plastic in the ocean weighing up to 578,000 tonnes, that’s equivalent to 4,000 blue whales. Watch the video to learn more about how dying the waters pink can help scientists detect or stop marine pollution.