AdvertisementScientists Use Antacid To Help Measure The Rate Of Reef GrowthMarch 22, 2013Richard HarrisfacebookEmailKen Caldeira of the Carnegie Institution for Science takes a water sample during his experiment out on part of the Great Barrier Reef. The water is slightly pink because his team is using a dye to trace an acid-neutralizing chemical as it flows across the reef. (NPR)