Can glowing bacteria tell you how polluted water is? Some ocean bacteria produce their own light through a process called bioluminescence. When pollutants harm the bacteria, their glow fades. You transfer bioluminescent bacteria into test tubes using a sterilized metal loop. Then you add different pollutants one at a time: - hair gel - 3-in-1 oil - tap water - Hudson River water To measure each effect, you count how many sheets of paper it takes to block the glow. Hair gel cut the light by 75 percent. Tap water and river water each reduced it by 20 percent. The 3-in-1 oil had no effect at all.