Scientists have found a way to use microorganisms called water fleas to help filter harmful chemicals and pollutants out of water. Water fleas are not actually fleas like the ones that bite poor Fido. They are actually teeny tiny crustaceans (the group of animals that includes shrimp, lobsters, and crabs) from a genus called Daphnia. Daphnia are filter feeders, which means they take in everything around them in the water and strain it out to get their food.
Scientists realized they could harness this power to get Daphnia to clean water for humans. Daphnia are very good at sucking up chemicals that would be harmful for us to drink, and they themselves remain unharmed. So far, experiments with Daphnia have shown very good results. Scientists are hopeful that Daphnia might be used in the future as a cheap and eco-friendly way to clean water in large cities or in developing countries.