Scientist Dr. Jared Leadbetter rinsed a glass jar of pink manganese in the sink. Then he left it there. It soaks . . . and soaks . . . and soaks. Ten weeks pass. Dr. Leadbetter returns to his California lab. He has two questions. One: “What is that dark stuff coating my jar?” Two: “Who ate my manganese?”

Manganese is a hard metal. It exists all over in Earth’s crust and surface. People use it to make steel and glass. It strengthens the aluminum in soda cans. Animals and humans carry this mineral element in their bodies. God designed it to help bones develop and wounds heal. So manganese is nothing unusual or new. But a manganese muncher? That’s totally strange!

The hard, dark metal in Dr. Leadbetter’s jar was oxidized (digested) manganese. Dr. Leadbetter thought fast. He decided not to wash the jar’s water down the sink. He kept the manganese-hungry culprits—tap water bacteria—trapped inside. What kind of creatures could they be? What kind of bacteria eat metal for breakfast? Dr. Leadbetter and another scientist, Hang Yu, studied them. And of course they gave them a name. Introducing . . . Candidatus Manganitrophus noduliformans and Ramlibacter lithotrophicus. They are the first bacteria ever known to get energy from manganese.

The discovery could help solve some mysteries. More bacteria like these live in groundwater. Water systems often become clogged by manganese oxides. The newfound bacteria may get the blame for that.

Another manganese head-scratcher: Grapefruit-sized manganese oxide balls roll around the ocean floor. Dr. Leadbetter thinks these bacteria may form them.

Scientists wondered for more than 100 years if manganese-eating bacteria might exist. Now they have found them by accident. The lesson? Sometimes it pays to leave the dishes in the sink!