Their love for metals comes from their peculiar metabolism, scientists explain. To transform nutrients into a suitable chemical form, living organisms need to dump an excess of electrons, which is called respiration. Humans use oxygen for the process, but many microbes living in environments with little oxygen use other mechanisms. Shewanella use metals as electron acceptors, reducing them in the process.

However the boost of speed bacteria get was unexpected, authors say.

“As far as we know, it is new behavior,” says study co-author and microbiologist Ken Nealson. “It’s a new way of thinking about what bacteria do. The really great thing is that it’s probably opened up 10 times more questions and created 10 times more hypotheses than we had when we started.”

Experiments with electrodes confirm that the behavior is electrochemical in nature. Researchers also discovered special proteins on the bacteria surface, which they believe serves as wiring for conducting electrons out.

While much research is needed to study Shewanella and its peculiar metabolism, the team hopes they will be able to use it to design better microbial fuel cells, which will harness these electron-shuttling bacteria to produce energy.