Mauzerall says, "A spinach leaf sounds different than a lettuce leaf. One species of algae will sound different from another. A healthy plant will sound different than a stressed one." "I send a pulse of light through a leaf in water and the energy that's not absorbed expands in the water and creates sound waves. It's not new. Bell modulated light to create sound waves."
Stutz explains. "In 1880, four years after he perfected his telephone, Alexander Graham Bell decided that transmitting voice by light would be far more effective than electrical transmission over wires. He designed a system in which sound waves hitting a sunlit mirror were reflected as light waves. (Wow!) The recaptured light could then be reconstituted as sound. It worked - when the sun was out and when there was no interference. A hundred years later lasers beamed through fiber-optic cable allowed the fine control necessary to transmit sound at the speed of light."
Stutz continues. "Mauzerall's device was far simpler but its larger applications might ennable scientists to tune in on the photosynthesis of a forest to find out the state of its health."
Stutz asks Mauzerall what he hears. "I hear the whoosh of just-created oxygen." Listen to the whoosh. It's why we are here.