Bioluminescent phytoplankton light up rolling surf during a so-called red tide event along the coast of Leucadia, California, in September 2011. Red tides—often rusty-hued in daylight—can occur all over the world and are caused by large-scale algae blooms.
Some red tides, like the one shown here, contain phytoplankton that emit bursts of light when agitated.
In the recent study, published last October in the Proceedings of the National Academy of Sciences, the team confirmed the existence of channels in dinoflagellates that allow only protons—positively charged particles—to pass through. (Related: "Proton Smaller Than Thought—May Rewrite Laws of Physics.")
"The newly discovered channel had just the right properties needed to trigger the flash," said study co-author Thomas DeCoursey, an electrophysiologist at Rush University in Chicago. "If you replaced the dinoflagellate channel with the [corresponding cell] channel from humans or mice or snails, it could not do the job."
The study authors propose that, as dinoflagellates float, movement in the surrounding water sends electrical impulses around a proton-filled compartment inside the microorganisms.
The electrical pulses open the voltage-sensitive proton channels, triggering a series of chemical reactions, which ultimately activate a protein called luciferase that produces the neon blue light.