Algae are microscopic, single-celled plants, separated from us by over 700 million years of evolutionary divergence. We are so different, and yet, on one very basic level, we are the same. We both use electrical signaling to sense, react to, and communicate about our environments. We share a common language.

In humans, electrical action potentials (APs) underlie the firing of the neurons in our brains and nervous systems, allowing to think, feel, move, and interact. In algae, too, APs support essential life processes – from photosynthesis to reproduction to, in some cases, creating their own light. This phenomenon, known as bioluminescence, occurs when algae are mechanically stimulated and is thought to function as a defense mechanism. But it is also extremely beautiful to behold, serving as an illuminating reminder of sentience where we least expect it.