You may not realize it, but you have the ability to hear plants harnessing the sun’s energy to perform the reaction of photosynthesis. All you have to do is take a dive under water and listen carefully for the distinct “ping” noise made while down there. New studies have found that this “ping” is the sound that underwater plants, such as red algae, make when performing photosynthesis.

Montastraea annularis (boulder star coral) (San Salvador Island, Bahamas) 1

Algae and other underwater plants perform photosynthesis just like any other land plant. What this means is that they use the sun’s rays to chemically convert carbon dioxide and water into a sugar used for plant energy and oxygen as a waste product that flows throughout the planets atmosphere. In the underwater atmosphere, these oxygen molecules are tiny bubbles that race upwards in the water. Researchers have found that when these oxygen bubbles disconnect from the plants they make a sudden “ping” noise.

The noise was first recognized by researchers in Hawaii when the Hakai Magazine reported that healthy and protected coral reefs were making low frequency sounds, while damaged coral reefs were making higher pitched sounds.

One researcher from this magazine, Simon Freeman, said that “there seemed to be a correlation between the sound and the proportion of algae covering the sea floor.” To test this assumption, Freeman and his team transferred 22lbs of invasive red algae from the Hawaiian bay to a tank filled with sea water in attempt to hear the pinging sound without the noisy distractions of the ocean. As it turned out, this research team heard the same high frequency pings from this algae as they did from the distressed reefs.

Researchers claim that a large part of corals’ distress comes from all the algae that are smothering the corals, and this is why the distressed corals had a higher frequency noise: they had more algae covering its surface that perform photosynthesis and produce these oxygen bubbles. They believe with this finding that monitoring the sounds of the oxygen bubbles could be a fast and less invasive way of keeping track of the health of coral reefs.

This connects to what we have learned in AP Bio as in the process of photosynthesis, the chlorophyll of a plant absorbs light energy called photons, which excites the chlorophyll. The excited chlorophyll pass the photons from one chlorophyll to another until the energy reaches a special chlorophyll in the reaction complex center of Photosystem II known as the p680 chlorophyll. Once the photon reachers this special chlorophyll, p680 donates an electron to the primary electron acceptor in the thylakoid membrane to start the electron transport chain. In order to replace this donated electron, water molecules (one of the reactants of photosynthesis) are quickly split up resulting in an electron and replace the donated one, hydrogen, and oxygen as a waste product. This oxygen that is released at this point of the photosynthesis process is the oxygen that is released from all plants, including the underwater plants like the algae, when they perform photosynthesis. It is waste oxygen that is released from the algae underwater that forms the oxygen bubbles that detach from the plants and float upwards, and eventually make the “ping” noise underwater that you can hear when you dive in. Moreover, when we say you can “hear photosynthesis,” what you are really hearing is the oxygen bubbles created as a waste product of photosynthesis when they detach from the plants.

When going out to a beach and diving underwater, I would sometimes find myself hearing a faint little pinging or bubble popping noise. Could this noise I am hearing be the oxygen bubbles from the photosynthesis of underwater plants? What do you think?

Print Friendly, PDF & Email