Concede, humanity: these tiny organisms that live underwater in low-light conditions seem to have outsmarted us. They have mastered the quantum world we are struggling to understand.
We have known for some time that photosynthetic organisms harness the power of quantum coherence, but researchers in Australia have recently discovered that some cryptophytes, which are a type of algae, have developed a genetic switch that allows them to turn the "quantumness" in their photosynthetic processes on and off. Studying the differences between the types of cryptophytes that are using quantum mechanics to photosynthesize and the ones that aren't could yield new and invaluable insights into exactly what role quantum coherence is playing in the process that sustains all life on Earth. Go phytoplankton.
"Once a light-harvesting protein has captured sunlight, it needs to get that trapped energy to the reaction centre in the cell as quickly as possible, where the energy is converted into chemical energy for the organism. "It was assumed the energy gets to the reaction centre in a random fashion, like a drunk staggering home. But quantum coherence would allow the energy to test every possible pathway simultaneously before travelling via the quickest route." In the new study, the team used x-ray crystallography to work out the crystal structure of the light-harvesting complexes from three different species of cryptophytes. They found that in two species a genetic mutation has led to the insertion of an extra amino acid that changes the structure of the protein complex, disrupting coherence. "This shows cryptophytes have evolved an elegant but powerful genetic switch to control coherence and change the mechanisms used for light harvesting," says Professor Curmi.