Researchers from the Max Planck Institute for Marine Microbiology have recently established that seagrasses produce and release truly staggering amounts of sugar into the environment.
During the course of their study, the team determined that while the seagrass Posidonia oceanica excretes sugars – sucrose mainly – into its rhizosphere, it also produces phenolic compounds which inhibit microbial consumption of that sucrose, thus leading to the sugars accumulating into concentrations "nearly 80 times higher than previously observed in marine environments".
"To put this into perspective: We estimate that worldwide there are between 0.6 and 1.3 million tons of sugar, mainly in the form of sucrose, in the seagrass rhizosphere". Manuel Liebeke, head of the Research Group Metabolic Interactions at the Max Planck Institute for Marine Microbiology, said as quoted by Phys.org. "That is roughly comparable to the amount of sugar in 32 billion cans of Coke".
As Nicole Dubilier, director at the Max Planck Institute for Marine Microbiology, explained, seagrasses produce sugar during photosynthesis, and while "under average light conditions, these plants use most of the sugars they produce for their own metabolism and growth", the high light conditions cause them to "produce more sugar than they can use or store".
"Then they release the excess sucrose into their rhizosphere", she added. "Think of it as an overflow valve".
The sucrose that ends up there also helps trap carbon that would otherwise be released into the atmosphere, and the destruction of seagrass meadows may not bode well for the environment, with the media outlet pointing out that seagrasses are "rapidly declining in all oceans".
"Our calculations show that if the sucrose in the seagrass rhizosphere was degraded by microbes, at least 1.54 million tons of carbon dioxide would be released into the atmosphere worldwide", Liebeke said. "That's roughly equivalent to the amount of carbon dioxide emitted by 330,000 cars in a year".