Researchers from the Max Planck Institute for Marine Microbiology report that mountains of sugar have been discovered hidden under seagrass beds across the world’s oceans.
Seagrass beds are among the best carbon-capturing ecosystems — a single square kilometer of seagrass stores almost twice as much carbon as terrestrial forests at a rate 35 times faster, according to the Institute.
To better understand these carbon sequestration powerhouses, scientists conducted a study off the Italian island of Elba where they collected samples of seagrass beds and their surrounding sediments. Their data revealed that sugar concentrations beneath seagrass beds were at least 80 times higher than those found in other marine ecosystems.
“To put this into perspective: we estimate that there are between 0.6 and 1.3 million tonnes of sugar in the world, mainly in the form of sucrose,” said Manuel Liebeke, a scientist at the Institute, in a statement. Press release.
“That’s roughly comparable to the amount of sugar in 32 billion cans of Coke!”
Lush seagrass beds in the Mediterranean Sea. (HYDRA Marine Sciences GmbH/ Max Planck Institute for Marine Microbiology)
__UNDERSTANDING THE ROLE OF MICRO-ORGANISMS __
Seagrasses consume significant levels of carbon dioxide due to their symbiotic relationship with bacteria in which both species benefit from each other.
Sunlight allows the plant to capture carbon dioxide from water and convert it into sugar molecules, which are made up of carbon, hydrogen and oxygen. During periods of maximum sunlight, such as early afternoon or the summer season, plants produce more sugar than they need, so they store the extra sucrose around their roots in the bottom. marine.
Bacteria living around the roots of plants consume this sugar, giving them energy to produce more nutrients, such as nitrogen, which fertilize seagrass beds. This symbiotic relationship was first documented by the research team and was published in Nature ecology and evolution.
A scientist from the Max Planck Institute for Marine Microbiology in Bremen collects sucrose from a seagrass meadow. (HYDRA Marine Sciences GmbH/ Max Planck Institute for Marine Microbiology)
The study reported that the giant piles of excess sugar were not consumed by bacteria due to the phenolic compounds released by the seagrass, which cannot be digested by many microorganisms. This was a key finding for the researchers, as it confirms that the carbon in the sugar stays in these underwater ecosystems and out of the atmosphere.
Research has indicated that if microorganisms consumed the sucrose stored by the roots of seagrasses, at least 1.54 million tonnes of carbon dioxide would be released into the atmosphere, which is equivalent to the carbon emissions of 330,000 cars. in one year.
HABITATS AT RISK
The herbaria represent 10 percent of the carbon storage capacity of the ocean even though it only covers 0.2% of the seabed. The researchers reported that despite the critical role seagrasses play in the global carbon cycle, they are in rapid decline due to coastal developments and stressors imposed by climate change.
Up to 33% of the world’s seagrass beds may have already been lost, which the Institute says is “comparable to the loss of coral reefs and tropical rainforests”.
“Our study contributes to our understanding of one of our planet’s most critical coastal habitats and highlights how important it is to preserve these blue carbon ecosystems,” said study first author Maggie Sogin. in the press release.
Thumbnail: A Mediterranean seagrass (Posidonia oceanica) in the south of France. (Arnaud Abadie/E+/Getty Images)