Natures wonders: phytoplankton special sugar (Introduction)

by David Turell , Friday, February 19, 2021, 20:33 (1371 days ago) @ David Turell

Part of the carbon cycle protection:

https://phys.org/news/2021-02-sweet-marine-particles-resist-hungry.html

"A major pathway for carbon sequestration in the ocean is the growth, aggregation and sinking of phytoplankton—unicellular microalgae like diatoms. Just like plants on land, phytoplankton sequester carbon from atmospheric carbon dioxide. When algae cells aggregate, they sink and take the sequestered carbon with them to the ocean floor. This so called biological carbon pump accounts for about 70 per cent of the annual global carbon export to the deep ocean. Estimated 25 to 40 per cent of carbon dioxide from fossil fuel burning emitted by humans may have been transported by this process from the atmosphere to depths below 1000 meter, where carbon can be stored for millennia.

"Yet, even it is very important, it is still poorly understood how the carbon pump process works at the molecular level. Scientists...investigate in this context marine polysaccharides—meaning compounds made of multiple sugar units—which are produced by microalgae. These marine sugars are very different on a structural level and belong to the most complex biomolecules found in nature. One single bacterium is not capable to process this complex sugar-mix. Therefore a whole bunch of metabolic pathways and enzymes is needed. In nature, this is achieved by a community of different bacteria that work closely and very efficiently together—a perfect coordinated team. This bacterial community works so well that the major part of microalgal sugars are degraded before they aggregate and start to sink. A large amount of the sequestered carbon therefore is released back into the atmosphere.

"But, how is it possible that nevertheless a lot of carbon is still transported to the deep-sea? The scientists of the group Marine Glycobiology now revealed a component that may be involved in this process and published their results in the journal Nature Communications. "We found a microalgal fucose-containing sulphated polysaccharide, in short FCSP, that is resistant to microbial degradation," says Silvia Vidal-Melgosa, first author of the paper.

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"The discovery of FCSP in diatoms, with demonstrated stability and adhesive properties, provides a previously uncharacterised polysaccharide that contributes to particle formation and potentially therefore to carbon sequestration in the ocean. One of the next steps in the research is "to find out, if the particles of this sugar exist in the deep ocean," says Hehemann. "That would indicate that the sugar is stable and constitutes an important player of the biological carbon pump." Furthermore, the observed stability against bacterial degradation, and the structure and physicochemical behavior of diatom FCSP points towards specific biological functions. "Given its stability against degradation, FCSP, which coats the diatom cells, may function as a barrier protecting the cell wall against microbes and their digestive enzymes," says Hehemann. And last but not least, another open question to be solved: These sugar particles were found n the North Sea near the island of Helgoland. Do they also exist in the sea of other regions in the world?"

Comment: Current incomplete research, but it features the discovery of a special sugar which fights hungry bacteria to protect the vital carbon cycle on Earth. Could be a God designed molecule to help this econiche work properly.