Widespread attraction of marine bacteria to the macroalgae-derived polysaccharide fucoidan
Fucoidan is the second most abundant polysaccharide in brown macroalgae, contributing up to 50% of the dissolved organic matter released daily from these algae into the ocean, substantially influencing the marine carbon cycle. Due to its complex chemical structure, fucoidan is highly resistant to microbial degradation and accumulates on the surface of macroalgae, where it contributes to…
Fucoidan, a polysaccharide found in brown macroalgae, makes up to half of the dissolved organic matter released into the ocean daily. This complex molecule, due to its resistance to microbial breakdown, adheres to the surface of macroalgae and plays a role in managing their microbial communities. Researchers utilized microfluidic assays to study how marine bacteria react to fucoidan produced by two types of brown macroalgae.
Their findings indicate that all tested bacterial strains, out of 14, were drawn to fucoidan when concentrations were high (0.1 to 1 mg/mL), similar to the levels found near the algae. At lower concentrations, there was either no reaction or a slight repulsion. Even though fucoidan did not promote bacterial growth under these conditions, it did not hinder the use of other carbon sources.
These results suggest that fucoidan gradients function as chemical signals, guiding marine bacteria towards the nutrient-rich environment around macroalgal surfaces. This could imply that fucoidan has an ecological impact on the macroalgal microbiota, bacterial behavior, and ultimately, carbon cycling in the ocean.
Written by urgent.news from bioRxiv's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
