Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 120, Issue 1, Pages -Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.2210561119
Keywords
blue carbon; brown macroalgae; fucoidan; carbon sequestration; marine carbon cycle
Categories
Funding
- European Union [730984]
- DFG [HE 7217/1-1]
- Cluster of Excellence initiative [390741603]
Ask authors/readers for more resources
Brown algae have the ability to convert a large amount of carbon dioxide into fucoidan, a complex polysaccharide. Through improved techniques, it has been found that brown algae secrete 0.3% of their biomass as fucoidan per day, with a secretion rate ranging from 28 to 40 mg C kg-1 h-1.
Brown algae annually convert gigatons of carbon dioxide into carbohydrates, including the complex extracellular matrix polysaccharide fucoidan. Due to its persistence in the environment, fucoidan is potentially a pathway for marine carbon sequestration. Rates of fucoidan secretion by brown algae remain unknown due to the challenge of identifying and quantifying complex polysaccharides in seawater. We adapted the techniques of anion exchange chromatography, enzyme-linked immunosorbent assay, and biocatalytic enzyme-based assay for detection and quantification of fucoidan. We found the brown alga Fucus vesiculosus at the Baltic Sea coast of south-west Finland to secrete 0.3% of their biomass as fucoidan per day. Dissolved fucoidan concentrations in seawater adjacent to algae reached up to 0.48 mg L-1. Fucoidan accumulated during incubations of F. vesiculosus, significantly more in light than in darkness. Maximum estimation by acid hydrolysis indicated fucoidan secretion at a rate of 28 to 40 mg C kg-1 h-1, accounting for 44 to 50% of all exuded dissolved organic carbon. Composed only of carbon, oxygen, hydrogen, and sulfur, fucoidan secretion does not consume nutrients enabling carbon sequestration independent of algal growth. Extrapolated over a year, the algae sequester more carbon into secreted fucoidan than their biomass. The global utility of fucoidan secretion is an alternative pathway for carbon dioxide removal by brown algae without the need to harvest or bury algal biomass.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available