Macroalgal fucoidan can activate the biological carbon pump
Abstract
Macroalgae secrete complex carbohydrate polymers, their extracellular matrix, as protection against microbial degradation. By resisting breakdown, these carbohydrates can contribute to marine carbon sequestration, though mechanisms, extent, and timescales remain unknown. Using ship-based sampling and experiments, we found that brown macroalgae release 1.7-4.2% of carbon fixation as fucoidan, equivalent to 0.32-0.88 mg fucoidan per gram of dry seaweed tissue per day.
A Bayesian model trained on our empirical data, coupled with Monte Carlo simulations suggests an annual global release of 13-37 megatons fucoidan carbon. Moreover, degradation resistance combined with surface-activity enabled fucoidan to act as glue that cross-linked allochthonous organic carbon including microbes and proteins into marine snow. Notably, substantial fucoidan exudation was universally conserved across all tested species and regions. Thus, any brown macroalgal species can be used e.g. via aquafarming to enhance the formation of marine snow.
MainRemnants of a molecular arms race in the sunlit ocean bury carbon for centuries in the ocean floor 1 . This arms race starts with diverse photosynthetic algae, which collectively fix about 45 gigatons
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BibTeX
@misc{hellige2026macroalgal,
title = {{Macroalgal fucoidan can activate the biological carbon pump}},
author = {Inga Hellige and Hagen Buck-Wiese and Margot Bligh and Timothy Thomson and Lydia White and Carol Arnosti and Dariya Baiko and Linda Biehler and Mar Fernández-Méndez and Sherif Ghobrial and Bowei Gu and Camilla Gustafsson and Mohammed Kajee and C. Chad Lloyd and Nguyen Nguyen and Miriam Philippi and Dan Potin and Philippe Potin and Mark Rothman and Beatriz Murillo and Michael Seidel and Catharina Uth and Evie Wieters and Marie Magnusson and Jan-Hendrik Hehemann},
howpublished = {HAL},
year = {2026},
month = jul,
doi = {10.64898/2026.07.10.737761},
url = {https://hal.science/hal-05769978v1},
note = {CC BY-ND 4.0},
}
RIS
TY - UNPB
TI - Macroalgal fucoidan can activate the biological carbon pump
AU - Inga Hellige
AU - Hagen Buck-Wiese
AU - Margot Bligh
AU - Timothy Thomson
AU - Lydia White
AU - Carol Arnosti
AU - Dariya Baiko
AU - Linda Biehler
AU - Mar Fernández-Méndez
AU - Sherif Ghobrial
AU - Bowei Gu
AU - Camilla Gustafsson
AU - Mohammed Kajee
AU - C. Chad Lloyd
AU - Nguyen Nguyen
AU - Miriam Philippi
AU - Dan Potin
AU - Philippe Potin
AU - Mark Rothman
AU - Beatriz Murillo
AU - Michael Seidel
AU - Catharina Uth
AU - Evie Wieters
AU - Marie Magnusson
AU - Jan-Hendrik Hehemann
PY - 2026
DA - 2026/07/13
PB - HAL
DO - 10.64898/2026.07.10.737761
UR - https://hal.science/hal-05769978v1
AB - Macroalgae secrete complex carbohydrate polymers, their extracellular matrix, as protection against microbial degradation. By resisting breakdown, these carbohydrates can contribute to marine carbon sequestration, though mechanisms, extent, and timescales remain unknown. Using ship-based sampling and experiments, we found that brown macroalgae release 1.7-4.2% of carbon fixation as fucoidan, equivalent to 0.32-0.88 mg fucoidan per gram of dry seaweed tissue per day. A Bayesian model trained on our empirical data, coupled with Monte Carlo simulations suggests an annual global release of 13-37 megatons fucoidan carbon. Moreover, degradation resistance combined with surface-activity enabled fucoidan to act as glue that cross-linked allochthonous organic carbon including microbes and proteins into marine snow. Notably, substantial fucoidan exudation was universally conserved across all tested species and regions. Thus, any brown macroalgal species can be used e.g. via aquafarming to enhance the formation of marine snow. MainRemnants of a molecular arms race in the sunlit ocean bury carbon for centuries in the ocean floor 1 . This arms race starts with diverse photosynthetic algae, which collectively fix about 45 gigatons
ER -