Year: 2026
Type: preprint
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.
Authors: Inga Hellige, Hagen Buck-Wiese, Margot Bligh, Timothy Thomson, Lydia White, Carol Arnosti, Dariya Baiko, Linda Biehler, Mar Fernández-Méndez, Sherif Ghobrial, Bowei Gu, Camilla Gustafsson, Mohammed Kajee, C. Chad Lloyd, Nguyen P. Nguyen, Miriam Philippi, Dan Potin, Philippe Potin, Mark Rothman, Beatriz S. Murillo, Michael Seidel, Catharina Uth, Evie Wieters, Marie Magnusson, Jan-Hendrik Hehemann
Institutions: University of Bremen, Max Planck Institute for Marine Microbiology, University of Southern California, University of Waikato, University of Helsinki, University of North Carolina at Chapel Hill, Carl von Ossietzky Universität Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, University of Cape Town, Centre National de la Recherche Scientifique, Station Biologique de Roscoff, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins, Department of Forestry, Fisheries and the Environment, Pontificia Universidad Católica de Chile
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Tertiary Education Commission, University of Waikato, Deutsche Forschungsgemeinschaft, Agence Nationale de la Recherche, Ella ja Georg Ehrnroothin Säätiö, Jane ja Aatos Erkon Säätiö, Universidad Nacional Autónoma de México, University of Cape Town, Universität Bremen, Agencia Nacional de Investigación y Desarrollo, Department of Forestry, Fisheries and the Environment, Directorate for Biological Sciences
Awards: EXC 2077: Der Ozeanboden – unerforschte Schnittstelle der Erde, MECHANISMS THAT BREAKDOWN AND REINFORCE FEEDBACKS AND ALTERNATIVE PATCH STATES IN CONTRASTING SHALLOW COASTAL COMMUNITIES, G3655129345, G3794429855, G4636844104, NUCLEO MILENIO PARA LA ECOLOGIA Y CONSERVACION DE LOS ECOSISTEMAS DE ARRECIFES MESOFOTICOS TEMPLADOS, A mechanistic microbial underpinning for the size-reactivity continuum of dissolved organic carbon degradation, G7240651115, G7454332079, REINFORCING FEEDBACKS IMMERSED IN REALWORLD COMPLEXITY THE ECOLOGICAL NETWORKS MAINTAINING ALTERNATIVE COMMUNITY LANDSCAPES, Substrate structural complexity and abundance control distinct mechanisms of microbially-driven carbon cycling in the ocean
OpenAlex ID: W7168178673