Inga Hellige1,2, Hagen Buck-Wiese1,2,3, Margot Bligh1,2, Timothy Thomson4, Lydia White5, Carol Arnosti6, Dariya Baiko7, Sherif Ghobrial6, Camilla Gustafsson5, Mohammed Kajee8, Chad C. Lloyd6, Catharina Uth9,5, Dan Potin10, Mark Rothman8,11, Beatriz S. Murillo12,13, Michael Seidel7, Evie Wieters12,13, Marie Magnusson4, Jan-Hendrik Hehemann1,2
1University of Bremen, Germany - 2Max-Planck Institute for Marine Microbiology, Germany - 3University of Southern California, USA - 4University of Waikato, New Zealand - 5University of Helsinki, Finland - 6University of Northern Carolina, USA - 7Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Germany - 8University of Cape Town, South Africa - 9Tvärminne Zoolgical Station, Finland - 10CNRS Sorbonne University, Station Biologique Roscoff, France - 11Department of Environment, Forestry and Fisheries, South Africa - 12Estación Costera de Investigaciones Marinas, Chile - 13Universidad Católica de Chile, Chile
Fucoidan secretion by brown algae may be a substantial pathway of carbon storage in the ocean. The geographic and phylogenetic distribution of fucoidan exudation by brown algae is unknown. Here, we show significant fucoidan secretion by six brown algae species from two families in six georegions. Brown algae invested up to 4% of their fixed carbon into the synthesis of exudated fucoidan. Fucoidan secretion contributed 20-50% to the released dissolved organic carbon. Based on the observed positive correlation between macroalgal biomass and fucoidan secretion rates, we calculate a global secretion of up to 0.1 Gt carbon as fucoidan by brown algae per year. Dissolved fucoidan was stable against immediate microbial consumption and coagulated into particles, constituting a pathway of carbon removal from the surface ocean. Given the broad geographic range of various brown algae species, preserving and enhancing brown algae abundance can be used as a nature-based solution for carbon sequestration.
Biography
Inga Hellige is a last year PhD candidate working in the Glycobiochemistry and Carbon Sequestration Group at MARUM Center for Marine Environmental Sciences at University of Bremen and Max-Planck Institute for Marine Microbiology, Bremen, Germany. She is researching brown algae exudates as potential carbon sinks across the globe by performing six mesocosm studies with different brown algae species.