Global estimates of the extent and production of macroalgal forests

• Published in: Global Ecology and Biogeography
• Main Authors: Duarte, Carlos M., Gattuso, Jean-Pierre, Hancke, Kasper, Gundersen, Hege, Filbee-Dexter, Karen, Pedersen, Morten F., Middelburg, Jack J., Burrows, Michael T., Krumhansl, Kira A., Wernberg, Thomas, Moore, Pippa, Pessarrodona, Albert, Ørberg, Sarah B., Pinto, Isabel S., Assis, Jorge, Queirós, Ana M., Smale, Dan A., Bekkby, Trine, Serrão, Ester A., Krause-Jensen, Dorte
• Other Authors: Marine Science Program, Red Sea Research Center (RSRC), Biological and Environmental Science and Engineering (BESE) Division, Arctic Research Centre Aarhus University Århus C Denmark, Laboratoire d'Océanographie de Villefranche Sorbonne Université CNRS Villefranche-sur-mer France, Institute for Sustainable Development and International Relations Sciences Po Paris France, Norwegian Institute for Water Research (NIVA) Oslo Norway, UWA Oceans Institute & School of Biological Sciences University of Western Australia Crawley Western Australia Australia, Department of Science and Environment Roskilde University Roskilde Denmark, Department of Earth Sciences Utrecht University Utrecht The Netherlands, Scottish Association for Marine Science Scottish Marine Institute Oban UK, Fisheries and Oceans Canada Bedford Institute of Oceanography Dartmouth Nova Scotia Canada, Institute of Biological, Environmental and Rural Sciences Aberystwyth University Aberystwyth UK, Department of Bioscience Aarhus University Silkeborg Denmark, Ciimar/CIMAR and Faculty of Sciences University of Porto Porto Portugal, CCMAR Universidade do Algarve Campus de Gambelas Faro Portugal, Plymouth Marine Laboratory Plymouth UK, Marine Biological Association of the United Kingdom Plymouth UK
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2022
• Subjects: Arctic
• Online Access: http://hdl.handle.net/10754/676668; https://doi.org/10.1111/geb.13515

Aim- Macroalgal habitats are believed to be the most extensive and productive of all coastal vegetated ecosystems. In stark contrast to the growing attention on their contribution to carbon export and sequestration, understanding of their global extent and production is limited and these have remained poorly assessed for decades. Here we report a first data-driven assessment of the global extent and production of macroalgal habitats based on modelled and observed distributions and net primary production (NPP) across habitat types. Location- Global coastal ocean. Time period- Contemporary. Major taxa studied- Macroalgae. Methods- Here we apply a comprehensive niche model to generate an improved global map of potential macroalgal distribution, constrained by incident light on the seafloor and substrate type. We compiled areal net primary production (NPP) rates across macroalgal habitats from the literature and combined this with our estimates of the global extent of these habitats to calculate global macroalgal NPP. Results- We show that macroalgal forests are a major biome with a global area of 6.06–7.22 million km2, dominated by red algae, and NPP of 1.32 Pg C/year, dominated by brown algae. Main conclusions- The global macroalgal biome is comparable, in area and NPP, to the Amazon forest, but is globally distributed as a thin strip around shorelines. Macroalgae are expanding in polar, subpolar and tropical areas, where their potential extent is also largest, likely increasing the overall contribution of algal forests to global carbon sequestration. We thank Chris Jenkins at the Institute of Arctic & Alpine Research (INSTAAR), University of Colorado at Boulder, USA, and Eleonora Manca at the Joint Nature Conservation Committee, UK, for providing substrate data for the evaluation of the global map of the maximum extent of macroalgal distribution. Research for this paper was supported by Euromarine (http://www.euromarinenetwork.eu). We also received support from FCT – Foundation for Science and Technology ...