Percorrer por autor "Krumhansl, Kira A."
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- Carbon export from seaweed forests to deep ocean sinksPublication . Karen Filbee-Dexter; Pessarrodona, Albert; Pedersen, Morten F.; Wernberg, Thomas; Duarte, Carlos M.; Assis, Jorge; Bekkby, Trine; Burrows, Michael T.; Carlson, Daniel F.; Gattuso, Jean-Pierre; Gundersen, Hege; Hancke, Kasper; Krumhansl, Kira A.; Kuwae, Tomohiro; Middelburg, Jack J.; Moore, Pippa J.; Queirós, Ana M.; Smale, Dan A.; Sousa-Pinto, Isabel; Suzuki, Nobuhiro; Krause-Jensen, DorteThe coastal ocean represents an important global carbon sink and is a focus for interventions to mitigate climate change and meet the Paris Agreement targets while supporting biodiversity and other ecosystem functions. However, the fate of the flux of carbon exported from seaweed forests—the world’s largest coastal vegetated ecosystem—is a key unknown in marine carbon budgets. Here we provide national and global estimates for seaweed-derived particulate carbon export below 200 m depth, which totalled 3–4% of the ocean carbon sink capacity. We characterized export using models of seaweed forest extent, production and decomposition, as well as shelf–open ocean water exchange. On average, 15% of seaweed production is estimated to be exported across the continental shelf, which equates to 56 TgC yr−1 (range: 10–170 TgC yr−1). Using modelled sequestration timescales below 200 m depth, we estimated that each year, 4–44 Tg seaweed-derived carbon could be sequestered for 100 years. Determining the full extent of seaweed carbon sequestration remains challenging, but critical to guide efforts to conserve seaweed forests, which are in decline globally. Our estimate does not include shelf burial and dissolved and refractory carbon pathways; still it highlights a relevant potential contribution of seaweed to natural carbon sinks.
- Global estimates of the extent and production of macroalgal forestsPublication . 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; Serrao, Ester; Krause‐Jensen, Dorte; Field, RichardAim 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 km(2), 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.