Browsing by Author "Smale, Dan A."
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- 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.
- Global seaweed productivityPublication . Pessarrodona, Albert; Assis, Jorge; Filbee-Dexter, Karen; Burrows, Michael T.; Gattuso, Jean-Pierre; Duarte, Carlos M.; Krause-Jensen, Dorte; Moore, Pippa J.; Smale, Dan A.; Wernberg, ThomasThe magnitude and distribution of net primary production (NPP) in the coastal ocean remains poorly constrained, particularly for shallow marine vegetation. Here, using a compilation of in situ annual NPP measurements across >400 sites in 72 geographic ecoregions, we provide global predictions of the productivity of seaweed habitats, which form the largest vegetated coastal biome on the planet. We find that seaweed NPP is strongly coupled to climatic variables, peaks at temperate latitudes, and is dominated by forests of large brown seaweeds. Seaweed forests exhibit exceptionally high per-area production rates (a global average of 656 and 1711 gC m-2 year-1 in the subtidal and intertidal, respectively), being up to 10 times higher than coastal phytoplankton in temperate and polar seas. Our results show that seaweed NPP is a strong driver of production in the coastal ocean and call for its integration in the oceanic carbon cycle, where it has traditionally been overlooked.
- The future of Blue Carbon sciencePublication . Macreadie, Peter I.; Anton, Andrea; Raven, John A.; Beaumont, Nicola; Connolly, Rod M.; Friess, Daniel A.; Kelleway, Jeffrey J.; Kennedy, Hilary; Kuwae, Tomohiro; Lavery, Paul S.; Lovelock, Catherine E.; Smale, Dan A.; Apostolaki, Eugenia T.; Atwood, Trisha B.; Baldock, Jeff; Bianchi, Thomas S.; Chmura, Gail L.; Eyre, Bradley D.; Fourqurean, James W.; Hall-Spencer, Jason; Huxham, Mark; Hendriks, Iris; Krause-Jensen, Dorte; Laffoley, Dan; Luisetti, Tiziana; Marbà, Núria; Masque, Pere; McGlathery, Karen J.; Megonigal, J. Patrick; Murdiyarso, Daniel; Russell, Bayden D.; Santos, Rui; Serrano, Oscar; Silliman, Brian R.; Watanabe, Kenta; Duarte, Carlos M.The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the field to agree upon the top-ten pending questions in BC science. Understanding how climate change affects carbon accumulation in mature BC ecosystems and during their restoration was a high priority. Controversial questions included the role of carbonate and macroalgae in BC cycling, and the degree to which greenhouse gases are released following disturbance of BC ecosystems. Scientists seek improved precision of the extent of BC ecosystems; techniques to determine BC provenance; understanding of the factors that influence sequestration in BC ecosystems, with the corresponding value of BC; and the management actions that are effective in enhancing this value. Overall this overview provides a comprehensive road map for the coming decades on future research in BC science.
- The future of the northeast Atlantic benthic flora in a high CO2 worldPublication . Brodie, Juliet; Williamson, Christopher J.; Smale, Dan A.; Kamenos, Nicholas A.; Mieszkowska, Nova; Santos, Rui; Cunliffe, Michael; Steinke, Michael; Yesson, Christopher; Anderson, Kathryn M.; Asnaghi, Valentina; Brownlee, Colin; Burdett, Heidi L.; Burrows, Michael T.; Collins, Sinead; Donohue, Penelope J. C.; Harvey, Ben; Foggo, Andrew; Noisette, Fanny; Nunes, Joana; Ragazzola, Federica; Raven, John A.; Schmidt, Daniela N.; Suggett, David; Teichberg, Mirta; Hall-Spencer, JasonSeaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north. Seagrasses will proliferate, and associated epiphytes switch from calcified algae to diatoms and filamentous species. Invasive species will thrive in niches liberated by loss of native species and spread via exponential development of artificial marine structures. Combined impacts of seawater warming, ocean acidification, and increased storminess may replace structurally diverse seaweed canopies, with associated calcified and noncalcified flora, with simple habitats dominated by noncalcified, turf-forming seaweeds.