Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DQ, UK
Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.
Biol Lett. 2018 Oct 3;14(10):20180336. doi: 10.1098/rsbl.2018.0336.
Blue carbon did not originally include macroalgal ecosystems; however evidence is mounting that macroalgal ecosystems function in marine carbon sequestration. The great majority of present day marine macroalgal net primary productivity (NPP) involves haptophytic algae on eroding shores. For these organisms the long-term storage of particulate organic carbon involves export from the site of production of biomass that has evaded parasites and grazers, and that some of the exported biomass is sedimented and stored rather than being mineralized by detritivores (microbes and fauna). Export from eroding shores, and subsequent storage, of haptophytic marine macroalgal particulate organic carbon could have started by 1.6 Ga. Storage on depositing shores close to the site of NPP by rhizophytic macroalgae and then by rhizophytic coastal seagrasses, tidal marshes and mangroves began not less than 209 Ma ago. Future increases in surface ocean temperatures may bring tropical marine macroalgae to their upper temperature limit, while temperate marine macroalgae will migrate poleward, in both cases assuming that temperature increases faster than genetic adaptation to higher temperature. Increased CO in the surface ocean will generally favour uncalcified over calcified marine macroalgae. This results in decreased CO release from decreased calcification, as well as decreased ballasting by CaCO of exported particulate organic carbon resulting in decreasing sedimentation. While much more work is needed, the available information suggests that macroalgae play a significant role in marine organic carbon storage.
蓝碳原本并不包括大型藻类生态系统；然而，越来越多的证据表明，大型藻类生态系统在海洋碳固存中发挥作用。当今海洋大型藻类净初级生产力（NPP）的绝大多数涉及到侵蚀海岸上的黄藻。对于这些生物来说，颗粒有机碳的长期储存涉及到从生物量生产地的出口，这些生物量逃脱了寄生虫和食草动物的侵害，而且一些出口的生物量被沉积和储存，而不是被碎屑动物（微生物和动物）矿化。黄藻等侵蚀海岸上的海洋大型藻类颗粒有机碳的出口和随后的储存可能早在 16 亿年前就开始了。然后，由根生大型藻类以及根生沿海海草、潮汐沼泽和红树林在靠近 NPP 地点的沉积海岸上进行的储存，开始于不少于 2.09 亿年前。未来海洋表面温度的升高可能会使热带海洋大型藻类达到其最高温度限制，而温带海洋大型藻类将向极地迁移，在这两种情况下，假设温度的升高速度快于对更高温度的遗传适应。海洋表面 CO2 的增加通常有利于无钙化的海洋大型藻类，而不利于钙化的海洋大型藻类。这导致由于钙化减少而减少 CO2 的释放，以及由于 CaCO3 对出口颗粒有机碳的加重作用减少而导致沉积减少。虽然还需要做更多的工作，但现有信息表明，藻类在海洋有机碳储存中发挥着重要作用。
