The renaissance of Odum's outwelling hypothesis in 'Blue Carbon' science

• DOI: 10.1016/j.ecss.2021.107361
• Publication Date: 2021-04-04T00:02:38Z
• Authors: Isaac R. Santos; David J. Burdige; Tim C. Jennerjahn; Steven Bouillon; Alex Cabral; Oscar Serrano; Thomas Wernberg; Karen Filbee-Dexter; Julia A. Guimond; Joseph J. Tamborski
• Keywords: Carbon sequestration; 0106 biological sciences; Terrestrial and Aquatic Ecology; 550; Climate; Ecology and Evolutionary Biology; Alkalinity; MANGROVE TIDAL CREEK; Oceanography; 01 natural sciences; 7. Clean energy; 333; VEGETATED COASTAL HABITATS; 11. Sustainability; Physical Sciences and Mathematics; POREWATER EXCHANGE; Marine & Freshwater Biology; 14. Life underwater; INTERTIDAL SALT MARSHES; Science & Technology; Coastal carbon; CO2 EVASION; Life Sciences; Oceanography and Atmospheric Sciences and Meteorology; 15. Life on land; TURTLE GRASS; PORE WATERS; Detritus; 13. Climate action; DISSOLVED INORGANIC CARBON; Physical Sciences; Life Sciences & Biomedicine; PARTICULATE ORGANIC-MATTER; Environmental Sciences; DOMINATED ESTUARY

Este artículo contiene 11 páginas, 3 figuras, 1 tabla. The term ‘Blue Carbon’ was coined about a decade ago to highlight the important carbon sequestration capacity of coastal vegetated ecosystems. The term has paved the way for the development of programs and policies that preserve and restore these threatened coastal ecosystems for climate change mitigation. Blue carbon research has focused on quantifying carbon stocks and burial rates in sediments or accumulating as biomass. This focus on habitat-bound carbon led us to losing sight of the mobile blue carbon fraction. Oceans, the largest active reservoir of carbon, have become somewhat of a blind spot. Multiple recent investigations have revealed high outwelling (i.e., lateral fluxes or horizontal exports) of dissolved inorganic (DIC) and organic (DOC) carbon, as well as particulate organic carbon (POC) from blue carbon habitats. In this paper, we conceptualize outwelling in mangrove, saltmarsh, seagrass and macroalgae ecosystems, diagnose key challenges preventing robust quanti fication, and pave the way for future work integrating mobile carbon in the blue carbon framework. Outwelling in mangroves and saltmarshes is usually dominated by DIC (mostly as bicarbonate), while POC seems to be the major carbon species exported from seagrass meadows and macroalgae forests. Carbon outwelling science is still in its infancy, and estimates remain limited spatially and temporally. Nevertheless, the existing datasets imply that carbon outwelling followed by ocean storage is relevant and may exceed local sediment burial as a long-term (>centuries) blue carbon sequestration mechanism. If this proves correct as more data emerge, ignoring carbon outwelling may underestimate the perceived sequestration capacity of blue carbon ecosystems. Research on the topic was initiated with support from the Australian Research Council and concluded with funding from the Swedish Research Council to IRS. OS acknowledges financial support from Edith Cowan University. DJB acknowledges support from the US National Science Foundation (OCE 1635403). TCJ acknowledges support from the German Federal Ministry of Education and Research (03F0471A, 03F0644A). The graphical ab stract photo was provided by Luke Jeffrey. Peer reviewed