CO2 leakage alters biogeochemical and ecological functions of submarine sands
Este artículo contiene 16 páginas, 5 figuras, 3 tablas. ; Subseabed CO2 storage is considered a future climate change mitigation technology. We investigated the ecological consequences of CO2 leakage for a marine benthic ecosystem. For the first time with a multidisciplinary integrated study, we tested hypotheses derived from a meta-analysis of previous experimental and in situ high-CO2 impact studies. For this, we compared ecological functions of naturally CO2-vented seafloor off the Mediterranean island Panarea (Tyrrhenian Sea, Italy) to those of nonvented sands, with a focus on biogeochemical processes and microbial and faunal community composition. High CO2 fluxes (up to 4 to 7 mol CO2 m−2 hour−1) dissolved all sedimentary carbonate, and comigration of silicate and iron led to local increases of microphytobenthos productivity (+450%) and standing stocks (+300%). Despite the higher food availability, faunal biomass (−80%) and trophic diversity were substantially lower compared to those at the reference site. Bacterial communities were also structurally and functionally affected, most notably in the composition of heterotrophs and microbial sulfate reduction rates (−90%). The observed ecological effects of CO2 leakage on submarine sands were reproduced with medium-term transplant experiments. This study assesses indicators of environmental impact by CO2 leakage and finds that community compositions and important ecological functions are permanently altered under high CO2. ; This work was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 265847 [Sub-seabed CO2 storage: Impact on Marine Ecosystems (ECO2)] and supported by the Max Planck Society and by the Flemish Fund for Scientific Research (grant number 1242114N). This study is also a contribution of D.M. to the research project MarSymBiomics (reference number CTM2013-43287-P), funded by the Spanish "Agencia Estatal de Investigación" (AEI), and PopCOmics (CTM2017-88080), funded by the AEI and the European Funds for Regional Development (FEDER) and to the Consolidated Research Group on Marine Benthic Ecology (2014SGR120) of the Generalitat de Catalunya. ; Peer reviewed
