Saltmarshes are carbon-rich ecosystems that play a role in climate regulation by efficiently sequestrating atmospheric CO_(2).Climate change is a major threat to saltmarshes and will impact saltmarsh carbon sequestrat...Saltmarshes are carbon-rich ecosystems that play a role in climate regulation by efficiently sequestrating atmospheric CO_(2).Climate change is a major threat to saltmarshes and will impact saltmarsh carbon sequestration.Notably,porewater-derived carbon outwelling emerges as a crucial pathway for carbon sequestration,but it has been largely overlooked in saltmarshes.Here,we assessed the drivers of dissolved carbon exports and greenhouse gas emissions in a saltmarsh and placed those observations into a global context.In our study site,porewater exchange(PEX)was the major process controlling dissolved carbon and greenhouse gas dynamics.Combining our results with 33 other studies in saltmarshes worldwide,porewater-derived carbon fluxes were equivalent to~48% of average global saltmarsh primary productivity and 2.2 times greater than global organic carbon burial.Hence,our local observations and global upscaling demonstrate the major role played by PEX in saltmarsh carbon budgets.While part of dissolved inorganic carbon returns to the atmosphere as CO_(2),the remaining bicarbonate fraction is stored in the ocean over long time scales.Our findings strengthen global blue carbon assessments and build arguments for the use of saltmarshes as nature-based solutions for global climate change.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42006152)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21D060005)funding from the Swedish Research Council(Grant No.2020-00457)。
文摘Saltmarshes are carbon-rich ecosystems that play a role in climate regulation by efficiently sequestrating atmospheric CO_(2).Climate change is a major threat to saltmarshes and will impact saltmarsh carbon sequestration.Notably,porewater-derived carbon outwelling emerges as a crucial pathway for carbon sequestration,but it has been largely overlooked in saltmarshes.Here,we assessed the drivers of dissolved carbon exports and greenhouse gas emissions in a saltmarsh and placed those observations into a global context.In our study site,porewater exchange(PEX)was the major process controlling dissolved carbon and greenhouse gas dynamics.Combining our results with 33 other studies in saltmarshes worldwide,porewater-derived carbon fluxes were equivalent to~48% of average global saltmarsh primary productivity and 2.2 times greater than global organic carbon burial.Hence,our local observations and global upscaling demonstrate the major role played by PEX in saltmarsh carbon budgets.While part of dissolved inorganic carbon returns to the atmosphere as CO_(2),the remaining bicarbonate fraction is stored in the ocean over long time scales.Our findings strengthen global blue carbon assessments and build arguments for the use of saltmarshes as nature-based solutions for global climate change.
