Review status: this preprint is currently under review for the journal BG.
Blue Carbon Stocks and Exchanges Along the Pacific West Coast
Melissa A. Ward1,2,Tessa M. Hill1,Chelsey Souza1,Tessa Filipczyk1,Aurora M. Ricart1,3,Sarah Merolla1,Lena R. Capece1,Brady C. O’Donnell1,Kristen Elsmore1,Walter C. Oechel2,and Kathryn M. Beheshti4Melissa A. Ward et al.Melissa A. Ward1,2,Tessa M. Hill1,Chelsey Souza1,Tessa Filipczyk1,Aurora M. Ricart1,3,Sarah Merolla1,Lena R. Capece1,Brady C. O’Donnell1,Kristen Elsmore1,Walter C. Oechel2,and Kathryn M. Beheshti4
Received: 05 Feb 2021 – Accepted for review: 12 Feb 2021 – Discussion started: 17 Feb 2021
Abstract. Salt marshes and seagrass meadows can sequester and store high quantities of organic carbon (OC) in their sediments relative to other marine and terrestrial habitats. Assessing carbon stocks, carbon sources, and the transfer of carbon between habitats within coastal seascapes are each integral in identifying the role of blue carbon habitats in coastal carbon cycling. Here, we quantified carbon stocks, sources, and exchanges in seagrass meadows, salt marshes, and unvegetated sediments in six bays along the Pacific coast of California. The salt marshes studied here contained approximately twice as much OC as did seagrass meadows, 23.51 ± 1.77 kg OC m−3 compared to 11.01 ± 1.18 kg OC m−3, respectively. Both seagrass and salt marsh sediment carbon stocks were higher than previous estimates from this region but lower than global and U.S.-wide averages, respectively. Seagrass-derived carbon was deposited annually into adjacent marshes during fall seagrass senescence. However, isotope mixing models estimate that negligible amounts of this seagrass material were ultimately buried in underlying sediment. Rather, the vast majority of OC in sediment across sites was likely derived from planktonic/benthic diatoms and C3 salt marsh plants.
Salt marshes and seagrass meadows (blue carbon habitats) can sequester and store high levels of organic carbon (OC) – helping to mitigate climate change. In California blue carbon sediments, we quantified OC storage and exchange between these habitats. We find that 1) these salt marshes store about twice as much OC as do seagrass meadows, and 2) while OC from seagrass meadows is deposited into neighboring salt marshes, little of this material is sequestered as long-term carbon.
Salt marshes and seagrass meadows (blue carbon habitats) can sequester and store high levels of...