Blue carbon and nitrogen sequestration capacity of restored zostera marina meadows in the Arrábida Natural Park

• Autor(a) principal: Herrero Fernández, Ángela
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/19832
• topic: Blue carbon; Nitrogen; Seagrass; Restoration; Carbon sequestration

Seagrass meadows are coastal ecosystems situated almost throughout all of the world’s coastlines. They provide important ecosystem services such as coastal protection, nutrient cycling, pathogen reduction and provision of nursery grounds, among others. They share the ability of mangroves and tidal salt marshes to sequester carbon from the atmosphere and water column and to store it into their biomass and into the soil. Moreover, seagrasses enhance nitrogen burial within the sediment, creating a natural filter that improves water quality. Despite the benefits that seagrass meadows provide to human well-being, they are experiencing a global decline due to coastal development and increased water pollution, among other threats. Restoration of seagrass meadows can be a global feasible strategy to mitigate climate change by restoring their role as carbon and nitrogen sinks, compensating anthropogenic CO2 emissions and excessive nitrogen loads, while preserving these important ecosystems. However, information about the effectiveness of these projects on C and N sequestration service recovery is still needed. This study analyzed sediment biogeochemistry and sedimentary organic carbon (OC) and total nitrogen (TN) stocks within natural and open coast restored Zostera marina meadows in the Portuguese coast. The comparison between sites revealed that the amount of OC and TN deposited in the sediment, slightly increased through time although differences between natural and restored sedimentary stocks were not significant. Higher mud percentage was found within the superficial sediment layers of natural meadows pointing out that the simpler structure and higher hydrodynamics conditions of restored meadows, influence deposition of fine sediment. Further research will analyze the causes of variability and establish accurate sediment accretion rates, leading to a more complete evaluation of the restored seagrass meadows in recovering their ecological function as carbon and nitrogen sinks.