New Report Examines the Blue Carbon Potential of Norwegian Seagrass and Macroalgal Ecosystems
A new report by Mia Conti, developed in collaboration with C‑BLUES, has been published, examining the potential of two important Norwegian Blue Carbon Ecosystems (BCEs): seagrass meadows (Zostera marina) and macroalgal systems, including kelp forests and rockweed beds.
The work was carried out with Richard Bellerby serving as committee co-chair.
Assessing Blue Carbon Ecosystems in Norway
Blue carbon ecosystems are coastal vegetated habitats that can sequester and store carbon over long timescales. As interest in nature-based climate solutions grows, there is increasing attention on how these ecosystems can contribute to climate mitigation efforts and climate policy.
The report evaluates Norwegian seagrass and macroalgal ecosystems as potential candidates for blue carbon policy and broader marine nature-based solutions. The analysis combines carbon and ecosystem service databases, uncertainty analyses, spatial mapping approaches, and policy evaluation.
Key Findings
The study found that seagrass occupies a relatively small area in Norway, with a modelled extent of approximately 90 km². However, seagrass is directly compatible with sediment-based blue carbon accounting because carbon is stored in underlying sediments.
The report also found significant regional variation in sediment carbon density. Lower values were observed in the Barents Sea, while higher values were found in the Oslofjord and Skagerrak regions. These differences were linked to environmental factors such as sediment characteristics, hydrodynamic exposure, and water depth.
Macroalgal ecosystems were found to cover much larger areas along the Norwegian coast. The report estimates approximately 7,417 km² of kelp forests and 3,090 km² of rockweed beds. These ecosystems contain larger biomass-carbon pools and annual production fluxes than seagrass. However, because this carbon is stored in living biomass, its contribution to long-term carbon storage depends on export, deposition, and burial processes occurring outside the habitat itself.
Implications for Policy
The report notes that these differences have implications for policy development.
For seagrass, the findings indicate compatibility with the IPCC Wetlands Supplement and suggest that inventory approaches could be progressively improved as mapping, disturbance, and burial-rate data become more robust.
For macroalgae, the report identifies ongoing uncertainties related to carbon accounting and highlights the importance of further research on carbon export and storage pathways.
The report suggests that both ecosystem types should be protected and monitored and that they can play a role in climate and environmental policy as scientific understanding continues to develop.
A Collaborative Contribution
This report adds to the growing body of research on blue carbon ecosystems and their role in climate mitigation and coastal management.
C‑BLUES is pleased to have contributed to this work and congratulates Mia Conti on the publication of this report, as well as Richard Bellerby for his role as committee co-chair.
Read the report here.