A groundbreaking study has produced the most detailed map to date of predicted carbon stocks in Canada’s seafloor sediments. This map is crucial for future seabed management and climate mitigation policies. The map, created using a machine learning predictive mapping process, spans 4,489,235 km², covering 78.4% of Canada’s marine area.
Seafloor Carbon Significance
Globally, seafloor sediments store more carbon than all terrestrial soils. Despite this, coastal and terrestrial management plans often overshadow the seafloor’s role in mitigating climate change due to limited data. Recent efforts have focused on mapping this significant carbon reservoir to incorporate it into broader climate strategies.
Highlights:
- Predictive Mapping: A new high-resolution map integrates carbon considerations into national and regional seabed planning.
- Seabed Carbon Storage: Surficial seabed sediments along Canada’s continental margin hold an estimated 10.9 billion tonnes of organic carbon.
- Comparative Scale: This amount is about 100 times the carbon in all Canadian seagrass beds and saltmarshes, nearly half of the carbon in Canada’s forest vegetation, and 10% of the carbon in soils.
Key Findings
- Carbon Stock Estimates: The top 30 cm of sediment holds approximately 10.9 gigatonnes of organic carbon, with an uncertainty range of 7.0 to 16.0 gigatonnes.
- High-Density Areas: Small areas within nearshore zones, such as British Columbia’s inlets and fjords, parts of the Salish Sea, and enclosed nearshore regions of the Atlantic coast, exhibit the highest carbon density. Other significant areas include the Gulf of St Lawrence, the central Scotian Shelf, and offshore channels west of Vancouver Island.
Human Impact and Management
Human activities, notably global fishing, may cause the remineralization of seabed carbon stocks back to CO2. The new maps can guide research and management strategies to mitigate these impacts. Continuous improvements and additional data will enhance these maps, forming a basis for integrating climate considerations into seabed management.
Policy Implications
The new carbon sediment information will be instrumental in various marine planning initiatives in Canada. These include:
- Protected Area Management: Supporting conservation objectives for new and existing marine protected areas.
- Fisheries Management: Informing decisions on fisheries, especially those involving bottom trawling gear.
- Offshore Renewable Energy: Planning for sustainable offshore energy sites.
As Canada develops its ocean and climate policies, this research provides critical insights to inform decision-making processes. Integrating carbon considerations into marine planning will help mitigate environmental climate change impacts and preserve essential marine ecosystems.