Enhancing Blue Carbon Conservation: The Role of Muddy Seabed Sediments in Climate Mitigation and Marine Protected Areas

Muddy seabed sediments are increasingly recognized for their significant blue carbon value and potential in climate change mitigation. Estimated to store nearly twice as much organic carbon as terrestrial soils within the top meter, marine sediments account for approximately 75% of total ocean carbon burial. Despite their critical role in the carbon cycle and other important ecosystem services, these soft sediment habitats have been largely overlooked in the establishment of marine protected area (MPA) networks.  

The capacity of seabed sediments to sequester carbon is intricately linked to the ecological communities inhabiting them, driven by processes such as sedimentation, organic matter trapping, bio-irrigation, and bioturbation. However, these carbon-rich ecosystems are threatened by bottom-disturbing activities like trawling and dredging. These activities disrupt infaunal and epifaunal communities crucial for carbon storage as well as directly releasing organic carbon through resuspension and re-mineralization. 

As part of the Convex Seascape Survey, a transdisciplinary 5-year, multi-partner international project, we aim to understand how continental shelves store carbon and how past and present human activities have impacted these critical carbon reservoirs. In this study, we present new findings from multiple locations globally where we assessed the distribution of organic carbon, alongside infaunal, epifaunal, and fish communities across a gradient of protection from trawling and dredging. Our research integrates blue carbon assessments with marine biodiversity observations and monitoring, contributing to a still relatively novel approach to marine spatial planning and management.  

The Convex Seascape Survey underscores the need for climate-smart, area-based management approaches that integrate the blue carbon potential of soft sediment habitats into the design of MPA networks. By prioritizing the protection and restoration of these often-overlooked ecosystems, our findings provide evidence-based strategies to support the global “30 by 30” target, which aims to protect 30% of the Earth’s marine and coastal areas by 2030. These insights are crucial for enhancing the resilience of marine ecosystems, optimizing their role in climate mitigation, and promoting sustainable and equitable management practices.