Blue Carbon
Wrasse and kelp forest Holywell. Photo credit Matt Slater, Cornwall Wildlife Trust
Cornwall Council is exploring the potential of blue carbon in Cornwall's coastal waters. Blue carbon is a term used to describe the carbon captured by the world’s oceans and coastal habitats and is a vital tool in stabilising climate change. Cornwall’s blue carbon ecosystems include seagrass, mud flats, salt marsh, maerl (an ancient coral reef) and kelp.
Blue Natural Capital Project
In January 2024, Cornwall Council completed their Blue Natural Capital Project.
The Project, funded by the Natural Environment Investment Readiness Fund (NEIRF) has expanded previously limited knowledge in Cornwall to provide a clearer understanding of blue carbon habitat extent and health, and created a baseline of evidence to inform options to unlock future private funding for natural capital in the county and beyond.
Through collaborative work with our partners, the Project has resulted in;
Baselining: Undertaken surveys and analysis to understand the amount of carbon stored within kelp, maerl, saltmarsh and seagrass in two important Cornish coastal locations - Fal and Helford Estuary, and Mounts Bay.
Modelling: Modelled the potential for recovery of these blue carbon habitats, plus completed Natural Capital and ecosystem service risk assessments, at the two key sites.
Investing: Informed the development of options for increasing investment in the marine environment in Cornwall using the knowledge created through the results of the baseline and modelling research.
Research highlights;
The Fal and Helford supports an astounding 880 hectares of maerl, indicating it as a key UK site for this irreplaceable blue carbon habitat. The maerl found in the Fal Estuary was also rich in organic carbon, supporting the thought that maerl beds have the potential to store large quantities of blue carbon for centuries to millennia.
A new seagrass bed was discovered in Mounts Bay covering 290 hectares and spanning 5km.
A substantial amount of saltmarsh, at 26 hectares, exists outside of the Fal and Helford Special Area of Conservation (SAC) boundary. This needs protection for its combined blue carbon value and future pressure from predicted sea level rise.
Excess nutrient discharge, recreational boating and increased turbidity scored as the greatest risks to impact the future health and functioning of these habitats in Cornwall.
The estimated total carbon taken up by the Maerl habitats across the Fal & Helford Estuaries SAC is 266 tCO2e annually equivalent to approximately 700,000 car miles. This has a present value of £2.39 million over 50 years. This uptake of carbon by maerl is higher than the other blue carbon habitats studied, even seagrass.
Although setting up a formal biodiversity or ecosystem service credit scheme in Cornwall in the immediate future may not be possible due to the need for further science, it is still possible to gain investment in projects now through pathways such as philanthropic investment.
Diver over maerl bed at Pendennis Point. Photo credit Matt Slater Cornwall Wildlife Trust
The information created by the Project will help;
Direct the next stages of blue carbon research, such as considering whole ecosystem carbon values (rather than just individual habitats) due to the complex cycling of carbon in the marine environment.
Support the development of national blue carbon policy and processes, such as emerging Blue Carbon Codes and Marine Net Gain.
Inform options for private investment in our marine environment via initiatives like Local Investment in Nature - Cornwall (LINC) which will support natural capital projects to engage with funders such as developer and businesses.
Guide new local projects to restore and increase areas of blue carbon habitats, such as no anchor zones.
The final reports from this project are now available to download to the right of this page.
Taken from project information leaflet available to download via the links on this page.
Seagrass
Seagrass bed with pollack. Photo credit Matt Slater Cornwall Wildlife Trust
Over recent years, Cornwall Council have commissioned projects to investigate seagrass to understand its true potential to help tackle the climate and ecological emergencies. Seagrass is a flowering plant that only grows in seawater and thrives as brilliant underwater meadows of green grass. Seagrass meadows are a natural solution to a range of issues: they clean our coastal waters and help to keep our ocean healthy and climate stable. Seagrass also provides a home and nursery for hundreds of species, including commercial fish, helping support the livelihoods of many Cornish residents. Seagrass is critically important for the long-term capture and storage of coastal blue carbon, and globally seagrass stores an estimated 10-18% of all ocean carbon.
Mapping of Mount’s Bay seagrass beds by Cornwall Council uncovered a revelation no one could have predicted. Surveys revealed a new area the size of 290 rugby pitches: it is one of the largest beds ever found in the UK. The bed is larger than all known seagrass beds in Cornwall combined and equates to 3.4% of known seagrass areas within the UK. These findings have reignited interest across Cornwall for the potential discovery of new seagrass beds using echo-sound technology.
A study by the University of Exeter found a total area of 172 rugby pitches of seagrass in the Fal & Helford estuaries: one of the most healthy and productive seagrass beds in the UK - this will aid Cornwall in its ambitions to become carbon neutral by 2030.
While exciting new discoveries are promising, these seagrass beds face many risks, also highlighted by this research. The main risks link to water quality, boating activities and climate change. The authorities in the Fal and Helford are working hard to reduce the pressures on seagrass beds and boat owners can help by following best practice and thinking carefully about where they anchor.
Seagrass Questions
Please feel free to ask any questions about Cornwall's Seagrass and our research into marine carbon storage.
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