Seagrass of Seychelles' EEZ captures nearly same amount of CO2 as local energy emissions

Assessment at St. Joseph atoll. (H. Grimmel, Save Our Seas Foundation)

(Seychelles News Agency) - Results from an extensive seagrass distribution assessment undertaken within Seychelles' Exclusive Economic Zone (EEZ) by researchers indicate that these seagrass ecosystems are storing carbon dioxide (CO2) at a rate of 510,000 tonnes of CO2 equivalent per year.

According to a joint press release from the Seychelles Conservation and Climate Adaptation Trust (SeyCCAT) and the Ministry of Agriculture, Environment and Climate Change, this is nearly the same as the annual emissions from the local energy sector and almost three times the emissions from the transport sector.

Dr Gwilym Rowlands, an Earth Observation Scientist at Oxford, led the research in partnership with several local and international organisations and the German Aerospace Agency (DLR).

Using satellite imagery and meticulous ground surveys, the research team mapped 1,599 square kilometres of seagrass across the EEZ of 1.4 million square kilometres. The vast area, equivalent to 29,000 football fields, was identified as a significant resource capable of storing 18.9 million tonnes of organic carbon, amounting to 69 million tonnes of CO2.

The research project, titled "Seychelles Seagrass Mapping and Carbon Assessment Project", was initiated in 2020. It aligns with the government's commitment to safeguard 50 percent of its blue carbon ecosystems, including mangroves and seagrass meadows, by 2025 and achieve 100 percent protection by 2030.

Researchers at the D'Arros Atoll. (H. Grimmel, Save Our Seas Foundation) Photo License: All Rights Reserved

Seychelles, an archipelago in the western Indian Ocean, made a commitment at the 27th Conference of the Parties (COP27) in Sharm El-Sheikh, Egypt, to move to 100 percent protection of all its mangroves and seagrass meadows.

The commitment was made as a Nationally Determined Contribution (NDC) under the Paris Agreement with the goal of including these seagrass ecosystems within the Seychelles' National Green House Gas Inventory (NGGI).

In supporting the country's target, the project was designed to identify the distribution and extent of seagrass habitats in Seychelles' EEZ and this would then allow the quantification of the amount and rate at which these habitats store carbon.

According to the press release, "Further findings indicated that most seagrass habitats in Seychelles waters are around the Mahe Plateau Rim and the Amirantes Bank, with these areas inhabiting 32.9 percent and 30.3 percent of Seychelles seagrass, respectively."

While looking at the distribution of seagrass within the Seychelles Marine Spatial Plan (SMSP), the researchers were able to identify that 99.5 percent of Seychelles seagrass habitats are luckily found within High Biodiversity Zones and Medium Biodiversity and Sustainable Use Zones as well as pre-SMSP protected areas.

They however raised the concern that the most diverse seagrass meadows around Praslin and the Au Cap region, where at least seven species have been recorded, are located unfortunately within multiple-use zones. This, therefore, does not occur within an existing protected area.

The extensive study, which included the work of 50 predominantly Seychellois researchers and spanned over 20 institutions, has now quantified the importance of seagrass as a blue carbon ecosystem for Seychelles. It, therefore, provides the robust science needed to inform policy decisions regarding seagrass protection in Seychelles.