BGS completes first mapping expedition to Ascension Island

On 30 October 2023, BGS project manager and senior surveyor Rhys Cooper and marine geoscientist Catriona Macdonald took the 4000-mile journey to Ascension Island, an isolated volcanic island in the Atlantic Ocean, to undertake the first stage of a UK Government-funded project.

In 2019, BGS was awarded funding from the UK Government through Darwin Initiative, a grant scheme by the Department for Environment, Food and Rural Affairs (Defra) that funds projects aiming to protect unique biodiversity and improve resilience to climate change within the UK Overseas Territories. Following a four-year delay due to COVID-19, the project is now underway. The first expedition focused on mapping the shallow waters surrounding Ascension Island, including an area of the island that has never been mapped or surveyed before.

Working with the Ascension Island Government, this BGS-led project will determine the character, distribution and extent of the nearshore habitats of the Ascension Island Marine Protected Area (AI-MPA) through an integrated programme of surveys. The AI-MPA is rich in biodiversity; however, protected areas such as this are most at risk from anthropogenic development and climate change.

Resulting sea-floor habitat maps will provide the Ascension Island Government with urgently needed tools to better monitor and protect marine ecosystems, as well as underpin the evidence-based management of the AI-MPA. The data will be merged with an existing dataset collected by the Royal Navy UK Hydrographic Office (UKHO) in 2021, which has already enabled the deployment of an array of sensors to monitor the movement of sharks. The combined datasets will also allow the first detailed geomorphology, substrate and habitat maps to be produced for the island, down to a maximum depth of 1000 m.

Ascension Island is a remote location and therefore presents many unique challenges that need to be overcome if we are to be successful. We have had numerous delays that proved fortuitous: the Royal Navy completed a survey around Ascension Island during COVID-19 lockdowns, which significantly reduced the amount of data we needed to collect, lowering costs and enabling us to refine and focus our survey campaigns.

The Ascension Island Government owns a boat that was made available to the project. This simplified logistics but required a totally different methodology for deploying the survey equipment. An appropriate solution was found and trialled in the UK before shipping the equipment to Ascension Island. This ‘warm-up’ survey allowed us to check it worked, was safe to operate and ensured we had all the equipment needed.

Rhys Cooper, project manager and senior surveyor.

Ascension Island expedition preparation in Port Edgar. BGS © UKRI

The team is set to return to Ascension Island in January 2024 to complete the next stage of the project, which will focus on seabed sampling. A high-definition drop camera with laser scaling will be deployed to enable accurate mapping of the sea floor. The project is expected to be completed in April 2024.

This project is funded by the UK Government through Darwin Plus.