William Ross Hunter 

Blue carbon is defined as carbon that is naturally sequestered and stored in the world’s aquatic ecosystems. Governments around the world are currently seeking to develop a range of tools to help meet their commitments to reduce greenhouse gas emissions and potentially reverse anthropogenic climate change. As such, there is growing interest from policy makers in natural processes which may be managed to maximise carbon sequestration. Northern Ireland is a constituent region of the United Kingdom that encompasses 14,330 km2 of land and 6000 km2 of shelf sea on the North easter portion of the island of Ireland. This review and evidence synthesis outlines the biogeochemical processes involved in carbon sequestration and storage in marine ecosystems and seeks to provide initial estimates of carbon sequestration and burial in Northern Ireland’s marine habitats. Overall Northern Ireland’s marine space encompasses 3812 km2 of shallow subtidal habitats, 1670 km2 of deep offshore habitats in the Irish Sea and 518 km2 of sea loughs. These habitats store between 14 and 22 Teragrams of Carbon, according to current estimates. However, there is considerable uncertainty regarding these estimates of Northern Ireland’s blue carbon stocks. As such, a detailed mapping exercise is needed to support the development of a regional blue carbon inventory. This is of particular importance, given that the deep offshore habitats in the Irish Sea which are estimated to support much of the regions carbon storage are heavily fished (primarily for Nephrops norvegicus). This evidence synthesis identifies uncertainty in the current scientific literature around impacts of fishing on seabed carbon storage. This highlights a clear need to obtain region-specific information on fishing impacts in the Irish Sea to support future policy development.