Seabeds and wetlands vital for carbon capture - good data is essential

19/09/2024

Ocean habitats play a key role in storing carbon from the atmosphere. It's called 'blue carbon', and until now, nobody has quantified how much ends up in kelp, seagrass meadows, salt marshes and sediment in the seabed. Good quality baseline and longitudinal data is vital to assess and control the damage caused by human activities to the most carbon-rich ecosystems in the ocean, and to show where marine protected areas are required.

Undamaged marine habitats absorb carbon so it's not released into the atmosphere. A new study by scientists at the Scottish Association for Marine Science, reported in The Conversation's Imagine newsletter,  shows that 244 million tonnes of organic carbon are stored in just the top 10cm of seabed habitats around the UK. These habitats could capture three times as much carbon as UK forests do per year.

Kelp and seagrasses break off in the shallows, get carried offshore and sink, so carbon is absorbed into the sediment. So does dead plankton. Antarctic krill contribute twenty million tonnes of carbon annually from their faeces and other waste. Saltwater prevents the stored organic carbon from being converted back to CO₂ through remineralisation.

Krill contribute blue carbon equivalent to that of the world's mangroves, salt marshes and seagrass beds combined. Baseline data and ongoing mapping is essential so that any decline of blue carbon be properly monitored.

NOFF adds that Antarctic krill are threatened by unregulated industrial overfishing most of which goes into the production of farmed salmon feed, and that the recent but very overdue Tasmanian State of the Environment report identifies the poor state of Tasmania's quantification of virtually all aspects of its environment, including coastal areas and wetlands.