Optimising Seagrass Density for Maximum Carbon Storage

Seagrass meadows are increasingly recognised as vital allies in the fight against climate change, acting as underwater warehouses for 'blue carbon'. While restoration programmes are expanding globally, a critical question has remained unanswered: exactly how dense should these underwater gardens be to maximise their ability to trap and store carbon? A recent study focusing on the tropical species Enhalus acoroides has finally provided some much-needed numbers.

The researchers discovered that simply packing in as many plants as possible is not necessarily the most efficient strategy. Instead, they identified a precise threshold for optimal performance. While survival rates were excellent across the board, exceeding 95 per cent, the ability of the seagrass to trap and bury particulate organic carbon—the biological material we want to lock away—peaked at a density of 113 to 118 shoots per square metre. Interestingly, the study found that trapping inorganic matter required slightly higher densities.

This research moves restoration efforts from guesswork to precision engineering. By adhering to these specific density targets, conservationists can significantly enhance sediment carbon stabilisation. This seemingly small adjustment offers a powerful tool for nations aiming to meet their contributions under the Paris Agreement, ensuring that every square metre of restored seabed acts as an efficient engine for cooling our warming planet.