Last week marked the first official World Seagrass Day! As of 2023, the 1st of March is now formally recognised by the United Nations as World Seagrass Day, in order to highlight the importance of these marine habitats.
“The seagrass ecosystem is a perfect example of nature in action, where habitats and the delicate web of life are intertwined in perfect harmony. On this, International Seagrass Day, let us shine a light on the magic of seagrass meadows and the species, human and non-human alike, who depend on them.” (Leticia Carvalho, Head of the Marine and Freshwater Branch of the United Nations Environment Programme)
Seagrass grows in shallow ocean waters and marine estuaries and is reported to occur in 191 countries in both temperate and tropical regions. There is growing recognition of the role that seagrasses play as a carbon sink and their potential to act as a nature-based solution for climate change. Seagrass meadows can store up to twice as much carbon per hectare as terrestrial forests, however, unlike terrestrial forests where carbon stores are found within the trees themselves, the carbon stores of coastal ecosystems are mostly found within the sediment and soil. Currently, seagrass is still relatively under researched, especially in regions such as Southeast Asia, therefore the carbon storage potential in some locations may be under appreciated.
Alongside carbon storage, seagrasses support high levels of biodiversity and provide vital habits to species such as manatees and turtles, provide coastal protection from erosion and flooding, and support some of the world’s largest fisheries making them a critical source of food and livelihood. Their ability to buffer ocean acidification contributes to the resilience of other vulnerable ecosystems such as coral reefs.
Despite their benefits, seagrass meadows are experiencing degradation at an accelerating rate due to the impacts of climate change and anthropogenic activities. Major anthropogenic threats include sewage and agricultural sediment run-off, aquaculture, coastal development and mechanical damage. Unfortunately, recent research estimates that seagrass habitats are being lost at a rate of 7% worldwide per year. The UK itself is predicted to have lost as much as 92% of its historical seagrass populations. 21% of seagrass species are categorised as near threatened, vulnerable or endangered on the IUCN red list.
The conservation and restoration of seagrass meadows could help countries achieve 10 of the Sustainable Development Goals. Funding for these marine ecosystems needs to be rapidly ramped up in order to ensure the future provision of their benefits and services. Therefore, it is critical that these habitats are celebrated on World Seagrass Day, and their importance is widely recognised.