Seagrass: A Seabed Superhero

Have you ever heard of seagrass? This amazing plant provides an impressive list of environmental services – supplying vital habitat to wildlife and fisheries, protecting our shores from erosion and storing carbon up to 35 times faster than tropical rainforests. This #WorldSeagrassDay we take a closer look at its surprising superpowers.

Bring to mind the Solent and you may first think of sailboats, the Royal Navy, or its significance as a gateway for shipping and trade. But below the surface of this bustling waterway lies an equally busy world filled with wonders: the Solent’s internationally important seagrass meadows. Seagrass is the only marine flowering plant and supports rich biodiversity, including amazing species like seahorses, spider crabs and pipefish.  

An important asset for local fisheries, seagrass meadows provide nursery and foraging areas for species like black seabream and sea bass, the latter of which spend up to seven years growing in the Solent and its estuaries before joining the adult population. Cuttlefish also visit the area every spring and summer to breed, attaching their dark black eggs, known as sea grapes, to the long leaves of the plants. 

 Seagrass meadows are an incredibly important asset in the fight against climate change – absorbing carbon dioxide in huge quantities and locking it away in the muds and sands they grow upon. They are one of the most efficient carbon-storing habitats on Earth, performing better than tropical rainforests. In fact, despite only covering about 0.1% of the seabed, seagrass meadows are responsible for sequestering up to 18% of all oceanic carbon. 

If this wasn’t impressive enough, seagrass also improves water quality by absorbing excess nutrients from wastewater and provides natural coastal protection by dampening wave energy. A recent study has shown they may even help to remove plastic from our oceans, trapping small pieces of plastic litter in fibrous orbs, known as Neptune balls, which are later washed ashore.

What threats does seagrass face? 

This incredible plant is under threat from pollution, human activity and the effects of climate change. It has also historically been impacted by disease. In the 1930s, a slime mould, Labyrinthula zosterae, caused the widespread decimation and destruction of up to 95% of all known seagrass beds in the North Atlantic. 

There have been further outbreaks and the re-establishment of seagrass meadows has been hindered by other pressures such as reduced water quality and damaging human activity on the seabed. Fishing trawls and shellfish dredges can tear up the vulnerable network of roots from which the seagrass grows and, once damaged, recovery can be very weak, if it occurs at all.  

A snakelocks anemone on seagrass

Snakelocks anemone on seagrass © Tim Ferrero

What’s the future for this super-plant?    

There is some good news on the horizon for seagrass. Today, almost all of the Solent’s seagrass meadows lie within Marine Protected Areas (MPAs). The Solent’s MPAs consist of Special Protection Areas (SPA) for birds and Special Areas for Conservation (SAC) for habitats and species that were designated under the European Birds and Habitats Directives; and our four new Marine Conservation Zones (MCZs) that were designated between 2016-2019 under the UK Marine and Coastal Access Act.  

As a result of these protections, much of the Solent’s most sensitive habitats lie within a fisheries bylaw which has, since 2014, made it illegal to use damaging fishing dredges and bottom trawls inside seagrass meadows. Even the wasting disease appears to have lost some of its virulence. There is still more to be done to ensure the future of these fantastic habitats, but it is an exciting time as the prospects of better protection, natural regrowth and even restoration come closer to being realised.    


Take action for seagrass 

The species in our seas are truly amazing, but they need your help to stay that way. Visit Secrets of the Solent to find out how you can volunteer with us or make simple lifestyle changes that support our seas.