Seagrass meadows – carbon sinks and fishery powerhouses

The most underappreciated of marine ecosystems, the humble seagrass meadow.

I might be biased, but seagrass meadows are just a little bit fantastic. Seagrasses are admirable in that they do a lot just by being themselves; they are the strong silent type, happy for their flashy coastal colleagues the coral reefs to get all the adoration, whilst they quietly continue in the background, churning out the next generation of baby fish, and sinking lethal dissolved carbon into the seabed. 

To borrow a rugby analogy, they are the second rows of the coastal seascape, working hard in the ‘engine room’ whilst it’s the ‘pretty’, ‘flashy’ backs that grab the headlines with their razzle-dazzle. Seagrass meadows are barely recognised on the world stage, and hardly ever make the front page news, but they are essential to our metaphorical team’s success, week in, week out.

Seagrass meadows provide carbon capture storage at rates up to 100 times greater than rainforests. One hectare (10,000 m2) of seagrass can support up to 80,000 fish, and produce up to 100,000 litres of oxygen per day. Put another way, in a recent Plymouth University study, seagrass meadows in the Mediterranean Sea were valued as contributing approximately €190 million per year to local fisheries.

The drawback for seagrass meadows is that they just aren't seen to be as sexy as coral reefs. However, with the passionate work of a handful of individuals we are looking to change that perspective. For example, here in the UK there are a couple of recently formed organisations championing the cause for seagrass meadows.

In the southwest of England there is a fantastic new venture called the ‘Community Seagrass Initiative’ being run out of the National Aquarium ( in Plymouth. Their CSI project covers the 191 mile stretch of coastline from Looe in Cornwall, to Weymouth in Dorset and is seeking to engage coastal communities with their local seagrass meadows, raising awareness and promoting conservation.

In Cardiff, Wales, one of the UK’s newest marine charities has also recently been born – Project Seagrass (, of which I am a proud founding member.

Project Seagrass is an environmental charity devoted to the conservation of seagrass ecosystems through education, influence, research and action. We’re here to communicate to you that seagrasses both locally and globally are under threat, and as such their capacity to act as both carbon sinks and fisheries powerhouses is being jeopardized by our actions.

So what are these threats? Anchoring and inappropriate moorings scar the seabed and uproot the seagrass; less seagrass equals fewer fish. Furthermore, coastal development, litter, pollution and waste can smother seagrasses reducing their access to the vital sunlight they need for growth; less seagrass growth equals less CO2 absorption.

Protecting seagrass helps to ensure food security and fights climate change. Some of our most iconic sea creatures live in seagrass; seahorses, sea turtles and sea cows all need seagrass meadows. Can you imagine a world without them?

Richard ‘RJ’ Lilley is a British seagrass scientist and science communicator. Follow Richard @rjlilley on Twitter. You can see more images of seagrass and learn more about his work by following @projectseagrass on Facebook, Twitter and Instagram.