Quantifying our
marine meadows – past, present.
A threadbare carpet.
Everyone knows their own science interests, the areas of research that they find thought-provoking. Sometimes I think that there are also subjects that we don’t realise we find fascinating. I never knew I was interested in seagrasses but this is the third sciku I’ve published about them, the second that I’ve written myself. It’s curious that I wouldn’t have known this about myself before today when this research paper caught my eye.
Seagrasses are hugely important ecosystems. In the sciku ‘Forgotten value’ I wrote about how seagrass meadows provide a nursery habitat for over a fifth of the world’s largest 25 fisheries. And as Dr Phil Colarusso showed with his sciku ‘Blue Carbon’, seagrass meadows collect and sequester large amounts of carbon, removing it from the global carbon cycle. As a result seagrass meadows are referred to as blue carbon habitats, along with salt marshes and mangroves.
Today’s sciku is based on a study by Green et al (2021), which examines the historical loss of seagrasses from the waters around the United Kingdom. By scrutinising multiple accounts from as early as 1831 and using data collected from 1900 onwards the researchers were able to estimate the UK’s seagrass losses. It makes for sobering reading:
“At least 44% of United Kingdom’s seagrasses have been lost since 1936, 39% since the 1980’s. However, losses over longer time spans may be as high as 92%.”
The research shows that the UK currently has only 8,493 hectares of seagrass meadows remaining. That’s approximated 0.9 Mt (million tonnes) of carbon, equivalent to around £22 million in the current carbon market. Whilst that may seem a lot, it’s worth considering that historic seagrass meadows could have stored 11.5 Mt of carbon, supporting around 400 million fish.
These losses are catastrophic but the information from this study can be used to inform future monitoring and restoration efforts. What’s more, by quantifying the benefits we gain from seagrass meadows as well as what we’ve lost from their disappearance, the findings also provide an impetus for improved conservation efforts, beyond ‘softer’ arguments such improving biodiversity.
Original research: https://doi.org/10.3389/fpls.2021.629962