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  • Fiona Beaty

Seagrasses are friends, not foes

Updated: Mar 8



Your arms cut through the glassy water as you swim toward the rocky islet. At the surface level, you watch little bugs daringly dancing as they snack upon tasty plankton and flirt with the danger of predators that might lurk below the surface. Your mind drifts off into a calm state. Suddenly you feel something twist around your ankle! It quickly snakes around your leg as you thrash against its grip – you panic completely.


This shock and fear seem to be many people’s main association with seagrass: the sneaky underwater plant that tickles our toes and scares us as we swim through shallow waters. But there are so many reasons to push back against this paranoia.

Super seagrass, picture modified from www.educationalvisitsuk.com

These plants deserve our respect and awe. They are an incredibly important part of coastal ecosystems and cultures, and are emerging as one of the most popular “nature-based solutions” to many of the problems that humans cause in our world. You name it, and seagrasses are stepping up to the plate to protect ocean health.


To begin with: the biodiversity crisis. Fish and invertebrate stocks are declining throughout the world largely due to destructive fishing practices. How do seagrasses combat this? Through the generous provision of safe home and habitat. Like coral reefs, seagrasses provide a home to millions of creatures who rely heavily upon the lush meadows for food and safety. Seagrasses also create some of the highest quality nursery habitat for young fish and invertebrates, such as Pacific salmon as they transition from their freshwater baby-stages to their marine adult bodies.

Approximately 400 species of marine life are found in eelgrass beds in the Salish Sea. Graphic provided courtesy of Ocean Wise: www.habitatprotection.ca

What about climate change? Where do I begin!? Here is where seagrasses show off their flashy and multifaceted personality. They trap and store carbon in their root systems (this underwater carbon storage is called ‘blue carbon’). Also, because they photosynthesize (breath in carbon dioxide and breath out oxygen), they can protect vulnerable invertebrates that live on their blades from the corrosive effects of ocean acidification (see here for an article on how seagrass can buffer their local environment).

Seagrass blades can catch microplastics when leaves slough off each season, and carry them to shore. Graphic from https://www.nature.com/articles/s41598-020-79370-3

Ok, well pollution has to be where seagrass fall flat, right? There’s no way that a plant can play a role in removing plastics from the ocean. Incredibly, recent research found that seagrass can, in fact, trap nefarious microplastics (small plastic fragments in the water) and facilitate their movement out of the ocean and onto the beach.


It’s pretty clear that seagrasses deserve our awe and gratitude. Importantly, like many creatures, they have a limit to how much protection they can provide. So, we need to act together with these magical marine plants. To stop habitat fragmentation, we can advocate for the protection (and restoration) of coastal habitats through local policy and management plans (see here for ideas). Slowing down ocean warming and acidification requires our societies to rapidly mitigate carbon emissions. And finally, the removal of microplastics must be accompanied by a swift reduction of plastics and pollution that enter the ocean and a transition toward a circular economy.


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