Without doubt, seagrass meadows play a vital role in our oceans. However, seagrass meadows are one of the most threatened habitats globally and also one of the most overlooked. These seemingly unsuspecting marine flowering plants play a crucial role in keeping our oceans healthy and providing habitat for a whole host of marine life.
Here we will learn more about these secret underwater forests and what we can do to help protect them into the future …
Creating Habitat For Other Important Species
Seagrass is capable of turning mud and sandflats into incredibly complex meadows. These underwater forests create an entire ecosystem that supports thousands of marine animals, such as more than 1000 species of fish. These underwater meadows also support endangered species like turtles and seahorses. They are also crucial nurseries for juvenile fish. In fact, it’s estimated that seagrass meadows support the productivity of around 20% of the world’s biggest fisheries! Finally, they also provide a safe place where species like cuttlefish and sharks can lay their eggs.
As well as providing habitat, they also provide a vital food source that is a key part of the food web and a particular favourite of dugongs, manatees and some turtles.
Improving Water Quality
Seagrass plays a role in chemical processes such as water purification. As marine plants, seagrasses photosynthesise, which helps oxygenate the water column. Seagrass meadows also stabilize sediment which improves water clarity, which also improves local water quality. By filtering the water column, seagrass removes seawater pollution. This includes removing fish pathogens, which helps keep local fish populations healthier, reduce contamination in seafood and reduce coral disease.
Seagrass Meadows Protect Our Coastlines
With rising sea levels, many coastlines are under threat from erosion. Healthy seagrass meadows reduce the power of waves hitting the coast and as some seagrass species have leaf blades up to 1m long, this can really help dampen wave action. Through reducing wave action this also protects coastlines from flooding and storms.
They are recognised as globally important habitats. Contributing significantly to human well-being and marine diversity because of the huge number of benefits healthy seagrass meadows can naturally provide us. Known as ecosystem services.
The Intergovernmental Panel on Climate Change estimates that through providing food and financial income from coastal fishing, coastal protection and their cultural significance, seagrasses support approximately three billion people. This makes seagrass meadows the third most valuable habitat in the world, after estuaries and wetlands. To put this in monetary terms, seagrass ecosystems contribute an estimated $1.9 trillion USD per year to the global economy.
Seagrass Even Traps Ocean Plastics
Recent research has found that these amazing meadows also play a role in trapping ocean plastics. Floating plastics, such as those seen in the Great Pacific Garbage Patch, are estimated to only make up 1% of global ocean plastic with the rest sinking to the seafloor. Seagrasses are able to trap these pieces of plastic within their natural fibres which eventually form small balls known as ‘neptune balls’. These plastic bundles are ejected from the meadow during storms and wash up on beaches. The study estimated that seagrass meadows in the Meditarrean alone can trap approximately 867 million pieces of plastic every single year.
Offsetting Climate Change
Seagrass is one of the most important species in the sea for locking in harmful carbon dioxide. The greenhouse gas known to significantly contribute to global warming. Amazingly, seagrass absorbs carbon dioxide from the atmosphere up to 40 times faster than tropical rainforests, which helps to offset climate change.
Seagrass meadows occupy less than 0.2% of the world’s oceans, yet they are responsible for more than 10% of all carbon buried annually in the oceans. The natural ability of seagrass to offset carbon dioxide emissions has hugely important implications for climate change mitigation.
Seagrass Meadows Are Under Threat
Seagrass meadows are in decline. Conservative estimates show that around 58% of seagrass meadows are in decline. The rate of seagrass loss is comparable to those being recorded for mangroves, coral reefs, and tropical rainforests. Making seagrass meadows among the most threatened ecosystems on earth. In a recent study, scientists estimated that we are currently losing a football field size area of seagrass every 30 minutes.
There are several reasons behind the widespread loss of seagrass meadows. Seagrasses are experiencing the five most serious threats to marine biodiversity; overexploitation, physical modification (such as the building of ports and harbours), nutrient and sediment pollution, introduction of non-native species and global climate change. Direct and immediate seagrass loss is caused by destructive fishing practices, coastal engineering and extreme weather events. More indirect and potentially more damaging are the impacts of declines in water quality.
Hopefully by now you have realised how amazing seagrass is (if you didn’t already know)! These vital underwater meadows do so much to protect us, lets help them out in return …
What Can You Do To Help Seagrass Meadows?
There are lots of incredible organisations actively fighting to conserve seagrass meadows around the world. Examples to check out include Project Seagrass, the Marine Conservation Society and the Ocean Conservation Trust.
Know of a local seagrass meadow near you? Help contribute to global maps to identity where seagrass meadows are using Seagrass Spotter. With just a few taps of your phone, you could help lead to new discoveries about seagrass whilst being part of the global community of ocean enthusiasts.
Advocate for Action
Campaign for changes to regulations or laws that help protect and conserve seagrass meadows, such as sewage pollution. Petitions are a great way of advocating for action.
There are lots of other activities you can do that will help seagrass meadows. Beach cleans and volunteering with your local wildlife organisation or charity and making more sustainable choices are all amazing ways to improve the health of our oceans and coastlines.
Read : 3 Great Reasons To Do Beach Cleanups and our other cleanup related blog for more
Education is key! Educating others helps raise awareness of the importance of seagrass meadows and encourages others to help protect and conserve seagrasses.
Katie Watson is a marine biologist, researching how to improve seagrass restoration in South Africa before this incredible ecosystem is lost. Go explore the underwater world with her on IG: @underwaterwithkatie to learn how surprising and diverse marine life really is!