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How Seagrass Meadows Help Fight Climate Change

Christian Saravia



Seagrass meadows are underwater ecosystems found in shallow, salty, or brackish waters that stretch along coastlines all over the world, from the tropics to the Arctic Circle. They are formed by flowering plants, which create meadows that provide food and shelter for marine life. Most species of seagrass meadows have long, green, grass-like leaves and are often confused with seaweeds, but are actually more closely related to land-based flowering plants. They have roots, stems, and leaves, and they produce flowers and seeds. Today, there are around 72 different species that are part of four major groups, and some meadows are even large enough to be viewed from space. Most Seagrass meadows tend to be overlooked, but they play a crucial role in keeping the planet healthy. These ecosystems support marine biodiversity, stabilize sediments, and protect coastlines. Beyond their ecological value, seagrass meadows are emerging as powerful allies in the fight against climate change

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One remarkable feature of seagrass is its ability to trap and store carbon dioxide, which is a process known as carbon sequestration. Seagrass meadows can sequester carbon up to 35 times faster than tropical rainforests. This stored carbon, also known as blue carbon, gathers in the sediment underneath the plants and can remain there for thousands of years if undisturbed. Seagrass roots anchor and trap organic material, allowing these meadows to behave as underwater carbon sinks, where they pull CO2 from the atmosphere and store it safely out of reach. However, this process is dependent on water quality. EPA Scientist Genevieve Pelletier explains, “Seagrass is very sensitive to water quality, so simply planting seagrass without ensuring appropriate conditions will be counterproductive. But with appropriate water quality, expansion of seagrass beds can allow long-term carbon storage”. This makes them essential for reducing the impact of global warming. 


Seagrass meadows have been given the name “nurseries of the sea”. Their meadows offer food, shelter, and breeding grounds for a variety of marine life— from invertebrates to large fish, sea turtles, and manatees. Many commercially important species like cod, snapper, and shrimp begin their lives in seagrass beds, meaning these ecosystems are vital for global fisheries. 


Seagrass meadows also provide habitat to endangered and vulnerable species, like green sea turtles (Chelonia mydas) and dugongs (Dugong dugon), meaning they support biodiversity. Without seagrass meadows, many of these endangered and vulnerable species would have trouble finding protective cover and food sources. Seagrass ecosystem health is closely linked to marine life health, which makes their conservation essential for preserving ocean biodiversity. 


Seagrass meadows don’t just play a role in climate regulation and biodiversity, but they also protect coastlines. Their dense root systems help sediment on the ocean floor, which works to prevent erosion and reduces the resuspension of particles that can cloud water and harm marine life. This process helps maintain water clarity and creates a more hospitable environment for marine life. 


Seagrass meadows also act as natural buffers against storm surges and wave energy. They absorb the force of incoming waves and, by doing so, reduce the risk of coastal flooding and property damage during extreme weather events. In areas that are vulnerable to hurricanes and rising sea levels, the presence of seagrass can make a significant difference in protecting both ecosystems and human communities. 


Despite their ecological importance, seagrass meadows are rapidly declining. Globally, seagrass meadows are disappearing at a rate of about 7% per year due to human-driven threats. Nutrient pollution, typically caused by agricultural runoff and sewage, continues to be a pressing issue. It causes algal blooms that block sunlight from reaching the seagrass below. This is a concern for seagrass meadows because without sufficient light, the seagrass cannot photosynthesize, and it dies. 


Coastal development also poses a significant threat to seagrass meadows. Construction, dredging, and boat traffic can physically damage seagrass beds and stir up sediment that smothers them. Boat anchors and propellers can also tear through seagrass meadows, which can create scars that take years to recover, if at all.


Climate change itself adds additional stressors. Rising ocean temperatures can disrupt growth cycles, while stronger storms can uproot entire meadows. Ocean acidification and sea level rise can also reduce the resilience of these ecosystems over time. These stressors not only cause an ongoing decline in seagrass habitats worldwide but also jeopardize the marine life, climate benefits, and coastal protection that they provide. 


Due to the decline of seagrass meadows, conservation and restoration efforts have begun to gain traction throughout the globe. One approach is replanting seagrass shoots in damaged areas. This method has shown much promise, especially when combined with protections that limit boat traffic and reduce coastal pollution. Large-scale restoration projects in Virginia’s coastal bays have resulted in over 7,000 acres of seagrass returning to areas where it previously disappeared. Scientists are also exploring seagrasses as a natural climate solution, with research suggesting that these habitats can contribute to long-term climate mitigation through sediment carbon sequestration and can even help buffer against ocean acidification.


Public education and community involvement also help seagrass meadow conservation efforts. Citizen science initiatives spread awareness to local residents and allow them to partake in monitoring water quality, identifying threats, and assisting in planting efforts. These programs increase the success of restoration and also strengthen public support for marine conservation. Government policies and marine protected areas (MPAs) also help to preserve existing seagrass meadows. Designating certain zones as off-limits to activities that might be destructive helps to create environments where seagrass is able to recover and thrive naturally. Protecting seagrass meadows involves collaboration between scientists, governments, and the public. Continuing to spread awareness can help to revive damaged seagrass ecosystems.  


Seagrass meadows might not get as much attention as rainforests or coral reefs, but their role in maintaining a healthy environment is just as important. From capturing carbon to providing food and habitat for marine life to protecting coastlines, these ecosystems provide essential benefits for both humanity and the nature that surrounds us. With the threats of climate change and increasing coastal development, protecting seagrass meadows has become urgent. Supporting restoration projects, advocating for marine protections, and raising awareness are all ways that we can ensure that these underwater forests continue to thrive.




Citations

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