Seagrass – no, we’re not talking about the stuff you might find in your backyard or on a golf course. This seagrass lives underwater, swaying with the ocean currents in sandy shallows and brightly lit meadows. Seagrass may not get the same attention as its showy neighbor, the coral reef, but these underwater plants are just as critical for ocean health.
So what’s all the fuss about seagrass? Why should we care about a plant that looks like wet grass? Well, home gardeners know how awesome grass is – it’s soft, cool, and makes everything look tidier. Underwater grass is even more amazing. Seagrass meadows give Nemo a nursery, feed the turtles, and help save the planet. Keep reading to discover why seagrass deserves more appreciation and protection.
Importance for Ocean Wildlife
For many fish and marine creatures, seagrass meadows are the neighborhood they call home. Schools of fish swarm through the blades, crabs scuttle across the seafloor, and anemones wave their tentacles from rocky patches. Seagrass shelters, feeds, and protects diverse wildlife.
Safe Spaces for Fish
Fish flock to seagrass nurseries to spawn and take shelter. The meadows teem with larval and juvenile fish too tiny to survive in the open ocean. Minnows and wrasses weave through the vegetation while predator fish like barracudas peer out from dense patches. Pipefish clutch onto the blades, perfectly camouflaged in their thin vertical stripes. Seagrass traps nutrients and debris for fish to snack on. At high tide, large fish like snapper and grouper come hunting through the meadows for their next meal.
No wonder seagrass meadows contain up to 100 times more fish than bare sandy seafloor!
Home Sweet Home for Shellfish
Fun fact: did you know that seagrasses are hiding places for many crabs’ naughty bits? Male crabs will often cling onto a seagrass shoot using one claw to safely store their reproductive organs. Talk about a crazy dating strategy! Female crabs lurk in the seagrass too, waiting for a suitor.
Seagrass also houses shellfish including oysters, scallops, mussels and clams. They attach themselves to the leaves or settle into the sediment. Shrimp burrow into the sand beneath the seagrass canopy. Without seagrass, many shellfish species would lose their shelter and breeding grounds.
Hangout for Seahorses and More
From seahorses gripping the blades with their curly tails, to slippery sea cucumbers shuffling through the mud – seagrass harbors a wild range of underwater creatures. Sponges, jellyfish, sea stars, and anemones all thrive in seagrass ecosystems. The plants offer surfaces for invertebrates to cling to, while the mesh of rhizomes anchors the sediment.
Some species like weedy sea dragons and pipefish are masters of camouflage in seagrass. They sway back and forth mimicking the plants perfectly. Predators swim right by without noticing them! Seagrass meadows are definitely the most chill hangout spots for ocean oddities.
Feeding Grounds for Turtles and Manatees
For gentle herbivores like dugongs, manatees, and green sea turtles, seagrass meadows are an underwater salad bar. Munching on seagrass is like grazing on land. These endangered species rely on seagrass for their diets and are specially adapted to this food source.
Turtles Can’t Resist Seagrass
Green sea turtles use their sharp beaks to nibble on seagrass blades. They’ll even ferment seagrass in their gut to extract more nutrients from the fibrous plants! Seagrass meadows are the perfect feeding grounds for these ancient reptiles. Turtles graze peacefully on the undulating meadows close to shore.
In the Caribbean, threatened green sea turtles rely on turtlegrass beds. And in the Indo-Pacific, hawksbill sea turtles chow down on tropical seagrass species. Protecting seagrass ecosystems gives sea turtles safe dining areas. After all, you don’t want to keep a turtle from its lettuce!
Manatees Munch Below the Surface
Manatees are another famous fan of seagrass. These gentle “sea cows” spend 6-8 hours a day grazing on seagrass. Using their flippers to walk along the seafloor, manatees eat up to 10% of their massive body weight in plants each day! With no natural predators, a manatee’s biggest threat is angry, hungry stomach pangs.
Manatees living along the Atlantic coast and Caribbean rely on lush seagrass for their bulk. In Florida, scars from boat propellers mark many manatees – an unfortunate consequence of feeding in shallow seagrass areas. Protecting seagrass meadows near shore helps manatees safely access the succulent plants they depend on.
Dugongs Do Damage to Seagrass
The closely related dugong is another blubbery marine mammal sustained by seagrass. These shy herbivores live in coastal waters from East Africa to the Philippines. With their paddle-like tails and small flukes on the upper lip, dugongs are equipped to plow through large amounts of seagrass daily.
Dugongs leave feeding trails over 66 ft long in their wake! The mammals shrink seagrass meadows near urbanized areas through their intensive grazing. Conserving dugong populations requires careful management of seagrass habitats. After all, a hungry dugong needs massive amounts of marine salad.
Oxygen Production and Carbon Storage
Through the natural process of photosynthesis, seagrass generates oxygen just like plants on land. The meadows also act as “carbon sinks” – trapping significant amounts of carbon dioxide from the water and atmosphere. Seagrass provides vital climate regulation services below the waves.
Seagrass Meadows Pump Out Oxygen
Waving lushly underwater, seagrass produces copious amounts of oxygen just like a terrestrial forest. During photosynthesis, seagrass absorbs carbon dioxide and releases oxygen as a byproduct. The fitness trackers for seagrass would be off the charts!
A single hectare of seagrass can generate more than 17,500 pounds of oxygen per year – enough for over 100 people! This oxygen production benefits marine life in the immediate area, as well as adding to the ocean’s overall oxygen stores. Plus, higher oxygen levels during daytime aid the growth and productivity of the meadow.
Carbon Capturing Champs
In addition to churning out oxygen, seagrass meadows are excellent at capturing and storing carbon dioxide through photosynthesis. The plants incorporate much of this carbon into their living tissue. Then as older seagrass blades decompose, some carbon gets buried in the sediments below for millennia.
On average, seagrass meadows can stash away 83,000 tons of carbon per year globally – helping mitigate climate change impacts. That’s equivalent to over 33,000 passenger cars off the road! Their carbon sequestration ability makes seagrass a key player in the fight against global warming.
Protection Against Erosion
With their tangle of roots and rhizomes beneath the seafloor, seagrass plants stabilize sediment and help prevent coastal erosion. Their dense canopies also dissipate wave energy before it hits the shore. Seagrass buffers the impacts of storms and boat wakes that would otherwise degrade shorelines and impair water quality.
Seagrass Anchors Sediment
Have you ever tried to run on loose sand at the beach? Not easy! Now imagine you’re a grain of sediment being swooshed around by waves and currents. Thankfully, seagrass is there to catch particles and prevent erosion.
The mesh of tough underground stems and roots acts as an anchor for sediment. And the long blades help reduce water flow at the seafloor, enabling particles to settle. Areas with seagrass can have sediment deposition rates over 100 times higher than bare areas!
Filtering the Seas
As waves and currents pass through, seagrass traps floating sediment and debris before it reaches coral reefs or the open ocean. The leaves filter out excess nutrients from fertilizers and pollution that would otherwise harm marine environments.
Some seagrass species can remove up to 80% of ammonium and nitrate from the surrounding water. Seagrass minimizes our impacts on the sea by being the ocean’s kidneys, filtering out the bad stuff (don’t think about that metaphor too hard).
Threats to Seagrass
While seagrass provides incredible ecosystem services, it is also a highly threatened habitat worldwide. Due to human activities, the global extent of seagrass meadows has declined by over 30% in just the last century. Further losses have catastrophic implications for ocean health.
Pollution Poses Problems
Polluted runoff from agriculture and development feeds algal blooms and reduces water clarity – two big issues for seagrass. The plants need sunlight for photosynthesis, so murky waters smother meadows in darkness. Excess nutrients also allow seaweed and epiphytes to smother seagrass leaves.
Pesticides and chemicals from lawns and farms accumulate in marine sediments, poisoning invertebrates. Nitrogen and phosphorus overload leads to dead zones, which are spreading across once-lush seagrass areas like the Gulf of Mexico. Cleaning up land-based pollution is key for securing seagrass’s future.
Boats Wreak Havoc
Boating and fishing take a major toll on seagrass through direct physical damage. Boat propellers chop foliage, tear up rhizomes, and gash the seafloor. Anchor chains rake across meadows, leaving plowed scars. Heavy trawling nets crush and uproot plants.
Seagrass recovery from these disturbances is slow. Singapore has lost over 60% of their seagrass to reclamation and land transport. Solutions like boating restrictions and mooring buoys are needed to protect seagrass habitats.
Climate Change Causes Declines
Increasing sea temperatures, ocean acidification, and extreme weather all negatively impact seagrass meadows. Studies predict global warming will continue degrading seagrass due to heat stress, decreased productivity, and disrupted pollination.
The effects are already evident with the loss of 1,000s of acres of seagrass off Florida’s coast. Slowing climate change and improving seagrass resilience through restoration can help preserve these habitats for the future.
Conclusion
Seagrass meadows deserve their moment in the spotlight. These flowering plants nourish ocean wildlife, generate oxygen, store carbon, prevent erosion, and filter the seas. Yet seagrass ecosystems are disappearing at an alarming rate. Safeguarding remaining seagrass and restoring damaged meadows are crucial steps for sustaining ocean health.
Every small effort to protect seagrass counts – from reducing fertilizer usage to volunteering for beach cleanups. Seagrass roots us to the fact that even the most humble plants have an integral role in nature. Hopefully now you’ll look at seagrass blowing in the currents and appreciate the incredible impact of this special ecosystem.