Have you ever thought about seagrass? If you’ve walked into the ocean and tiptoed between the slimy blades waving with the tide, you’ve trodden upon seagrass. I must admit, I’ve always considered seagrasses to be an annoyance. They block my view of the ocean floor and feel icky on my feet. I couldn’t understand their value or purpose. I was so wrong.
First, seagrasses are plants, not seaweeds. They act as the “lungs of the sea.” They can photosynthesize up to 10 liters of oxygen per square meter per day. Further, a single acre of seagrass can support more than 40,000 fish and 50 million small invertebrates such as snails, sponges, and sea anemones. They are literally biodiversity hotspots.
This is more than enough to solidify their worth, but they do still more. Seagrasses filter the surrounding water, removing excess nitrogen originating from chemicals. Too much nitrogen can contribute to acidification and diminish the ocean’s health.
Another contributor to acidification is carbon dioxide. Again, seagrasses help to correct the issue. They absorb carbon as they photosynthesize. Seagrass meadows are up to 35 times more effective than the Amazon rainforest in their carbon uptake and storage abilities.
The impact of acidification is profound. As an example, it causes juvenile oysters to struggle to build and maintain their shells. Even slight acid increases can dissolve their calcium carbonate infrastructure. This is just one of many consequences resulting from an acid imbalance in the ocean.
Seagrasses offer at least one more vital benefit. We’ve heard a lot about the benefits of mangroves to prevent coastal erosion, but seagrasses are equally important in this battle. Seagrasses reduce the force of waves with their leaves and encourage the sediment carried in the water to drop to the seafloor, not accumulate further onshore.
Again, a seemingly inconsequential plant is actually a necessity for the sustainability and survival of many other species. I have a new respect for seagrasses.
Smithsonian Ocean Portal on seaweed – https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-seagrass-beds
More about seagrass and nitrogen filtration – https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lno.11241
More about seagrass and carbon dioxide buffering – https://www.ucdavis.edu/news/seagrasses-turn-back-clock-ocean-acidification
and here – https://oceanfdn.org/calculator/why-go-blue/
A monograph about seagrass – http://www.reefresilience.org/pdf/Managing_Seagrass_for_Resilience_to_CC.pdf