The United Nations recently declared today, March 1st, as World Seagrass Day in a bid to raise awareness of the threats these essential marine habitats currently face. So firstly, happy World Seagrass Day! Secondly, here’s 7 things absolutely everyone should know about seagrass – as broken down by The Ocean Agency.
1. SEAGRASS = FISH
Seagrass beds are a vital habitat for many ocean species, from fish to crustaceans to seabirds. But fish are the primary marine animals that rely on seagrass beds when they’re young. Just 2.5 acres of seagrass bed can support over 80,000 fish, making them the basis of the world’s primary fishing grounds. In fact, they supply about 20% of the world’s fisheries.
2. SEAGRASS = CLIMATE ACTION
As oceans warm due to climate change, they also become more acidic, posing great threats to important ecosystems like coral reefs. However, seagrass beds can effectively fight ocean acidification. Studies have shown that seagrass meadows can actually reduce water acidity by up to 30%. Seagrass beds are also vital for carbon capture and can help prevent ocean acidification and other effects of climate change in the first place.
3. SEAGRASS = CORAL REEFS AND MANGROVES
Seagrass beds don’t just help individual marine creatures — they also work with entire ocean ecosystems like coral reefs and mangroves to support overall ocean health. Mangroves, which are nearer to shore, help filter pollutants out of runoff water that comes from the land and act as a nursery habitat for juvenile fish. Seagrass beds are a buffer and a connecting zone between coastal forests and coral reefs, further purifying water and providing safe feeding and nursery grounds for juvenile reef fish. Finally, the reefs themselves are a critical ecosystem for over 25% of all marine life.
4. SEAGRASS = SURVIVAL
Seagrass meadows are home to a number species on the IUCN Red List of Threatened Species, like dugongs, seahorses and green sea turtles. Some of these species graze on the seagrass directly, while others get nutrients from the habitat indirectly. For example, bottlenose dolphins often forage on organisms that live in seagrass, like crustaceans and squid. Filter feeders like sponges also love seagrass, as there’s a lot of detritus and plant matter that builds up around the beds as grasses die and new ones grow.
5. SEAGRASS = PROTECTION
Another thing seagrass beds have in common with mangroves and coral reefs is that they help protect shorelines from coastal erosion. Swells and surges from currents and storms get broken up when they pass over seagrass beds. You may think storms and intense wave action would wreak havoc on seagrasses — and they sometimes do — but most often, seagrass is able to withstand strong currents due to its extensive root system that extends both horizontally and vertically.
6. SEAGRASS = WEALTH
Seagrasses are an important ecosystem for coastal communities, providing nutrition for close to 3 billion people. They also support about 50% of animal protein consumed by more than 400 million people in developing countries. Seagrass beds supply a total of about 20% of the world’s fisheries, and communities in developed nations have established an economic dependence on them as well. For example, in the Florida Keys, seagrass beds were reported to bring in nearly $14 million in stone crab, spiny lobster, shrimp, yellowtail snapper, gray snapper, and blue crab harvests in 2010.
7. SEAGRASS = CLEANER OCEAN
One reason marine animals flock to seagrasses is that the water surrounding them is cleaner than most other parts of the ocean. This is because the grasses themselves help trap fine sediments and suspended particles, clearing the water column. Sand patches without seagrass can be stirred up by wind and waves, which affects the quality of the area both for marine life and human recreation. Seagrasses also filter nutrients in runoff from land, protecting coral reefs from contaminants.