Seagrasses are Huge Stores of Blue Carbon

Seagrass meadows are nursery habitats for many important fish species. Photo: Heather Dine/NOAA

In This Article:

  • What Are Seagrasses?
  • Where Do Seagrasses Grow?
  • Why Are Seagrasses So Important?
  • 1. Important Carbon Sinks
  • 2. Keep Oceans Healthy
  • 3. Foundation of Marine Food Web
  • 4. Nursery For Younger Fish
  • 5. Fishing Industry
  • What Are The Threats To Seagrass Meadows?
  • How Can We Protect Seagrasses?
  • Further Reading
  • References

What Are Seagrasses?

Seagrasses are like secret gardens under the sea.

Seagrasses seen from Space. Astronaut photograph shows part of the Al Wadj Bank, located along the northern Red Sea coast. This area has a healthy and diverse coral reef system and extensive seagrass bed. You can see several islands (tan), surrounded by dark green seagrass — the largest is at top left. Image: NASA

Where Do Seagrasses Grow?

Seagrasses need lots of sunlight for photosynthesis to grow. That is why they are generally only found in shallow coastal waters, up to depths of about 4 meters (13 feet).

Why Are Seagrasses So Important?

1. Important Carbon Sinks

Seagrasses are ‘wonder plants’ that help to mitigate climate change by removing carbon dioxide from the atmosphere. They absorb about 10 percent of carbon dioxide in circulation, despite only populating 0.2 percent of the seafloor.

2. Keep Oceans Healthy

Seagrass ecosystems are highly productive and help keep the ocean healthy. Known as the ‘lungs of the sea’, one meter (3.2 feet) of seagrass can generate 10 liters of oxygen every day through photosynthesis. (3) Marine animals absorb dissolved oxygen through water and use it to breathe, grow and reproduce.

3. Foundation of Marine Food Web

Seagrass meadows are important feeding grounds for thousands of species of marine wildlife.

4. Nursery For Younger Fish

Like coral reefs, seagrass meadows provide critical nursery grounds for baby fish, including commercially important fish species like cod, plaice and pollock. They also offer shelter from predators to invertebrates like crabs and shrimp.

5. Fishing Industry

Seagrass meadows are essential to the fishing industry because they provide the nursery ground and food for their catch. Catch such as the Walleye pollock, Atlantic herring and cod and Pacific herring and cod.

Manatee grass (Syringodium filiforme) in southeastern Graham’s Harbour, San Salvador Island, Bahamas. It is the favorite food of the manatee, more commonly known as the sea cow. Image: James St John. CC-BY — 2.0

What Are The Threats To Seagrass Meadows?

Despite their importance — seagrasses are disappearing at the rate of 7 percent a year since 1990. (6) That’s about 2 football fields worth of meadow lost every hour.

How Can We Protect Seagrasses?

There is no international legislation to protect seagrasses, so typically protection comes from local agencies. However, countries that have signed up to the Paris Climate Agreement are placing increased focused on restoring lost seagrass meadows as a way of meeting their National Determined Contributions (NDC’s).

Further Reading

Seagrass Research in Southeast Asia, Indonesia and Philippines — a biologically diverse region threatened by anthropogenic activities. Jillian Lean Sim Ooi et al, 2018.

References

  1. “The global distribution of seagrass meadows.” Len J McKenzie et al. 2020.
  2. “The ocean, a carbon sink.” La Plateforme Océan et Climat (POC) ocean-climate.org/ Dec 3, 2016.
  3. Sea grasses and sea grass beds — Ocean
  4. “Seagrass meadows support global fisheries production”. Richard K.F. et al.2018
  5. “Global significance of seagrass fishery activity”. Lina M Nordlund et al. November 2017
  6. “Disappearing Seagrass Threatening Future Of Coastal Ecosystems Globally” University of Maryland Center for Environmental Science. 2009

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Karina Collins

Karina Collins

I work in marketing by day — and pen my thoughts on climate change by night.