Seagrass

Seagrass is extremely important for the health of Florida’s marine ecosystems.

Seagrass are actually flowering plants which live underwater in marine and estuary waters. Seagrasses are found throughout Florida, and are most abundant in the northwestern Gulf of Mexico and in Florida Bay.

Seagrasses also thrive throughout the Florida Keys, and in the Florida Keys National Marine Sanctuary.

Seagrass beds usually grow best in lagoons and protected bays, but can also grow in deeper water in the Gulf of Mexico.

Seagrass is heavily reliant upon sunlight, which is required for photosynthesis. Water depth and clarity are two important factors for seagrass health, since both can limit the amount of sunlight which reaches seagrass beds on the seafloor.

Florida Bay has more than 850 square miles of pristine marine ecosystem. The region is filled with mangroves, seagrass beds and shallow basins which are filled with marine life.

Florida By is one of the world’s most ecologically productive habitats. Researchers have documented hundreds of species of fish and other marine life in the span of a single square meter. Most forms of marine life depend on seagrass beds for shelter, food, or other uses.

Importance of Seagrass

Seagrass performs a variety of important tasks:

  • Prevent erosion
  • Filtering pollutants
  • Provide food for manatees, sea turtles and other marine life
  • Provide shelter for juvenile marine life
  • Absorb nutrients
  • Reduce turbidity and preserve water clarity
  • Dampen wave energy and ocean currents
  • Absorbing and storing carbon dioxide
  • Oxygenate water

Seagrass die-offs can jeopardize the health of entire ecosystems and can have enormous downstream consequences and knock-on effects. Countless marine organisms rely on healthy seagrass beds for survival.

Seagrass Die-offs

Seagrass die-offs occur for a variety of reasons:

  • Excessive salinity, due to reduced flows of freshwater
  • Pollution
  • Red tide and algae blooms
  • Excessive sulfur
  • Excessive nutrients
  • Diseases and parasites
  • Physical damage from boat propellers, groundings, anchoring and trampling
  • Overgrazing by organisms, including sea urchins

Types of Seagrass in Florida

Seven species of seagrass are found in Florida.

  • Turtle grass (Thalassia testudinum)
  • Shoal grass (Halodule wrightii)
  • Manatee grass (Syringodium filiforme)
  • Widgeon grass (Ruppia maritima)
  • Stargrass (Halophila engelmannii)
  • Paddle-grass (Halophila decipiens)
  • Johnson’s seagrass (Halophila johnsonii)

Cover Photo courtesy of Benjamin L. Jones, Marine biologist and founder of marine conservation organisation Project Seagrass.