What is seagrass?
Seagrass is a marine plant – and it is the only flowering plant that can live under ocean waters. There are four major groups of seagrasses divided into around 60 to 70 species. Seagrass can sometimes be mistaken for seaweed, which is algae that does not have a true root system and reproduces via spores.
Seagrass is found in intertidal (exposed at low tide) and subtidal (constantly submerged) habitats around most continents of the world, and around many reefs and islands. The Great Barrier Reef Marine Park is home to one of the largest seagrass ecosystems worldwide.
Why is seagrass important?
Seagrass meadows provide a range of valuable and interconnected ecosystem services, including:
Food for marine animals and shorebirds – seagrass is the main food source for dugongs and sea turtles, and shorebirds can forage for food in coastal meadows.
Carbon capture and storage – by efficiently capturing and storing carbon, seagrass meadows help to reduce levels of carbon dioxide in the atmosphere.
Nursery habitats – seagrasses support important fisheries by providing sheltered habitats for young marine animals.
Coastal protection – the roots and rhizomes of seagrass hold sediment in place, reducing erosion, and some seagrass meadows can reduce wave energy.
Water filtration – by filtering out nutrients and trapping fine sediments from the water, seagrasses improve water clarity and are likely to protect corals from disease.
The health of seagrass meadows – and the ecosystem services they provide – are threatened by several direct and indirect factors such as heat stress, runoff from land, human activities, and severe storms.
Our work with seagrass
As one of Australia’s largest tropical seagrass research groups, we lead a range of seagrass projects across northern Australia that include:
Mapping – we work with Traditional Owner groups across northern Australia to map where seagrass meadows can be found.
Long-term monitoring – we work with Traditional Owners and industry across the Great Barrier Reef coastline, Torres Strait, and Gulf of Carpentaria to monitor seagrass in the same areas each year. Long-term monitoring allows us to understand how meadows are changing and identify when scientific advice to management is needed.
Restoration – we are trialling methods to restore seagrass in areas where meadows have been damaged or lost, such as Mourilyan Harbour.
Related projects:
