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Difference between Sea Grass and Sea Weed

Difference between Sea Grass and Sea Weed


  • Sea grasses are specialized marine flowering plants that resemble actual grass. They grow in shallow, coastal waters with muddy bottom and require comparatively calm areas.
  • Sea grasses are the only group of higher plants (flowering plants) adapted to live in sea water.
  • Major sea grass meadows in India are in the south-east coast of Tamil Nadu, coast of Lakshadweep Islands and a few around the Andaman and Nicobar Islands.

Functions of Sea Grass

  1. Sea grass reduces the energy of ocean waves. Thus, it provides calm habitat to many species.
  2. It filters suspended sediments from water.
  3. It stabilises bottom sediments to control coastal sand erosion.
  4. It acts as a habitat for many marine species.
  5. It helps in the storage of nutrients from ocean water.
  • Due to its importance, the protection of sea grass has been accorded high priority.
  • Sea grass is present from the inter-tidal zone to nearly eight metre depth of the Continental Shelf.
  • Dugong (sea cow) is dependent on sea grass for its existence. Fast destruction of sea grass is leading to Dugong’s extinction.


They are algal in nature. They are found attached to rocks, corals and other submerged strata in the shallow sub-tidal zones. Sea weeds are classified on the basis of their pigmentation as blue-green, green, brown, red, etc.

Sea weeds serve various useful purposes:

  1. They are food for many marine organisms.
  2. Habitat for fish breeding.
  3. Stores sediments.
  4. Serves other useful purposes such as:
  5. Food for humans.
  6. Feed for animals.
  7. Fertilisers for plants.
  8. Used in medicines for intestinal disorders, goitre, etc.
  9. Used for making iodine.
  10. Biodegradation of sea weeds produces methane gas.
  11. They are also used in antibacterial activity.
  12. They also assist in bioremediation. Sea weeds bind and accumulate heavy metals.

Harmful Effects of Seaweeds

Rotting sea weeds release hydrogen sulphide (H,S) gas, which is highly toxic and poisonous.

Threats to Sea Grass and Sea Weeds

  • Construction in the coastal regions.
  • Siltation of coastal regions (if silt gets deposited).
  • Eutrophication of water bodies.
  • Trawling (use of large nets to capture fishes).


  • Algaculture is a form of aquaculture involving the farming of species of algae.
  • Algae have many commercial and industrial uses, but due to their size and the specific requirements of the environment in which they need to grow, they do not lend themselves as readily to cultivation.
  • Commercial and industrial algal cultivation has numerous uses, including the production of food ingredients such as omega-3 fatty acids, natural food colourants and dyes, food, fertiliser, bioplastics, chemical feedstock (raw material), pharmaceuticals and algal fuel.            Difference between Sea Grass and Sea Weed
  • Algae can also be used as a means of pollution control.

Environment & Biodiversity

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