About:

Sea- grasses are (angiosperms) marine flowering plants that resemble Grass in appearance.

• They produce flowers; have strap-like or oval leaves and root system.
• They grow in shallow coastal waters with sandy or muddy bottoms and require comparatively calm areas.
• They are the only group of higher plants adapted to life in the salt water.
• Major sea grass meadows in India occur along the south east of Tamil Nadu and in the lagoons of a few Lakshadweep islands. There are few Grass Beds around Andaman and Nicobar islands also.
• The rich growth of sea grasses along the Tamil Nadu coast and Lakshadweep islands is mainly due to high salinity, clarity of the water and sandy substratum.

Functions:

1. Sea grass beds physically help

• To reduce wave and current energy,
• To filter suspended sediments from the water and
• Stabilize bottom sediments to control erosion.

1. Provides habitat for marine invertebrates and fishes.
2. Sea grass beds are widespread in lagoon and in such areas; the population of fish and migratory birds are also higher due to the availability of food and shelter.
3. Sea grasses on reef flats and near estuaries are also nutrient sinks, buffering or filtering nutrient and chemical inputs to the marine environment.

Threats:

• Eutrophication
• Siltation
• Trawling and coastal engineering constructions
• And over exploitation for commercial purposes.

Advantages:

• Sea grasses are considered ‘Ecosystem Engineers’ as they are known for providing many ecosystem services and are also called ‘the lungs of the sea’ as they release oxygen into the water through photosynthesis.
• Sequesters up to 11% of the organic carbon buried in the ocean even though they occupy only 0.1% of the ocean floor and absorb 83 million tonnes of carbon from the atmosphere annually.
• Help maintain water quality by trapping fine sediments and suspended particles in the water column and increase water clarity.
• Filter nutrients released from land-based industries before they reach sensitive habitats like coral reefs.
• Prevent soil erosion as the extensive vertical and horizontal root systems of sea grasses stabilize the sea bottom.
• Provide food as well as habitat for fishes, octopuses, shrimp, blue crabs, oysters, etc.
• Protect juvenile and small adult fish from large predators and also protect worms, crabs, starfishes, sea cucumbers, sea urchins, etc, from strong currents.
• Provide ideal nursery sites for important commercial marine life like squids and cuttlefish.

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