lagoons are diverse aquatic ecosystems with unique hydrological and ecological characteristics, ranging from coastal formations influenced by tides to freshwater bodies impacted by human activities. Understanding the different types of lagoons and their ecological functions is essential for effective conservation and management of these valuable coastal resources.

1. LAGOONS
By
Er. T. AYISHA NAZIBA, Dr. S. PUGALENDHI

2. Lagoons
 Lagoons are shallow bodies of water, often found along
coastlines or inland, characterized by their still or
slow-moving nature and usually lacking in wave
action. Lagoons can form naturally or be artificially
created, serving various ecological, recreational, and
industrial purposes.

3. TypesofLagoons

4. CoastalLagoons
 Coastal lagoons are found along coastlines and are
typically separated from the open ocean by barrier islands,
spits, or sandbars.
 They may be connected to the ocean through narrow inlets
or channels that allow for limited exchange of water with
the sea.
 Coastal lagoons can be classified into different types based
on their formation and hydrological characteristics:
 Bar-built Lagoons: Formed behind barrier islands or spits,
often separated from the ocean by a narrow barrier.
 Tombolo Lagoons: Found behind tombolos, which are ridges
of sand or gravel connecting an island to the mainland.
 Lagoon-inlet Lagoons: Connected to the ocean by tidal inlets
that control water exchange.
 Atoll Lagoons: Enclosed within coral atolls, which are
circular coral reef formations surrounding a central lagoon.

6. Atrophic
Lagoons
 Atrophic lagoons are freshwater or brackish lagoons
characterized by high nutrient levels, often resulting in
excessive algae growth (eutrophication).
 They can be formed naturally in areas with slow water
circulation or can be human-made, such as wastewater
treatment lagoons or agricultural runoff retention
ponds.

7. CoastalPlain
Lagoons
 Coastal plain lagoons are formed in coastal lowland areas,
often associated with river deltas or estuaries.
 They are influenced by both freshwater inputs from rivers
and tidal movements, creating a mix of fresh and
saltwater conditions.

8. Industrialor
Wastewater
Lagoons
 These lagoons are human-made and used for the
disposal or treatment of industrial wastewater, sewage,
or agricultural runoff.
 They serve as containment basins where pollutants can
settle out or be treated through natural processes
before discharge or further treatment.

9. Saltwater
Lagoons
 Saltwater lagoons are connected directly to the ocean
and experience significant tidal fluctuations.
 They are common in coastal regions with irregular
shorelines or where barrier islands or reefs create
sheltered areas.

10. Characteristics
ofLagoons
 Water Circulation: Lagoons often have limited water
circulation and may experience stratification, with
warmer, lighter water at the surface and cooler, denser
water at the bottom.
 Biodiversity: Lagoons support diverse ecosystems,
including aquatic plants, fish, shellfish, and migratory
bird species.
 Sediment Accumulation: Lagoons can accumulate
sediments, including silt and organic matter, which
contribute to their ecological productivity.
 Human Use: Lagoons are valued for recreational
activities such as boating, fishing, swimming, and
birdwatching, and they may also be important for
aquaculture and tourism.

11. Environmental
Importance
 Lagoons play a critical role in coastal ecosystems by
providing habitats for marine and estuarine species,
serving as nurseries for juvenile fish, and filtering
pollutants from runoff.
 They act as buffers against storm surges and erosion,
helping to protect coastal communities from natural
hazards.

12. Management
and
Conservation
 Lagoon ecosystems require careful management to
mitigate the impacts of human activities such as
pollution, habitat destruction, and overfishing.
 Conservation efforts focus on preserving lagoon
biodiversity, restoring degraded habitats, and
promoting sustainable use of lagoon resources.

13. THANK
YOU