- Estuaries are transitional zones where freshwater from rivers mixes with saltwater from oceans, creating brackish water. They are ecologically diverse and economically important habitats. - The largest estuary in Pakistan is the Indus River estuary, which supports mangroves and wildlife. Estuaries face threats from pollution, development, and climate change. - Conservation efforts include reducing water and energy use, properly disposing of chemicals, maintaining vehicles, and participating in community cleanups.

1. Hadia Mansoor
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2. Estuaries

3. What is Estuary?
• The transitional zone where freshwater from the rivers and streams
mixes with the saltwater from the oceans
• Bay, lagoon, sound, or slough
• Brackish water
• Salinity can range from 0.5 to 35 ppt.
• Water here is neither completely salty nor fresh

4. Characteristics
• Salinity: The amount of oxygen that can dissolve
in water, or solubility, decreases as salinity
increases
• Estuaries waters with salinities ranging between
20-31ppt.
• Temperature: In spring and summer, the
uppermost layer of an estuary grows warmer
• As air temperatures cool through the autumn, the
surface water becomes increasingly cold and
increases in density.

6. • Turbidity:
• Silt suspended causes the water to be turbid
• maximum during rainy season
• Turbid water prevents the light from penetrating.
• This reduces the level of photosynthesis by phytoplankton.
Nutrient Flow:
• Fertility of estuaries
• Drainage from the land, industrial effluents and city waters is the major source
• Crabs and microbes can transfer nutrients often in the form of detritus

7. Types of Estuaries
• Estuaries can be classified according to
their geological features.
• Coastal plain estuaries look like valleys
with gentle sloping bottoms. Their depth
increases towards the river's mouth. This
type of estuary is common throughout the
world.

9. • Fjord estuaries are narrow with steep sides and
are usually straight and long. Fjords are found in
areas that have been covered by glaciers.
• Bar-built estuaries are formed when sandbars
build up along the coastline and they partially cut
off the waters behind them from the sea.
• Tectonic estuaries are created when the sea fills
in a hole or basin that's formed from sinking
land.

10. Significance
• Breeding and nesting ground for many organisms
• Filter out sediments and pollutants , providing cleaner
waters for humans and marine life.
• Soil is nutrient-rich
• Nurseries of the ocean
• Phytoplankton which help the food chain and provide food for
many of the wildlife
• Buffer the Ocean and the land
• Decrease the effects of flooding and storm surges

11. Estuaries in Pakistan
There are three major estuaries in Pakistan:
Largest one being the Indus estuary on the Sindh coast
Hingol and Dasht estuaries both located in Balochistan
• Indus estuary that finishes up in the Indus Delta.
• Inlet of the Indus River
• Total coastal area of Sindh primarily south of Karachi.
• Landform that has mudflats
• Narrow creeks of old Indus estuaries are intervening in
these mudflats formed by Indus Delta.

12. Biodiversity
• Estuaries are home to variety of organisms like fishes, shell fishes,
lobsters, crabs, a wide variety of sea birds, goose, worms and many
different reptiles.

13. Sea turtles such as loggerhead and leatherback
turtles
• Graze on seagrass or rest
Two species of marine turtles occur in Pakistan–
• Olive ridley and Green turtle
• Nest at Hawksbay–Sandspit, a stretch of 20 km on the
Karachi coast
Estuarine crocodiles adapted to the brackish
water
• During the rainy season, estuarine crocodiles live in
freshwater rivers and streams
• Feed on fish such as barramundi, and terrestrial species
such as kangaroos and monkeys
• During the dry season, estuarine crocodiles swim to
river mouths and even out to sea
• Fish and Sharks

14. Ecological and Economic Importance
Beautiful and diverse habitats
• sandy beaches
• fresh and salt water marshes
• rocky shores
• shellfish beds
• oyster reefs mangrove forests
• river deltas
• sea grass meadows
• wooded swamps

15. • Indus Delta as a hub for seafood export
• Prevent soil erosion
• Unique plant communities.
• Prevent pollution, floods, and stabilize our shoreline.
• Harbors and ports vital for shipping and
transportation.
• Commercial and recreational fishing, boating,
water sports and tourism
• 30 million jobs
• Education, scientific knowledge, aesthetic and
natural practices.

16. Mangroves
• The mangroves in Pakistan are distributed among the
coastlines of Sindh and Balochistan.
• In Sindh, forests along the delta of the Indus River.
Largest mangrove forest in Pakistan. One of the top 10
mangrove forests in the world
• Waxy coating on their leaves to limit the take-up of salt
• Habitat for juvenile and adult fish, water birds, sea turtles,
mammals, molluscs and insects
• Drop organic matter into estuaries which provide food for a
range of animals
• Natural breakwater that protects and stabilizes the shoreline
• Improve water quality by filtering run-off from the land
• Store carbon and act as a ‘carbon sink’

17. wetlands
The U.S. Fish and Wildlife Service defined wetlands as follows in 1979
Wetlands are lands transitional between terrestrial and aquatic systems where
the water table is usually at or near the surface, or the land is covered by
shallow water.
TYPES
1-Marsh
2-Swamp
3-Bog
4-Fen

18. Significance
• Hydrophytes
• Exist in many kinds of climates, on every continent except Antarctica
• They vary in size from isolated prairie potholes to huge salt marshes
• They act like giant sponges or reservoirs
• Limit the effects of flooding
• Protect coastal areas from storm surges
• Water treatment facility
• It provides habitat to wildlife, migratory birds

19. • Pakistan, despite having an arid climate
• 780,000 ha of wetlands
• 9.7% of the total land area
• 225 nationally significant wetlands
• 19 have been recognised as Ramsar sites
Ramsar Convention:
• 1971
• small Iranian town of Ramsar
• Conserve and Halt the worldwide loss of wetlands
• International cooperation, policy making, capacity building and
technology transfer
• “Earth's kidneys" because of their high and long-term
capacity to filter pollutants from the water that flows
through them.

20. Freshwater complexes in Pakistan
• Northwestern Alpine wetland complex - Northern Areas
• Salt Range Wetland Complex - Punjab
• Central Indus Plain Wetland Complex - Punjab, Sindh,
• Makran Coast Wetland complex – Baluchistan
• Jawaani Wetland Complex - Baluchistan
• Deh Akro-II Desert Wetland Complex - Sindh

21. Threats
• Overloaded by the influx of sediments and pollutants
• Urbanization and infrastructure development
• climate change
• eutrophication
• harmful algal blooms
• shellfish and fisheries declines
• Use of the chemical superphosphate which could lead
to the increase in nutrient levels
• fuel the growth of algae in estuaries.
• Industries like fishing and oyster farming
• Impact the water quality and also the movement of water
in estuaries.

22. • Natural events are floods and sea storms
• Dams and power stations can change the water
temperature
• Boating can damage seagrass
• This can happen due to boat propellers
• The destruction of fringing wetlands and the loss and
alteration of estuarine habitats usually degrade biotic
communities.
• Human activities affect wildlife

25. Conservation
• Conserve water in your daily life.
• Install water-saving toilets and showerheads.
• Replace dripping faucets and leaky pipes.
• Dispose of household and yard chemicals properly
• Reduce, re-use and recycle every day.
• Maintain your cars and other heavy equipment to reduce oil leaks.
• Minimize use of fertilizers and pesticides on your yard.
• Keep your boat or motorized watercraft out of sensitive areas like seagrass beds.
• Install and maintain marine sanitation devices on your boat.
• Pick up trash; participate in trash clean-up days.
• Help plant trees or seagrass, or remove invasive vegetation.
• Don't litter