1. Ecology of Sandy Beaches

2. Expectations
?? ?

3. Objectives The Biological Study of Sandy Beaches
Typical sandy Beach animals (Characters & features)
Cryptic animals
Meiofaunal Vs Macrofaunal Sand Sample
The importance of developing and understanding of sandy shore ecosystems.
Physical Environment.
Sand.
Waves: Surface gravity, Internal & Edge waves.
Wind.

4. The Biological Study of Sandy Beaches
When has the biological study started?
It started only fifty years ago after intensive studies of rocky shore.
Why was there an early neglect of sandy beach ecosystem?
It seems always devoid of life (why?).

5. The early neglect of sandy beach ecosystem was due to
Rocky shore
1- Obvious life-presenting fascinating prospect to scientific research.
2- Plants & animals are large and highly colored.
3- Many animals are sessile or very slow moving, easy to collect and study.
Sandy Shore
1- No attached plants.
2- Animals are so small. 3- Few species of macrofauna are cryptic.
4- On sheltered beaches burrows excavated by Arenicola and Callianosa (evidence to life).
5- On exposed beaches, sand is unstable to support burrows intertidal.
6- Animals are highly mobile to maintain their position.

6. Cryptic animals They are hiding within sand.
They appear only when necessary to feed, perform other vital functions.
Mobility and cryptic mode of life render sandy beach observations.

7. Typical sandy Beach animals (Characters & features)
1- Millimeter or so in length. Small enough to live and move between sand grains.
2- Migrating up and down through the sand column in response to environmental factors.
3- Those animals are named MEIOFAUNA
4- Although the collection and identification of meiofauna is difficult than macrofauna, the diversity of meiofauna is higher than macrofauna.

8. Meiofaunal Vs Macrofaunal Sand Sample
A single sand sample
Numerous species of A
Nemertina M N
Turbellaria U
Tardigrada E A
Foraminifera I F O
Nematodes
Ostracoda
Annelids
Gastrotrichs
Harpacticoida

9. Very Few Species of In Contrast:
Typical permanent intertidal sandy beach MACROFAUNA
Very Few Species of
Polychaete
Mollusca
Donax sp.
Two or few Crustacea species
Although of this distinction, macrofauna has intensively studied
Our knowledge about meiofauna and microbiota are poor.

10. The importance of developing and understanding of sandy shore ecosystems
¾ of the world’s
Ice free coastline
Consists of sandy
Shores.
Appropriate management
& successful conservative
Can only be achieved.
Beaches and dune
Systems are fragile
ecosystems need
management.

11. Physical Environment Physical Habitat Structure is determined by Sand
Sandy Coastal line = Shores +Beaches
It is Dynamic environment
Physical Habitat Structure is determined by
Sand
Air
Water

12. Sandy Beach is one of the most stable dynamic coastal line (why?).
Due to its ability to absorb wave energy.
Beach is characterized by
Wave driven sand transport
Aeolian (wind) transport
Sediment transport in
Dunes by wind action.
Sediment transport in
Surf zone by wave action.

13. Originates from

16. Surface Gravity Waves:
1-Generated by wind stress on water surface.
2-Friction (wind & water)
3-A viscous drag
4- Stretches the surface like an elastic membrane
undulation
Wind
Surface
tension
waves
Distortion
Restoration

17. What happens if strong wind blows up?
1-Waves grow.
2-Gravity replaces surface tension.
3-Waves move off before the wind.
4-Waves transfer energy from wind at sea to coastal zone.

18. Internal waves Generated by Tide Wind
They occur at the boundary between water layers of different densities.
Generated by
Tide
Under water
avalanches
Wind
Internal waves may causes fluctuations in surf zone

19. Edge waves
They are waves running along the shore and contained in surf zone.
ًWind
They are important in shaping wave characteristics.
Surface water movement is about 2% of wind speed.
Strong on shore winds
Off shore winds
Wave Height
Size of surf zone
Wave Height
flatten
Size of surf zone
Affect sediment transport between Beach and Dunes

20. ٍٍ
Summary

21. Sand Movement Sand moves in two ways Bed Load Suspended Load
It is moving close to the bed
Coarser materials
Suspended Load
It is transported above Bed
Finer materials
The steeper the waves and the beach,
the greater the tendency for accretion.

22. In Practice:
Strong erosion or sea ward movement of sediment for short periods
Is balanced by
Gradual accretion or land ward