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sand bar

sandy ecosystems on Chek Jawa (coloured portion)

Sandy shore and sand bar
On Chek Jawa, sandy habitats are found on the shore and outer sand bar. These may appear barren, but many animals live here. Most sand-dwellers burrow deeply into the sand to stay moist at low tide. Here, they are also safer from predators.

What is sand made of? Sand is made up of weathered rocks; and the broken shells and bones of sea creatures

Microscopic universe in the sand: Together, sand grains form an entire galaxy of invisible life in the sand! Each grain of sand is surrounded by a thin film of water. Swimming about in this film are microscopic plants and animals. These microscopic lifeforms are eaten by tiny animals and in turn by slightly larger ones. Many food chains on Chek Jawa begin with such humble creatures.

Rough life: For larger animals, living in sand is like living in moving sandpaper. Sand particles are abrasive and move with the currents. Some worms cope by making protective tubes. Water drains quickly through sand, so the upper layer may be quite dry. Most sand-dwellers burrow deeply into the sand to stay moist during low tide. Here, they are also safer from predators.

cartoon by chim chee kong

When we step on sand, the grains are squeezed more closely together (this is called compaction). We may thus crush unseen creatures or make it harder for them to burrow. Please stay on the designated route so as to limit the area that is compacted.

A closer look at sand

See also ...
Why are there so many Carpet anemones on the sand bar? Instead of staying in the cool pools at low tide, many Carpet anemones are found on the sand bar. Here is a possible explanation for their strange behaviour.

Links
Sandy Beach on the Lane Community College website: brief introduction to sandy beaches and a few of their inhabitants.
Seaweed also plays a role in the formation of sand on SusanScott.net: what really produces sand? Rocks? Think again...
Sand grains on Wayne's Word: more about sand with lots of photos.
Why are the grains of sand so uniform in size? on the Mad Scientist website: Eli Hestermann explains how waves sort sand grains by size.

Other references

a companion website to the chek jawa guidebook website©ria tan 2003 www.wildsingapore.com

a companion website to the chek jawa guidebook
website©ria tan 2003 www.wildsingapore.com