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The
coastal habitats of Chek Jawa are submerged most of the time. A vast
expanse of Chek Jawa's rich intertidal zone is only exposed during
low spring tides. These low spring tides usually occur twice a month
and usually for only a few hours each time.
For sequence photos of how much of Chek Jawa
is exposed at various tide levels.
Tides in Singapore: Singapore
has two low tides and two high tides a day. The height of the tide
is not the same every day. High and low tides do not happen at the
same time every day, and the highest and lowest tide level change
every day. In Singapore, low spring tides generally occur in the late
afternoon to early evening for six months. This switches to early
morning for the next half year.
What affects the tides?
The timing and height of tides are influenced by the gravitational
effects of the moon, and to a lesser degree, that of the sun (because
it is much further away).
Spring Tides: During a full moon
or new moon, the moon and sun line up in a straight line. Their combined
gravitational effect Mid-high tideresults in an extra high and extra
low tide. This is called a spring tide because the water appears to
spring up.
Neap Tides:
At a quarter moon or three-quarter moon, the sun's gravity works at
right angles to that of the moon. This results in a smaller difference
in height between the low and high tide. This is called a neap tide.
The coastal area affected by the tides is called the intertidal
zone.
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Chek
Jawa's rich intertidal zone is submerged most of the time and exposed
only during low spring tide
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See
also ...
Why is the intertidal zone special?
Sequence photos of how much of Chek Jawa is exposed
at various tide levels
Links
Why Tides?
on the Fitzgerald Marine Reserve website: a wonderful animated gif shows
you clearly how spring and neap tides happen.
What
causes some tides to be 'plus tides' or 'minus tides'? on the Mad
Scientist website: Rob Campbell explains with lots of diagrams
Other references
- Tan, Leo W. H.
& Ng, Peter K. L., 1988. A Guide to Seashore Life. The Singapore
Science Centre, Singapore. 160 pp. online
version
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