KOROR STATE GOVERNMENT MARINE TOUR GUIDE ... - C3

Pat Colin
Role on the reef
Most sponges stand out from the reef community with their bright colors and range of
shapes. Some of the most important sponges on the reef are those that you cannot see.
Boring sponges break down the limestone skeletons of corals and the use the space
created as a home. This is one of the major ways that coral is broken down into sand
and rubble.
Feeding
If you inspect a sponge closely, you will find its surface is covered in small and large
pores. Water is drawn in through the small pores and through a series of canals until it
enters feeding chambers where food particles as small as bacteria are digested. Water
is expelled from the sponge through the large volcano-like pores. Many sponges contain,
like corals, algae that can produce food for them by using light from the sun.
A sponge the size of a cup could filter 5000 liters of water a day!!
Reproduction
Sponges can reproduce asexually by budding and breaking off segments. Most sponges
also have both male and female sex organs. During sexual reproduction, eggs are
retained by the sponge. Sperm are released into the water and are taken up by other
sponges to fertilize their eggs.
Human Use and Impacts
Sponges are being explored for their biomedical properties. Many contain toxins for selfdefense
and these are being explored for their potential use as drugs for the treatment of
various diseases, including cancer. Being filter feeders, sponges can easily become
clogged by sand kicked up by divers and snorkelers.
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