THE GRACEFUL CREATURE OF THE SEAFLOOR
The sea pen is graceful creature of the seafloor; this sea pen resembles a plump, old-fashioned quill pen. Its colors range from dark orange to yellow to white. They live at many depths from shallow waters down to deep seas in tropical and temperate water worldwide.
Each sea pen is a colony of polyps, small anemone like individuals working together for the survival of the whole.
The primary polyp loses its tentacles and becomes the stalk of the sea pen with a bulb at its base. The bulb anchors the sea pen in the muddy or sandy bottom. They feed on phytoplankton and detritus particles.
The red star, the leather star and the three types of Nudibranchs prey on sea pens. When touched, sea pens emit a bright greenish light; this is known as bioluminescence. when disturbed, a sea pen forces water out of the colony, making it possible for them to retreat into its bulbous foot.
Recent research shows that the population of Sea pen has declined in some areas. A large number of their predators like sea stars and Nudibranchs have also disappeared, leaving some sandy-bottom areas vacant. This affects the population of these creatures at the top of the food chain too.
The various secondary polyps form the sea pen's branches and have specialized functions. Some polyps feed by using nematocysts to catch plankton.
Once plentiful in parts of Puget Sound, sea pen populations have declined in those areas. Their absence can indicate an ecosystem in trouble.
Really Interesting
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