Gorgonian


Gorgonian, commonly known as the sea fan or sea whip, is similar to a soft coral in the Cnidarian Phylum. Over 1200 species (to date) of Gorgonians have been classified. Gorgonians are found throughout the oceans of the world, but mainly in the tropics. (For example: Caribbean)


Kingdom Animalia

Phylum Cnidaria

Class Anthozoa

Order Gorgonaceae

3 Suborders
1. Holaxonia
2. Scleraxonia
3. Calcaxonia


Fan-like Form, Sea Fan
Fan-like Form, Sea Fan
Feathery-whip like form, Sea Whip
Feathery-whip like form, Sea Whip


















Striking resemblance to plants, but they are classified as animals. Most gorgonians are photosynthetic, and are found closer to the surface of the water. The non-photosynthetic ones are found deeper in the water, or in shaded areas. They are generally yellow, orange or red. Gorgonians have diverse shapes, sizes, colors, method of obtaining nutrients, they all generally share a common structure.

Structure & Morphology

All gorgonians are covered with small polyps, and the polyps form colonies that are usually erect, branching, flattened, bushy, or whip-like, depending on the species. Colonies tend to grow up to several feet high, but they remain quite thin. They have a central stem that all the branches extend out of, and the stem attaches the organism to hard surfaces(corals or rocks) or soft bottoms (mud/sand).
There are 2 types of polyps:
1. Autozooid Polyps: They consist of 8 pinnate tentacles and 8 septae. The tentacles catch the plankton and organic matter that the current brings to them and moves the food to the mouth in the center. The septae's role is to distribute the food throughout the colony because they have interconnecting channels.
2. Siphonozooid Polyps: They have reduced tentacles and their role is to pump water into the colony. By doing so, the structure remains erect and water supplies oxygen.

Feeding

Most gorgonians have a symbiotic relationship with zooxanthellae.
They capture plankton and organic particles and absorb the the digested material.
Photosynthetic ones require light to survive.


Diodogorgia nodulifera

Common Names: Red/Yellow Tree Gorgonian, Sea Blade, Finger Coral, Colorful Sea Rod


Habitat:

They are found under ledges, cave walls, shady areas, and usually deep in the water ( 50-500ft ). Since they are nonphotosynthetic, the Colorful Sea Rod lives in areas with less light.

Description:

The Colorful Sea Rod grow to about 10 inches, and they have small, sparsely branched colonies. Their branch pattern is Y-shaped and is made of a gorgonin, a protein-substance.
D. nodulifera comes in two color forms:
1. Red Finger Gorgonian: deep red branches, with red or yellow calyces (raised cups) that white polyps rise out of.
2. Yellow Finger Gorgonian: orange to yellow branches, with red or violet calyces (raised cups) that polyps rise out of.



Red Finger Gorgonian
Red Finger Gorgonian
Yellow Finger Gorgonian
Yellow Finger Gorgonian

Feeding:

This species does not have symbiotic relationships with algae or zooxanthellae, so they primarily depend on the zooplankton and other organic particles that are in the water columns.


Reproduction:

There is no physical difference between genders. They reproduce by breakage and refragmentation, and spawn (sexual reproduction).