Green reef sea divide
| Green reef sea divide | ||||||||||||
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Didemnum molle , outlined in green, is the common egestion opening (outflow opening) of all individual animals. When enlarged (by clicking on the picture) you can see the small individual ingestion openings (inflow openings) of the individual animals. |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Didemnum molle | ||||||||||||
| Herdman , 1886 |
The Didemnum molle ( Didemnum molle ) is a sessile, colonial ( animal sticks forming) tunicate (Tunicata), the very numerous in the coral reefs of tropical Indopazifik occurs. The Green Reef Sea Squirt lives on exposed hard soils at depths of one to 70 meters. The animals are among the most common sea squirts and also colonize artificial substrates such as old fishing lines or fishing nets.
features
The colonies are spherical, barrel or urn-shaped and reach a height of three to ten centimeters. At the top is the outflow opening of the common cloaca space for all individual animals ( zooids ), the outer wall of the colony is littered with tiny inflow openings, one for each individual animal. A single zooid is only 1.5mm long. The mantle contains spherical, morning star-shaped limestone elements (0.005 to 0.015 mm in diameter), but the outer skin is very soft. The fine threads with which the green reef sea scabbard attaches itself to the substrate also contain these calcareous clerites. The colony is whitish, green-white or brownish in color. Young colonies are mostly green. The color depends on pigments, the concentration of calcareous sclerites and the cyanobacteria of the genus Prochloron , which live in symbiosis with the green reef sea squirt and colonize the common cesspool of the colony. The interior and the edge of the discharge opening are colored intensely green by the prochloron cyanobacteria. The Green Reef Sea Squirt partly feeds on nutrients produced by the prochloron bacteria. Otherwise they are filter feeders .
From aquarium observations, in which the green reef sea squirt slowly moved upwards on an aquarium pane, we know that they can change their location.
Reproduction
Reproduction takes place all year round. Internal fertilization takes place, the larvae first develop in the common cloacal space, and are then released into the open water to find a new location. During the short, free-swimming phase, the larvae carry Prochloron cyanobacteria with them in a hairy swelling on the back of the body. From the tadpole-like larvae, 9 mm long without a tail, a single zooid develops, which by budding other zooids and thus forms an animal stock over time. A large animal stock can divide and establish daughter colonies, which are initially still connected by mantle processes. Therefore, Green Reef Sea Squirts are usually found in dense groups of several colonies next to each other.
literature
- Harry Erhardt / Horst Moosleitner: Mergus Sea Water Atlas Volume 3 , Mergus-Verlag, Melle, 1997, ISBN 3-88244-103-8
- Harry Erhardt / Hans A. Baensch : Mergus Sea Water Atlas Volume 4 , Mergus-Verlag, Melle, 1998, ISBN 3-88244-023-6
- Helmut Schuhmacher / Johannes Hinterkircher: Niedere Meerestiere , BLV, 1996, ISBN 3-405-14854-5
- Svein A. Fossa / Alf Jacob Nilsen: Coral reef aquarium. Volume 6, Schmettkamp Verlag, 1998, ISBN 3-928819-18-6
