Green giant anemone
| Green giant anemone | ||||||||||||
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Green giant anemone ( Anthopleura xanthogrammica ) |
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| Anthopleura xanthogrammica | ||||||||||||
| Brandt , 1835 |
The green giant anemone ( Anthopleura xanthogrammica ) is one of the largest sea anemones (Actiniaria) and belongs to the class of flower animals (Anthozoa).
features
Green giant anemones live in symbiosis with zooxanthellae and zoochlorella (green algae ) , which give them their green color. Since they are carnivores, these algae have organic components that make them palatable to the giant green anemone. In caves they quickly lose their color and turn white. While they are lighter inside, the tentacles are dark to olive green to brown.
They reach a diameter of 10 to 25 cm and a body height of 7 to 25 cm and are therefore among the largest sea anemones. The tentacles are covered with thousands of stinging nematocytes . However, they are non-toxic to humans. Although they can move slowly on their suction cup, they usually stay on the same rocky spot for their entire life. When the sea subsides, they retract their tentacles and close to prevent them from drying out.
Occurrence
Green giant anemones are widespread in the northeastern Pacific from Alaska to Panama on stony coasts in the intertidal zone .
nutrition
Green giant anemones feed on peeled mussels , sea urchins , small fish and crabs . In many places, mussels make up a major part of the diet. The giant green anemone is one of the few predators of the sea snail Aplysia californica , the California sea hare . The prey is paralyzed with the nettle cells . Their small flagella carry the prey into the stomach cavity through the opening in the middle of the mouth disk. Once the food is digested , the excrement is excreted through the same opening. Despite the poisonous nettle cells, the hermit crab Pagurus samuelis lives together with the green sea anemones.
Enemies
Giant anemones are eaten by crabs , woodlice spiders (including Pycnogonum stearnsi ) and starfish (especially Dermasterias imbricata ). Important predators are various marine slugs , including some nudibranchs such as Aeolidia papillosa , which grazes the tentacles, and spiral staircases - in southern California and the like. a. Opalia borealis , Opalia chacei and Opalia funiculata , which drill their proboscis into the body of the sea anemone, and in the intertidal zone Epitonium tinctum , which also eats tentacles.
Reproduction
From late spring to summer, the males release sperm to stimulate the females to also release their eggs. The fertilization takes place in the water. They can also reproduce asexually, through budding , cell division, or wounds to the foot.
literature
- Hans A. Baensch / Robert A. Patzner: Mergus Sea Water Atlas Volume 5. Mergus-Verlag, Melle, ISBN 3-88244-115-1
Web links
Individual evidence
- ^ Lindsay R. Winkler, Bernard E. Tilton (1962): Predation on the California Sea Hare, Aplysia californica Cooper, by the Solitary Great Green Sea Anemone, Anthopleura xanthogrammica (Brandt), and the Effect of Sea Hare Toxin and Acetylcholine on Anemone Muscle . Pacific Science 16 (3), pp. 286-290.