Starburst anemone
Image:The war between Anthopleura sola 1.jpg|thumb|In a California tide pool, Anthopleura sola fight for territory using their white stinging acrorhagi.
The starburst anemone or sunburst anemone is a species of sea anemone in the family Actiniidae. The sunburst anemone was formerly considered the solitary form of the common aggregating anemone, but was identified as a separate species in 2000.
Description
The sunburst anemone is a solitary anemone that averages but can grow up to wide, much larger than the aggregating anemone.The column is pale green to white in color and is twice as long as its width when extended. The column has numerous sticky protuberances arranged in vertical rows to which gravel and shell fragments adhere. The oral disc is radially striped and has five rings of thick, pointed feeding tentacles. Tentacles are pale with the tips colored in pink, blue or lavender.
The starburst anemone's tentacles and oral disk display varied color patterns. Their tentacle tips are pale because the anemones frequently shelter under rocks or in shaded areas, and this lack of light prevents the development of green pigments. Additionally, the striped patterns on the tentacles are a result of genetic differentiation.
Although morphologically similar to the Aggregating Anemone (Anthopleura elegantissima), the Sunburst Anemone can be distinguished by its solitary nature. A. elegantissima is highly clonal and is almost always found in dense groups of its clones, whereas A. sola is non-clonal and typically solitary.
It is differentiated from Anthopleura xanthogrammica by the coloration of the tentacle tips, striped oral disk, and vertical rows of verrucae.
The color of the anemone is partly caused by symbiotic Zooxanthellae in the gastrodermal layer. This species of anemone reproduces sexually.
Distribution and habitat
The sunburst anemone is found in the north west Pacific Ocean. In the United States it occurs between central California and Baja California. It lives in the lower intertidal zone in rocky habitats, often in the shelter of cracks and crevices. It also occurs in the subtidal, often in kelp forests, to depths of at least. When the tide is out it is often concealed by shell fragments and other particles that adhere to the column, which folds into an encrusted ball. The encrusted column may serve as camouflage from predators as well as protection from solar radiation and desiccation.Starburst anemone forms a symbiotic partnership with the dinoflagellate Breviolum muscatinei, a member of the family Symbiodiniaceae. This relationship is important to scientific interest as the geographic range of Anthopleura sola is expanding northward. As Sunburt anemone moves northward, it encounters Breviolum muscatinei, which has historically only formed partnerships with other anemone species, such as A. elegantissima and A. xanthogrammica.
Starburst anemone functions as a host in the symbiotic partnership with photosynthetic algae, primarily the dinoflagellate Breviolum muscatinei. The relationship is a nutritional exchange; the host receives photosynthetically produced sugars from the algae, while the algae receive metabolic nutrients and a protected location with access to sunlight.
However, this relationship can collapse under environmental stress, such as temperature changes, which leads to “bleaching” and the host can die. While the local population can adapt to develop resistance, this inherited adaptation only continues if the offspring live in a similar environment. Even though Sunburst anemone and Breviolum muscatinei form a partnership, each of them has its own separate life cycle with different patterns of reproduction and migration.
Anthopleura sola-encrusted.jpg|encrusted ball at low tide