Snakelocks' Symbiosis

Snakelocks Anemone, Anemonia viridis

The Snakelocks Anemone (Anemonia viridis) is one of the more common anemone species to be found on the Irish shore line, and also one of the more conspicuous due to its inability, unlike some other anemone species, to withdraw its tentacles (1). These are the same colour as the animals body, which varies from a dull brown to a vibrant green, with purple tips. Brighter, greener coloured animals are found in shallower waters than the duller ones due to the presence in the endodermal layer of the anemone of the unicellular dinoflagellate, Symbiodinium sp., commonly known as zooxanthellae, that forms a symbiotic relationship with A. viridis (2). To provide its symbiont partner with CO₂ for photosynthesis, A. viridis absorbs inorganic carbon from seawater (3). Algal-animal associations such as this are common among cnidarians in the tropics, but less so at higher latitudes. Of the c. 80 species of anemones reported in Irish waters, only three, including A. viridis, form such relationships (4).

References:

1. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 174
2. Richier et al., 2006. FEBS Journal 273 pp. 4186-4198
3. Furla and Allemand, 2000. Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology 126 Supplement 1 p. 53
4. Bythell et al., 1997. Proceedings of the Royal Society of London B: Biol Sciences 264 pp. 1277-1282