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Species of the month

Eastern Emerald Elysia

Some facts about this green sea slug:

Description:
Elysia chlorotica (common name the eastern emerald elysia) is a small-to-medium-sized species of green sea slug, a marine opisthobranch gastropod mollusc. This sea slug superficially resembles a nudibranch, yet it does not belong to that clade of gastropods. Instead it is a member of the clade Sacoglossa, the sap-sucking sea slugs. Some members of this group use chloroplasts from the algae they eat for photosynthesis, a phenomenon known as kleptoplasty. Elysia chlorotica is one of these "solar-powered sea slugs". It lives in a subcellular endosymbiotic relationship with chloroplasts of the marine heterokont alga Vaucheria litorea.
Elysia chlorotica feeds on the intertidal alga Vaucheria litorea. It punctures the algal cell wall with its radula, then holds the algal strand firmly in its mouth and sucks out the contents as from a straw. Instead of digesting the entire cell contents, or passing the contents through its gut unscathed, it retains only the chloroplasts, by storing them within its extensive digestive system. It then takes up the live chloroplasts into its own gut cells as organelles and maintains them alive and functional for many months. The acquisition of chloroplasts begins immediately following metamorphosis from the veliger stage when the juvenile sea slugs begin to feed on the Vaucheria litorea cells. Juvenile slugs are brown with red pigment spots until they feed upon the algae, at which point they become green. This is caused by the distribution of the chloroplasts throughout the extensively branched gut. At first the slug needs to feed continually on algae to retain the chloroplasts, but over time the chloroplasts become more stably incorporated into the cells of the gut enabling the slug to remain green without further feeding. Some Elysia chlorotica slugs have even been known to be able to use photosynthesis for up to a year after only a few feedings.quently endorsed by the World Health Assembly on 8 May 1980.