Elysia chlorotica is a species of marine mollusk commonly called "Emerald Green Sea Slug" or simply "Eastern Emerald". It belongs to the Placobranchidae family, known for their ability to establish an endosymbiosis relationship with an alga (Vaucheria litorea) to photosynthesize food.
E. chlorotica feeds on the algae, partially digesting it, and keeping the chloroplasts viable, where a phenomenon called kleptoplasty occurs, which allows the body to take advantage of the autotrophic capacity of the plastids.
By Karen N. Pelletreau et al., via Wikimedia Commons
In this way, it can survive for months without feeding, feeding only on sunlight thanks to the ability to synthesize chlorophyll through chloroplasts incorporated into the cytoplasm of the cells of its body.
This species of slug is located on the littoral coasts of North America, between Florida and Nova Scotia. It was initially described by August Addison Gould in 1870, however, it was in 2010 when researchers from the University of South Florida led by the Ph.D. Sidney K. Pierce, completed research on the molecular biology of the species and its endosymbiotic relationship with the filamentous chromophytic alga V. litorea.
characteristics
Due to its physiological characteristics, it was believed that it was one of the first members of the animal kingdom to produce chlorophyll, a green pigment present in plants, algae and bacteria, which facilitates the photosynthesis process.
Members of this species resemble a broad, wavy green leaf with a snail head. During their 9-10 month lifespan, they can grow to a length of 2-5 cm.
In its juvenile phase, it has a grayish-brown color with reddish spots, however, as it feeds on the V. litorea algae, it acquires a bright green hue in its adult phase due to the concentration of chloroplasts in its tissues.
In nature, the adult feeds on algae only occasionally, obtaining metabolic energy from the photosynthetic activity of intracellular chloroplasts.
The emerald green slug survives in aquariums for 8-9 months without feeding, only assimilating energy from sunlight, a period of time similar to its life cycle in nature.
The association of endosymbiosis is not inherited from one generation to another, since the plastids have not been located in the eggs of the species. In contrast, chloroplast endosymbiosis is renewed with each new generation of photosynthetic slugs.
Taxonomy
However, due to its ability to survive only by obtaining energy through the photosynthetic process derived from chloroplasts that it stores in the cells of its body, it is a species of high scientific and economic value.
Discovering the components and processes that this species has in its genome is the key to generating green energy without the direct intervention of plants.
References
- Chan, CX, Vaysberg, P., Price, DC, Pelletreau, KN, Rumpho, ME, & Bhattacharya, D. (2018). Active host response to algal symbionts in the sea slug Elysia chlorotica. Molecular biology and evolution, 35 (7), 1706-1711.
- Woman, CV, Andrews, DL, Manhart, JR, Pierce, SK, & Rumpho, ME (1996). Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica. Proceedings of the National Academy of Sciences, 93 (22), 12333-12338.
- Rafferty John P. Elysia chlorotica - Sea Slug. Encyclopedia Britannica. Recovered at: britannica.com
- Sidney K. Pierce. (2015) Cellular physiology and biochemistry. University of South Florida. College of Arts and Sciences. Recovered at: Biology.usf.edu
- Taxonomic Serial No.: 77940 Elysia chlorotica Gould, 1870. ITIS Report. Recovered at: itis.gov