Revistes Catalanes amb Accés Obert (RACO)

Éssers que il·luminen: la bioluminescència

Begoña Vendrell Simón

Resum


If we looked at the Earth from space, we would clearly see that it orbits the Sun. Our planet receives energy from the Sun, and photoautotrophic organisms thriving on its surface can use this energy to convert inorganic into organic matter, thus acting as engines of trophic webs and ecosystems. From space, we would also see our planet covered by seawater. Considering that the mean depth of oceans is about 3000 m, we might then ask ourselves how the vastest and darkest ecosystem on Earth, the Ocean, works without directly receiving sunlight in most of its volume, as light only penetrates to a depth of about 200 m.
Looking at how marine organisms use light, we may discover different types of metabolisms, as well as ecological strategies used to see or not to be seen. Among all these, we find photosynthesis, sometimes also related to symbiotic relationships (vision) and the related cryptic and mimetic strategies, and also bioluminescence, which is the ability of organisms to produce cold light. Bioluminescence is the only source of light in the depths of the ocean, and is produced by various types of organisms, including bacteria, protists and a vast variety of marine animals. It is mostly due to the chemical oxidation of specific biomolecules, luciferins, and it may be used as a mechanism of defence, offence or communication among organisms. Although it is not an exclusively a marine phenomenon, in this article we will give an overview of what is currently known about bioluminescence in the sea.

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