A strange visit
Une étrange visite
The deep sea, the largest and least explored ecosystem on Earth, is unique because of its permanent darkness, coldness, high pressure, and scarcity of carbon and energy to sustain life. Most of its biological activity relies on the arrival of carbon in the form of organic matter from surface waters. Many different types of organisms are capable of producing light through the chemical process of bioluminescence, which appears to be the most common form of communication in this remote realm.
From Wikipedia, the free encyclopedia :Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in the form of light emission. Fireflies, anglerfish, and other creatures produce the chemicals luciferin (a pigment) and luciferase (an enzyme). The luciferin reacts with oxygen to create light. The luciferase acts as a catalyst to speed up the reaction, which is sometimes mediated by cofactors such as calcium ions or ATP. The chemical reaction can occur either inside or outside the cell. In bacteria, the expression of genes related to bioluminescence is controlled by an operon called the Lux operon.Bioluminescence occurs in marine vertebrates and invertebrates, as well as microorganisms and terrestrial animals. Symbiotic organisms carried within larger organisms are also known to bioluminescence.
Example of other websites on bioluminescence:
Marine luminous bacteria are ecologically versatile and enjoy more than one life style, occurring as free living forms, epiphytes, saprophytes, parasites, symbionts in the light organs of fish and squid and commensals in the gut of various marine organisms (Ruby et al. 1980; Hastings 1983; Herring 1987).
The ecological role and physiological process of symbiotic luminous bacteria associated with marine macroorganisms are relatively well understood while little is known about planktonic luminous bacteria. For example, the presence of symbiotic bacteria in fish is of mutual benefit: the bacteria are supplied with nutrients and a protected environment whereas the fish is supplied with light (Dunlap & Kita-Tsukamoto 2006). In contrast, the reason why marine planktonic bacteria emit light is less obvious and several hypotheses have been proposed. For instance, luminous bacteria attached to sinking fecal pellets ejected by plankton might produce sufficient light to attract organisms to feed on the pellets and thus can recover favorable conditions (e.g. the gut of animals such as fish or zooplankton) thus enhancing the propagation of the bacteria (Nealson & Hastings 1979).ô Another hypothesis is that bioluminescence plays a continuous antioxidative role (Ruby 1996; Timmins et al. 2001; Szpilewska et al. 2003).
One of the objectives was to isolate and identify an ANTARES bioluminescent bacteria strain and to verify its capacity to growth and emit light under high-pressure conditions. For this purpose we have developed a new hyperbaric system able to measure both luminescence and growth of bacteria under high-pressure conditions (schematic view).
We have used this strain to investigate the effect of hydrostatic pressure on bioluminescence by developing a new high-pressure apparatus. First assays showed that bioluminescence intensity of Photobacterium phosphoreum strain ANT-2200 was 5 times higher at 22 MPa than at 0.1 MPa (atmospheric pressure) (figures).
Contact person: C. Tamburini (firstname.lastname@example.org)
Reference: Al Ali B., Garel M., Cuny P., Miquel J.-C., Toubal T., Robert* A., Tamburini C., 2010. Luminous bacteria in the deep-sea waters near the ANTARES underwater neutrino telescope (Mediterranean Sea). Chemistry and Ecology 26 (1), 57-72. Abstract. [Journal home page]
Author : Thierry Stolarczyk