Marine bacteria attack the plankton and fish, alluring light


29/02/2012

All is not gold that glitters. In the underwater world, this may just be the bacteria that use the properties of luminescence for the conquest of the living organism.

Many marine creatures can emit light, resulting from biochemical reactions. This phenomenon, known to science as bioluminescence, marked among some marine bacteria that light up as soon as the concentration reaches a certain level (a phenomenon called "quorum sensing") in organic particles floating in the ocean waters.

Although this phenomenon is well known to science, scientists long to determine the reason for the light micro-organisms. Now, however, in an article published in the National Academy of Sciences (PNAS), researchers from the University of Jerusalem have solved the riddle simple glow of marine bacteria. The explanation was presented by scientists of one phrase - "survival of the brightest."

The results showed that the light emitted by bacteria attracts predators, usually zooplankton, which absorb bacteria, but are not able to digest them. The bacteria remain lit inside the animal, and bright zooplankton, in turn, becomes an easy prey for their predators, ie fish that immediately notice it in the dark.

In the experiments conducted by researchers in the dark, it was revealed that the night the fish quickly detected and ate glowing zooplankton, whereas, zooplankton, swallowed bacteria that have been deprived of the ability to glow, did not attract the fish. Further study of nocturnal fish that ate zooplankton showed that the luminous bacteria survived and continued to emit light in the guts of fish. "To get the bacteria into the digestive system of fish - is like to get in" paradise "as it is the safest place, teeming with nutrients, and also a great vehicle in the vast ocean" - explained one of the researchers.

On the other hand, the actions of zooplankton attracted luminous bacteria, which they then swallow, it seems contrary to their own instincts of survival, as it increases the chances of being eaten by zooplankton, fish. The phenomenon of quorum sensing, which regulates bioluminescence bacteria may explain this contradiction, as the researchers noted. Zooplankton "knows" that the light in the water indicates the presence of large amounts of organic material, due to which bacteria develop.

In the dark depths of the ocean on large amounts of food is very limited, thus absorbing the glowing particles, zooplankton are at risk, not to die of hunger. In this environment, the probability of remaining hungry a lot more than the probability of becoming a victim of predatory fish, rarely appear here, as explained by the researchers.

Original: Physorg


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