Milky Sea

Bacteria A peroxide intermediate, quorum sensing and milky seas. Although the luciferin-luciferase test in bacterial extracts was negative, Strehler16 discovered that light emission in extracts could be obtained by adding reduced pyridine nucleotide, underlining the fact that bioluminescence is not a phenomenon separate... 

Because the emission is continuous it had been speculated, and many scientists believed, that luminous bacteria might be responsible. But, if so, how might the auto inducer concentrations needed be achieved The answer to this is not yet known, nor is it certain that the light is actually due to luminous bacteria of the kind already cultured. But a clue comes from reports of merchant sailors, who from time to time reported what they saw in a bucket of water from the milky sea. A typical description was that the water ... contains thousands of very thin lines of light. 

Fig. 7. Bioluminescence of milky seas recorded by satellite imaging for 3 consecutive nights. Raw data, A,B,C with background subtracted, D,E,F. Left,...

Herring P, Watson M. Milky seas a bioluminescent puzzle. Marine Observer 1993 63 22-30. 

Miller S, Haddock S, Elvidge C, Lee T. Detection of a bioluminescent milky sea from space. Proc Natl Acad Sci 2005 102 14181-4. 

Nealson K, Hastings JW. Quorum sensing on a global scale massive numbers of bioluminescent bacteria make milky seas. Appl Environ Microbiol 2006 72 2295-7. 

There is also another defensive secretion that sea hares release less readily than ink. This is a milky white liquid called opaline, so viscous that it can be stretched out through the air into a long string. For sea hares, opaline is what is known as a defining characteristic, because all sea hares emit opaline whereas no other species are known to do so. In spite of its defining role, opaline remains poorly understood. It contains proteins and perhaps components derived from the animals diet the evidence here is in dispute. A sea hare releases opaline less readily than ink but seems to do so as a second response to serious predatory assaults. When touched by a sea anemone s tentacles, a sea hare discharges a shot of opaline, which causes the anemone s tentacles to contract. No one yet understands how opaline deters predators or what chemicals are responsible for its activity. 

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