Algae bioluminescent

Ecotoxicity assessment of water samples was carried out, in parallel to chemical analysis, using three standardized bioassays based on the micro-crustacean Daphnia magna, the algae Pseudokirchneriella subcapitata, and the bioluminescent bacteria Vibrio fischeri. 

Symbiosis with algae and bacteria (including Cyanobacteria) is widespread in ascidians and is responsible for coloration as well as defensive metabolites, which may themselves be colorful. Symbiotic bacteria are also responsible for the (probably defensive) bioluminescence of their pelagic relatives, the Thaliacea.96 Brooding of the young tadpole larva may facilitate the transfer of symbionts from one generation to the next. Many of the metabolites in ascidians are quite similar to those known to be produced by bacteria, and the taxonomic distribution of the metabolites in the animals tends to confirm this.97 Others, however, are evidently produced by the tunicates themselves. 

For example, the unicellular marine alga Gonyaulax undergoes dramatic circadian changes in the intensity of its bioluminescence. Over one 10-day period the luminescence peaked every 22.99 0.01 hours. ... 

Nakamura, H., Ohtoshi, M., Sampei, O., Akashi, Y, and Murai, A. (1992) Synthesis and absolute configuration of (+)-gonyauhne a modulating substance of bioluminescent circadian rhythm in the unicellular alga Gonyaulax polyedra. Tetrahedron Lett., 33, 2821-2822. 

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