BY ANNELIESE MOLL
For the UAS Whalesong
Over the last week I read a couple of papers, referenced below, which I found particularly interesting. Bioluminescence and fluorescence are something most of us probably do not think about much if ever, however, both have many interesting aspects and are utilized by a wide variety of organisms.
Bioluminescence occurs within many species, most of which are marine, but not all are. An example of one such luminous organism are fireflies. There are also some other species including beetles, fungi, worms, and freshwater limpets. Other marine species range from bacteria to fish.
There are many uses for bioluminescence. These can range from interspecies communication, startling predators, counter illumination to lures. There are also some rather unusual uses that include acting as a burglar alarm and a sacrificial tag.
More specifically, the burglar alarm is an indirect effect that can cause other, larger predators to be  attracted to the site (Haddock 2010). This ultimately means bad news for the offender. Sacrificial tags are also interesting because when an organism is under attack or threat of an attack they can cause a certain part of their body to become luminescent, which enables them to escape with minimal damage.
Light produced through bioluminescence is through an oxidation reaction where the light emitting molecule, luciferin, which is combined with either luciferase or photoprotein. Some organisms can only produce light because of a symbiotic relationship with certain bacteria, however, most species who are bioluminescent are able to do alone.
In fluorescence the molecules do not actually produce light. They absorb photons and that excites electrons. That energy is released and light is produced. Green fluorescent proteins are also found in a large number of organisms. However, their ecological functions in any species still remain unclear. Some potential functions could include stress responses or to attract prey (Haddock and Dunn 2015). While the ecological functions are fully understood, humans have found a way to also utilize green florescent proteins. The protein has been able to be cloned and is now used in many different scientific applications. There is also a commercial aspect involving genetically modified organisms.
During the summer bioluminescence can be found here if you are able to find an area of water with little or no light pollution. All you have to do is stir the water, which will cause the phytoplankton to become luminous. I would definitely recommend trying this!

References:

Haddock, S. H., & Dunn, C. W. (2015). Fluorescent proteins function as a prey attractant: experimental evidence from the hydromedusa Olindias formosus and other marine organisms. Biology open, bio-012138.
Haddock, S. H., Moline, M. A., & Case, J. F. (2010). Bioluminescence in the sea. Marine Science, 2.