Oceanography: An Introduction To The Marine Environment

Much of the ocean has still been unexplored, but the parts that we have explored have allowed us to see something nearly unbelievable for the first time: fish that naturally light up! In fact, many different types of creatures that live in the water light up: squid, eel, jellyfish, which can be seen to the right in figure one, and many various species of fish have the ability to do such. The ability, called bioluminescence, is defined as “ the emission of light from living organisms”, according to Merriam-Webster. More informally, it is considered the ability where a creature, which can live either on or off-land, can produce their own light. Some insects, such as glow worms, can make themselves light up at will. A more common example of …show more content…
Richard Davis, the author of Oceanography: An Introduction to the Marine Environment, says that the ocean is divided into three layers, and all are separated by the amount of light that travels through them. The top layer is called the sunlight, or euphotic, zone which is the top of the ocean, what we see without having any special submarine gear, to about 200 meters. In many situations, sunlight does not go beyond this level. Below that is the twilight, or dystophic, zone, which travels from two hundred to approximately one thousand meters below sea level. At that depth, there is so little light that photosynthesis is impossible. Now, from one thousand meters to the absolute bottom of the ocean is formally considered the aphotic zone, but informally called the “midnight zone”. In that zone, which makes up the large majority of the oceans, there is absolutely no light. The midnight zone is a pitch black area. Without any light there, it is impossible to see, so many of the creatures residing there have adapted to find creative ways to catch …show more content…
However, the light that they are going towards turns out to be the end of a lure on an angler fish, which then attempts to eat them. Thankfully, they get away unharmed. You can see a still from the scene in figure 3, shown above. Glow worms and fireflies also carry the same ability, as well. However, not every creature that glows or “lights up” produces the light themselves; some creatures, such as sea turtles, reflect the light back. Some species of coral translate ultraviolet waves into visible light waves, which can make it appear that they produce the light themselves, although they did not. In order to be bioluminescent, creatures must be able to produce the light naturally, either through the process using luciferins and releasing energy from molecules, or by lighting up using a combination of