The ocean is comprised of many different layers; understanding what those layers are and the physical causes of those layers is the first step in exploring that which takes up the majority of our planet.
There are three different factors that work in conjunction to determine the density of the water present in a given area, the temperature, the salinity, and the water pressure present (ONR, 2015). It is these different densities present within the ocean that serve to allow humans to demarcate certain levels within the ocean. There are three primary regions present within the oceans, divided into a total of five different layers (ONR, 2015; Knight, 2015). The top region of the ocean is identified as the surface mixed zone, whose temperature and salinity are able to change as a result of its contact with the air (ONR, 2015).
The next region is known as the transition zone, or pycnocline; density in this region does not change greatly, and this particular region serves to act as the dividing line between the surface and the bottom regions of the ocean itself (ONR, 2015). The final region is referred to as the deep zone; water here remains cold and dense and the pressure here is great (ONR, 2015). The layers of the ocean, in descending order are the epipelagic zone, mesopelagic zone, bathypelagic zone, abyssopelagic zone, and the hadalpelagic zone (Knight, 2015).
The hadalpelagic zone gets its name from hadal – meaning hell; this zone is hell-like not because it is hot, but rather the exact opposite. This zone is found most commonly in trenches and canyons, and consists of the very deepest parts of the ocean (Knight, 2015). The temperature of the water is barely above freezing and the pressure is “eight tons per square inch,” roughly the weight of “48 Boeing 747 jets” (Knight, 2015, p.1).
It is as a result of the conditions, where human life could not sustain, though life is possible, that the conditions are referred to being hellish; that and the fact that the zone starts at 6,000 meters below the surface and goes to the bottom of the oceans. Its close proximity to religious references of hell and the neigh unlivable conditions serve to give the zone its name. Understanding the ocean in all of its glory is the first step to gaining increased insight into the world around us.
- Knight, J. (2015). Layers of the Ocean – Deep Sea Creatures on Sea and Sky. Seasky.org. Retrieved 24 April 2015, from http://www.seasky.org/deep-sea/ocean-layers.html
- ONR. (2015). Ocean Water: Density. Retrieved 24 April 2015, from www.onr.navy.mil/focus/ocean/…/density1.htm