Oceanography, the science of the oceans and seas, includes marine environments, coastal zone, management, fisher economics and marine pollution. The deep sea is the largest biosphere on earth canvasing relatively 79% of the earth’s solid surface. The deep sea, according to “The Blue Planet of Seas of Life”, is one of the largest unexplored ecosystems on the earth, beginning at 1,000 meters referred to as the bathypelagic zone and progressing to the hadal zone or the deep trenches.
The deep sea is considered an unfriendly climate where organisms are exposed to very bitter conditions.
Furthermore, the environmental component shifts drastically as one advances from the pelagic zone where photosynthesis occurs to the mesopelagic zone otherwise known as the “twilight” zone where sunlight is scarce and photosynthesis is non-existent. Equally, the last three zones namely, the bathypelagic zone, the abyssopelagic and finally the hadopelagic zones are all void of sunlight. Moreover, due to the absence of light, little oxygen, crushing pressures, extreme cold and lack of nutrients organisms have developed unique adaptations which are vital for their survival and reproduction.
The deep sea operates in darkness in reference to the absence of sunlight, forcing creatures to heavily depend on their senses in order to survive. In other words, light is a key component for locating mates, finding food and avoiding predators. Although this may be true, scientists have noted that many inhabitants of the deep, such as the Dragon fish and the Bomber Worm are able to carry out a chemical reaction which allows them to create light without heat- bioluminescence.
This ability enables them to attract mates, capture preys or protect themselves. Such an adaptation is uncommon among creatures living in the upper zones.
In like manner, deep sea creatures are threatened by intense pressure. As the pressure rises by 1 atmosphere per 10 meters in depth, the deep sea pressure can range from 20 atm to at least 1,100 atm. With such high pressures a fish’s body could be easily pulverized. In light of this fact, these fish have pressure resistant structures and piezolytes-small organic molecules that prevent distortion from high pressure. Correspondingly, deep waters can reach temperatures of -1 to approximately +4 degrees celsius, making it unbearably cold. Nevertheless, marine life has specially enhanced unsaturated membranes and “loose” flexible proteins, hence keeping them ‘liquid’ and preventing them from becoming stiff in the cold water.
By the same token, although much of the deep sea appears to have sufficient oxygen, there are some areas known as the ‘oxygen minimum zones’ where oxygen saturation is very low. Additionally, there are areas where there is no oxygen being circulated. One example is the bottom of the Mediterranean Sea. According to Robert Danovara, a researcher from the Polytechnic University of Marche claims that creatures like the loriciferans possess organelles that resemble hydrogenosomes, which some single-celled organisms use to produce energy-storing molecules anaerobically instead of mitochrondia, which rely on oxygen.
Identically, food scarcity in the deep waters is another grave factor that affect sea life at these depths. Uniquely, these creatures have adapted several intriguing techniques that allow feeding, thus increasing their survival. For instance, fish such as the ‘gulper eels’ is equipped with large mouths, huge hinged jaws and an expandable, large stomach that permits them to devour food in “bulk”. Others such as the anglerfish and the viper can be classified as “sitters”, who instead of swimming around in search of food lure their prey to them using bioluminescence. The hagfish, which is a jawless fish is able to bulldoze rapidly through fallen carcasses and quickly feast. Yet, som are known as ‘cruisers’ swimming slowly, listening and smelling for food. Still others such as the sea squirt and the sponges have evolved by sucking in unaware swimming animals through a large jaw-like siphon tubes and tiny pores respectively. Another sponge, the Chondrocladia, has a fascinating adaptation which enables it to pierce swimming preys with its sharp velcro-like spikes.
Equally important, many deep sea creatures have developed other adaptations which ensures their existence in spite of the hostile environment known as ‘home’. Body color has evolved among the deep sea animals to making it nearly impossible to be detected. For example, the hatchetfish reflects the light because of its silvery sides. Even the blacksmelt fish, along with some shrimps and squids, have black and red colors respectively, which makes them undetectable to their predators. Reproduction also plays a significant role in deep sea adaptations. Reproduction is vital for the preservation of a species. Despite the absence of light, deep sea creatures manage to reproduce successfully.
Some achieve this by use of their hooked teeth–attaching themselves to their mate. Both parties are satisfied with the male providing the sperm, while the female counterpart provides the food/nourishment.
The deep sea is a remarkable place which has eluded researchers for years and have captivated recent researchers’ attention. The “School of Thought” in the 1850’s was proposed by Edward Forbes, a man of esteemed knowledge, who claimed that life ceased to exist as we descend deeper. However, his theory was disproved by Michael and Georg Ossian Sars, who in 1864 showcased living sea lilies retrieved from 10,000 feet. With much attention to this finding, a stir created in the science community, which resulted in the British leading an expedition between 1872 and 1876. Other compelling evidences were produced in 1960 when Jacques Piccard, a Danish oceanographer pushed the envelope by going to the bottom of the Challenger Deep in his submersible–the Trieste. Later, in 2014, Jefferey Drazen also explored the Mariana French, where he realized that the creatures were very diverse.
All things considered, the deep sea is an extraordinary place which is home to a diverse plethora of creatures equipped with distinctive capabilities in order to survive and coexist with each other under severe circumstances. However, despite the advancement made in understanding the deep sea and its inhabitants, most of it still remains a mystery.