There aren't many opportunities for humans to interact with octopuses and squids. These mysterious creatures of the sea are often depicted in cinema and literary works as ruthless predators of deep waters. Their strange appearance and behavior make us afraid of them. These strange creatures have fascinated people for centuries with their tentacles, suction cups and interesting mouths.
Why is Octopus Blood Blue?
One of the most interesting features of octopus is the colour of their blood. Although it may seem interesting to many people that the blood of octopus is blue, the reason for this is simply evolution. For example, people's blood is red, but one does not wonder why this is so. Octopuses have blue blood because there is a different protein called hemocyanin in the blood of these creatures. The main component in the blood of most living things is iron. Iron in the blood is found in the hemoglobin protein, which carries oxygen to organs and tissues. Iron oxidizes by binding to oxygen, causing the blood to be red in color. When iron oxidizes in nature, it undergoes the same color change and this is called rust. Hemoglobin is a highly effective oxygen transport protein. However, more primitive species such as octopus, squid and many other invertebrates contain copper as a binding mineral in their blood. Instead of hemoglobin, there is a different protein called hemocyanin in the blood of these creatures. When the copper in this protein binds to oxygen, it changes color and becomes blue.
The interesting part is that the hemocyanin protein also plays an important role in the adaptation of squid and octopuses to their environment. The pigment called hemocyanin, which gives the octopus's blood its blue colour, also enables it to survive in harsh conditions. Most squid and octopus live in extremely hot or cold environments, from temperatures as low as 28 degrees Fahrenheit (- 1.8 degrees) to high temperatures near the ocean's thermal vents, temperatures that would be fatal to many creatures. Since the copper atoms in hemocyanin have the ability to bond with a larger number of oxygen atoms, they can best meet the oxygen needs of their bodies. Even if there is no oxygen around them, they store plenty of oxygen in their blood. Researchers think that octopuses developed the blue blood adaptation because they are a species that cannot migrate far. Thus, it can survive even in harsh conditions and does not need to change its location. Octopuses need flexibility in thermoregulation and oxygen transport because they live near overheated air vents and Arctic waters, making the hemocyanin protein a more flexible option for their anatomy and specific needs.
Different Blood Colours Are Also Available
Creatures in nature cannot be classified only as those with blue and red blood. Because there are other blood colours besides these. For example, there is the Guinean green-blooded lizard of Papua New Guinea, which breaks down hemoglobin into its constituent parts. Prasinohaema, a vertebrate animal (a type of mountain lizard), has green blood. Prasinohaema carries hemoglobin in its blood like other vertebrates, but the high amount of biliverdin protein hides the red color of its blood, causing it to flow green. There are also some fish that live in extreme temperatures and completely purify the blood, lacking blood-borne protein carriers for oxygen. Believe it or not, there is more oxygen at the bottom of the ocean and fish do not need these colorful carriers because they directly absorb the oxygen from their environment. The blood of the horseshoe crab, which has lived since the age of dinosaurs, is also blue. The blood of some marine worms that contain hemerythrin protein may be purple in color.
