Due to antifreeze protein, the blood of fish living in Antarctic waters will not freeze, although the temperature is around 0°C. These protein prevent the water in the blood from turning into ice and damaging the cells.
Antarctic is a very desolate place. The temperature is far below the freezing point, and the wind is blowing, and no tree can be seen. It's a miracle that anything can survive there. What really puzzles me is how creatures as fragile as fish can survive there.
If you have raised goldfish, then you will know how sensitive you are to temperature changes. What makes fish so susceptible to changes? How do fish swimming in the cold waters of Antarctica survive?
Cold-blooded creature, we often hear the saying that fish are cold-blooded, but what does this mean? A cold-blooded creature is an animal whose body temperature depends on its surroundings. This can be seen in almost all fish, reptile and amphibian .
On the other hand, warm-blooded animals can maintain their body temperature. Most warm-blooded animals have little problem adapting to a range of temperatures. This is mainly found in mammals and birds. Some fish have adapted to the warm blood system, such as the Pacific bluefin tuna, which exhibits an automatic vein and vein heat exchange. A species of lunaria family found in Hawaii is actually a completely warm-blooded animal.
This is not the case with fish in the Antarctic ocean. They have the composition of cold-blooded animals, but have evolved an interesting adaptation.
This is an opaque fish, the only real warm-blooded fish.
The danger of freezing temperature, the blood must be kept flowing throughout the living animal's bodies. Blood transports oxygen and nutrients to various parts of our body, so what will happen to ordinary blood in the Antarctic region?
First of all, 90% of our blood is water. This means our blood will freeze in Antarctic waters. Due to the salt content in the ocean, the freezing temperature of the water drops to -1.9°C. This temperature below zero will cause the formation of ice crystals in the blood. When ice crystals form in our blood, they hurt all our cells, just like a delicate balloon that pokes our cells.
Cold-blooded animals like fish must find other ways to fight these frozen temperatures, because they cannot count on their own body temperature to save them.
So, how did this special fish overcome frost? Blood contains antifreeze blood!
Antifreeze blood refers to certain compounds that can be added to water to reduce its freezing temperature. A typical anti-freeze blood work is to prevent the formation of ice crystals.
In Arctic fish, these special compounds are antifreeze proteins in fish. They are produced like any other protein in the body.
Now, what are the functions of these proteins to prevent blood from freezing?
Oval ice fish, one of the many fishes containing antifreeze protein in the blood. When water compresses into a specific lattice , ice will form. This means that as the molecules get closer, water condenses, and as their intermolecular space decreases, water molecules attract each other more strongly, thus forming a lattice.
Antifreeze protein in fish blood enters these lattices and prevents them from connecting together. If crystals are prevented from connecting to each other, they cannot form ice in the blood. They cannot form ice crystals that are large enough to cause any damage to the body.
Interestingly, this is not the only place where we see this ability!
Antifreeze in nature, Antarctic fish are not the only organisms that have evolved this interesting adaptation, antifreeze proteins actually exist in many other organisms.
This adaptation can be seen in many primitive organisms, such as sea ice diatoms and certain bacteria, but it is also seen in more evolved organisms such as Snowmelli and even some beetles !
1Medicalworm beetle is another species with antifreeze protein in the blood
Interestingly, these adaptations evolved in different ways, but ultimately achieved the same results. In evolutionary studies, this phenomenon is called convergence evolution . Simply put, it's like many different routes on the map, ending with the same destination.
These antifreeze proteins are exciting, they may actually be useful to humans as well!
They can be used as applicants for cryopreservation when preserving tissues, especially in medicine. These compounds can be used as natural alternatives to existing antifreeze compounds that are toxic to the human body.
It can also be used in agriculture. Frost damage is a huge destructive factor for plants, so using these natural peptide compounds can help plants survive particularly harsh winters.
Exciting how unexpected discoveries in nature change our way of life!
