Environments of the Deep Sea


Deep Sea's Extreme Environments

The topic of the Deep sea has been on the spotlight these years. Well, then, what is the secret to it?

Deep Sea's Extreme Environments

From Ocean Exploration and Research

The key is the deep sea’s harsh environment. Phytoplankton cannot photosynthesize because light does not reach it, and it is very difficult to live because of the cold temperature and the extremely high water pressure due to its depth. But this is just the beginning. Highly acidic and alkaline hot water of several hundred degrees is ejected from the hydrothermal vent, and water rich in harmful substances is collected in the cold seep zone. These kinds of environments in which life is difficult to live is called the “extreme environment” in biology. Hydrothermal vents and cold seeps are one of the most extreme of the extreme environments. The deep sea itself is also classified as an extreme environment. Creatures live vigorously in such an extreme environment. Such organisms are called extremophiles. In these modern times, extreme environments are being enthusiastically studied in life science.

Why is the Deep Sea being studies so much?

 Esmeralda Bank Craterの蛸
From Ocean Exploration and Research
There are three main reasons for this. First, it teaches us the limits of survival conditions. This is also important information in the search for life in space, a topic you probably have heard somewhere in the media. This is because it provides us a clue as to what kind of environment a star may have to adopt life within. Secondly, it provides a clue to the mechanism of adaptation of life to an environment. For example, humans get burnt when they put their hands in hot water at 60 ° C, and normal octopus usually get boiled when it is put in boiling water at 100 ° C. These are because the proteins that make up humans and octopi get changed in the high heat. In short, if the octopus lives in an environment of 100 ° C and the protein of the octopus is denatured at 150 ° C instead of 100 ° C, the protein will not be destroyed even if the octopus is placed in boiling water. By comparing the proteins of organisms living in a high-temperature environment with those living in a normal temperature environment, it becomes a clue to understand the mechanism of proteins that do not break in a high-temperature environment. The last reason is its applicability to biotechnology. Compared to metal catalysts, catalytic protein enzymes that work under normal temperature and pressure have relatively fast reaction specificity and efficiency, and produce almost no by-products. However, common protein enzymes are less stable and break down quickly. That is one of the reasons why enzymes of microorganisms that live in high-temperature extreme environments, are highly stable and hard to break are beginning to be used for industrial purposes. For example, alkaline detergents use enzymes of microorganisms that live in the alkaline extreme environment. As you see, there are many cases in which research on extremophiles has been applied to biotechnology products, and those numbers are highly expected to increase in the future

How Organisms Evolve to Fit the Extreme Environments

From Ocean Exploration and Research

Even in harsh conditions, organisms evolve rapidly and vigilantly. The Pompeii worm in hydrothermal vents, is a good example. Pompeii worms carry bacterial armor that is very efficient at protecting them from deadly chemicals and heat. There are also lamellibrachia, also known as tube worms that protect themselves with specialized tubes and calyptogena, a species of giant white clam, protect their bodies with shells and obtain energy sources from symbiotic bacteria. Since hydrothermal vents and cold springs are separated from the surroundings, many endemic species can be found.


In recent years, technology has improved and the number of endemic species found is proportionally growing. However, humans only know less than 5% of the deep sea. In short, 95 percent of the deep sea is still full of mysteries. You may be thinking “It’s just a deep sea…” but, in reality, the deeps sea is a Jack-in-the-box waiting to be opened. It is full of surprises and probably, useful information that could possibly change our everyday lives. Extremophiles have been specialized in the environment for a daunting number of years. If you look closely at the specialized area, you can get various useful information. The protein enzymes explained earlier are already being used in industries. Pulp that makes better paper in the environment called "eco-pulp" and detergents that easily remove stains with a small amount are all active in the special features of extremophiles. Will the day when humans know everything about the deep sea come true? Will it take hundreds of years to elucidate? Perhaps not everything in the deep sea will ever be unraveled. However, I think that it is our mission to clarify as much as possible and pass it on to the future.