Do Jellyfish Breathe? (Respiratory Mechanism)

It is common knowledge that all animals need to engage in one form of respiration or another to stay alive. When you think of breathing in animals, the first organ that ordinarily comes to mind is the nose. But for jellyfishes, who strangely don’t have a nose, brain, or even heart, how do they ever manage to breathe?

Typical of scyphozoans, jellyfishes lack specialized organs like the nose or lungs for breathing. But they yet manage to breathe by physiologically adapting their skins to retain oxygen. The skin is particularly thin, allowing for direct oxygen absorption. Also, jellyfishes have their bodies equipped with gastrovascular cavities that transport oxygen and carbon dioxide all through their bodies.

Jellyfishes are some of the strangest and yet lovable creatures. Do jellyfishes have respiratory systems? Can a jellyfish survive without oxygen? Can a jellyfish breathe on land?

Read on to find the answers to these exciting questions.

How Do Jellyfishes Breathe?

Unlike humans and the generality of fishes, jellyfishes don’t have lungs or gills. Also lacking nostrils, the jellyfish is forced to maneuver its way to derive oxygen.

It responds by growing incredibly light skin. This skin can trap oxygen, suck it in and distribute it through the body.

This is even without the jellyfish having a heart that pumps blood through which oxygen is transported in most animals.

It would interest you to know that this process of breathing through the skin was first deployed by the earliest microbial organisms to populate our planet.

Specifically, this skin-optimized respiration – as seen in jellyfishes – has been used by microbial life forms some 2.8 billion years ago.

To fully examine how a jellyfish breathes, let us dig deeper into how this organism’s respiratory framework operates.

Do Jellyfish Have a Respiratory System?

Jellyfishes have a unique respiratory mechanism. In contrast to many fishes, they don’t have gills. But then jellyfishes need oxygen to survive, so they source their oxygen from the environment by diffusion.

The jellyfish’s metabolizing cells are stationed very close to the skin. This minimal distance separating the cells from the skin ensures that oxygen trapped by the skin can readily penetrate and be distributed to vital cells to sustain the jellyfish’s life functions.

Oxygen diffusion in the jellyfish is enhanced by its coelenteron. The coelenteron is the space filling up the interior of the jellyfish’s gut.

By the way, the jellyfish strangely has a 2-way gut. This means the same canal doubly fulfills the role of ingesting food and ejecting food.

Now, the jellyfish’s coelenteron has a unique shape that improves the gastrodermis’ (an inner tissue layer lining the jellyfish’s blind guts) surface-area-to-volume ratio.

This betters how well oxygen is diffused through the jellyfish’s inner tissues despite lacking gills.

For a creature as big as the jellyfish relying solely on oxygen diffusion, it wouldn’t have been able to survive if its respiratory system needed high oxygen content to keep it working.

Jellyfishes manage to thrive even with the relatively low amounts of oxygen collected from the air and diffused through its body. Fundamentally, jellyfishes have low-oxygen needs, thanks to their mesoglea.

The mesoglea is a noncellular tissue layer (sort of gelatinous) that connects the jellyfish’s gastrodermis to its outer epidermis.

The mesoglea upgrades the jellyfish’s tolerance to low-oxygen habitats. The mesoglea comprises nonliving materials that can store enough oxygen for the living tissues to utilize.

This way, jellyfish can survive in waters where other fishes would easily suffocate from lack of oxygen.

Can Jellyfish Live Without Oxygen?

While we have established that the jellyfish can survive in a habitat of extremely low oxygen, most jellyfishes essentially need (no matter how low) to stay alive.

If a jellyfish is totally denied oxygen for a very long time, it could die.

There is, however, a unique organism that closely mirrors jellyfishes that can survive without oxygen. A parasite called Henneguyasalminicola (H. salminicola) with no mitochondrial genome.

This parasite doesn’t breathe and is the first multicellular organism discovered by scientists to have zero oxygen dependency.

Of course, you should be curious how it manages this feat.

Tel Aviv University researchers found that this jellyfish-like organism can live its full life without oxygen by affixing itself to the interiors of the North Pacific salmon.

The inside of this salmon is well starved of oxygen. When the researchers investigated this parasite via fluorescence microscopy and deep sequencing, they found that it has no mitochondrial genome – typically used in metabolizing oxygen for body functioning.

To compensate for such asbent mitochondrial genome, the H. salminicola developed complex folds strongly identical to a jellyfish’s stinging cells.

With these cells, this parasite (sharing family with jellyfishes) can firmly hold to the insides of the North Pacific salmon.

Scientists envisage it can do without oxygen by leaching chemicals that supply energy and nourishment from the salmon.

Can Jellyfish Breathe on Land?

This is one question thrown at us often. With the jellyfish’s skin optimized to collect oxygen from water, can the jellyfish breathe on land?

The answer is NO. And we will explain.

Across the thousands of years our planet has seen, jellyfishes have consistently evolved their skins to collect oxygen from seawater.

Unlike humans (and your land pets) furnished with noses to collect atmospheric oxygen, jellyfishes can only collect aqueous oxygen.

This is, as said, via direct exchange of gas between the cells (positioned very close to the jellyfish’s exterior) and the surrounding water.

Rid of water (when on dry land) and left to derive its oxygen straight from the air, the jellyfish will start dying rapidly.

It is interesting to note that a jellyfish is 95% water. The other non-watery components are its pink rings (dedicated to reproductive duties) and its digestive system (commonly the brown materials located under the pink rings).

A jellyfish on a beach – typical of jellyfishes castaway by the retreating tide – begin to evaporate even before they severely suffocate.

This strange process is termed deliquescing and is accelerated when the sun shines vehemently.

With robust sunlight, the jellyfish would have evaporated within hours, leaving behind a faint imprint on the beach sand.

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