jellyfish essay in english

Jellyfish have drifted along on ocean currents for millions of years, even before dinosaurs lived on the Earth. The jellylike creatures pulse along on ocean currents and are abundant in cold and warm ocean water, in deep water, and along coastlines. But despite their name, jellyfish aren't actually fish—they're invertebrates, or animals with no backbones.

Jellyfish have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them. Inside their bell-shaped body is an opening that is its mouth. They eat and discard waste from this opening.

As jellyfish squirt water from their mouths they are propelled forward. Tentacles hang down from the smooth baglike body and sting their prey.

Jellyfish stings can be painful to humans and sometimes very dangerous. But jellyfish don't purposely attack humans. Most stings occur when people accidentally touch a jellyfish, but if the sting is from a dangerous species, it can be deadly. Jellyfish digest their food very quickly. They wouldn't be able to float if they had to carry a large, undigested meal around.

They dine on fish , shrimp, crabs and tiny plants. Sea turtles relish the taste of jellyfish. Some jellyfish are clear, but others are in vibrant colors such as pink, yellow, blue, and purple, and often are luminescent. The Chinese have fished jellyfish for 1,700 years. They are considered a delicacy and are used in Chinese medicine.

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Jellyfish: our complex relationship with the oceans’  anti-heroes

PhD Candidate, Geography, Queen Mary University of London

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Matthew Beach receives funding from Queen Mary, University of London. He has also previously received funding from the Royal Geographical Society (with the Institute of British Geographers).

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Ding! The courier hands me an unassuming brown box with “live animals” plastered on the side. I begin carefully unboxing. The cardboard exterior gives way to a white polystyrene clamshell, cloistering a pearly sphere-shaped, water-filled bag. Lightly pulsing, I spot them: three cannonball jellyfish ( Stomolophus meleagris ). Each the size of a 50-pence coin.

After months of waiting, my first gelatinous companions had arrived and I was finally ready to begin my research on human connections with jellyfish.

Cannonball jellyfish are an unusual pet choice . Whether stinging beachgoers, clogging power station intake pipes, or outcompeting more popular ocean wildlife, jellyfish are often labelled nuisances .

Despite their poor press, they have a growing community of admirers. Thousands of people drift to aquariums each year to admire jellyfish. Darting around and bumping into one another, tentacles circling or gently pulsing they inspire delight in their guests. The Californian Monterey Bay Aquarium’s Jellyfish: Living Art was the organisation’s most popular and long-running exhibit since opening in 1984.

Jellyfish not only have the ability to captivate us. It may also benefit our health . A study has shown eating cannonball jellyfish, for example, can reduce the effects of arthritis – albeit so far only in a small group of rats.

A biological wonder

Perhaps more importantly, however, we can learn a lot from studying the incredible biology of jellyfish. For example, immortal jellyfish ( Turritopsis dohrnii ) sidestep the ageing process by reverting to their polyp stage.

Crystal jellies’ ( Aequorea victoria ) green fluorescent protein (GFP), found in organs within the animal’s bell, allows scientists to study gene expression. Gene expression is the instruction manual DNA follows, for example, to become proteins. This process can be quite complex and difficult to follow. But the GFP lights up under ultraviolet light, which helps scientists map the different processes a cell goes through as it follows DNA instructions.

Jellyfish deserve more of the public’s attention. They are a major player in the marine food web and have complex relationships with other wildlife. For example, cannonball jellyfish have a fascinating relationship with young spider crabs ( Libinia spp. ) that live inside their bells. This gives the crabs security and research suggests jellyfish hosting crabs grow larger than those without, but it’s not clear why.

Some scientists say jellyfish are climate-change survivors , which they don’t mean as a compliment. Despite rising temperatures, they sometimes “ jellify ” the ocean because of their sudden population “blooms”. However, they have their own climate-change-related problems .

For example, temperature increases in Palau’s Jellyfish Lake in the South Pacific have been linked to the disappearance of golden jellyfish ( Mastigias papua ). Jellyfish blooms are also often followed by crashes in their populations, which are caused by several overlapping factors such as food shortage, predation, parasites, disease, weather and getting stranded on beaches.

Sea curiosities

There are so many reasons humans should make an effort to understand jellyfish better. Research suggests ocean literacy is best cultivated through hands-on experience and personal interactions . But the technology aquariums use to bring jellyfish to the masses limit how involved audiences can be with the animals.

Although scientists have argued technology can damage people’s relationships with other animals, it can help us reconnect with our environment too.

Because jellyfish are 95% water , they are extremely sensitive to their surroundings. Most kit tanks (often referred to as nano aquariums ) hold a small water volume, which makes it difficult to maintain the right conditions such as pH, ammonia levels and temperature.

Bacteria must be introduced into the tank to control jellyfish waste (ammonia) by converting it into nitrite and then nitrate. These bacteria are similar to the oxygen-producing microbes in the ocean that form the basis of all ocean food webs , and help maintain the ocean cycle . The nitrate is removed by replacing small amounts of aquarium water with purified salt water.

As I discovered, if these conditions are not maintained, the jellyfish can suffer from bell holes (small circular tears in jellyfishes’ bells) and eversion (when the outer portion of the bell inverts). When aquarium jellyfish suffer eversion , high water temperature is often the culprit. Learning how to care for jellyfish in these kits is learning about their complex relationships to our oceans.

The closer we feel to our environment, the more likely we are to fight to protect it. So next time you visit the seaside or your local aquarium, try to slow down, absorb the experience and see if you can learn something new about jellyfish and wider ocean wildlife.

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Jellyfish Facts!

Join us as we travel the oceans far and wide with these electric jellyfish facts.

Join us as we travel the oceans far and wide with these electric jellyfish facts !

Fast jellyfish facts

Phylum : Cnidaria Class : Scyphozoa Classification : Invertebrate IUCN status : Not evaluated Lifespan (in wild) : One year Weight : Up to 2kg Body size : 2cm to 2m Top speed : 8km/h Diet : Fish, shrimp, crabs, tiny plants and even other species of jellyfish Habitat : Oceans Range :

Jellyfish have been around for millions of years , even before dinosaurs lived on the Earth. Pulsing along on our ocean currents, these jelly-like creatures can be found in waters both cold and warm, deep and shallow and along coastlines, too. Some jellyfish are clear, but others are vibrant colours of pink, yellow, blue and purple. They can be bioluminescent , too, which means they produce their own light!

Jellyfish have no brain, heart, bones or eyes. They are made up of a smooth, bag-like body and tentacles armed with tiny, stinging cells. These incredible invertebrates use their stinging tentacles to stun or paralyse prey before gobbling it up.

The jellyfish’s mouth is found in the centre of its body. From this small opening it both eats and discards waste. And it serves another purpose, too – by squirting a jet of water from its mouth, the jellyfish can propel forward! Cool, eh?

Jellyfish digest their food, which consists of fish, shrimp, crabs and tiny plants, very quickly. If they didn’t, they wouldn’t be able to float, being weighed down by the large, undigested grub in their body.

The jellyfish itself provides a tasty meal for other ocean creatures, particularly sea turtles , who like to guzzle them up regularly. In some cultures around the world, people eat jellyfish, too. In China, they are considered a delicacy, and are also used in Chinese medicine.

Jellyfish stings can be painful to humans and, from certain species, they can even be deadly. Although these magnificent marine creatures don’t purposely attack humans, most stings occur when people accidentally touch a jellyfish.

Picture credits Bioflourescent jellyfish: Getty Images UK. Close-up of purple jellyfish: Bruce H. Obison. Jellyfish with long tentacles: Natursports, Dreamstime. Yellow jellyfish: Tim Hester, Dreamstime. Map showing jellyfish distribution: National Geographic Maps. 

What did you make of our jellyfish facts leave a comment below and let us know, leave a comment.

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jellyfishes are amazing

Wow great thank you so much!

Jellyfishes are cool

jellyfish are awesomly bad animals

there is a type of jelly fish that lives forever. Its called the immortal jellyfish!

Jellyfish are amazing and awesome. I liked the pictures

It was very informative about how the magnificent live , eat and there body structure

Great facts

It was interesting

I'm so excited!

I don’t know what you think about jellyfish

Nice to know

I learnt alot of things about jellyfish on this website great job keep it up

i like this web but it needs on the anamils one it needs the crok one on this

They are so cool

Doing project needed info thanks

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Jellyfish are the coolest

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LIVING ELECTRICITY!!!!!!!

i love jellyfish they are so cool

interesting

This information is very useful.This website is also very useful.Thank you 'NATIONAL GEOGRAPHY KIDS'

love these jellyfish just didn`t like it when i got stung in India .

I think the Jellyfish facts were very informative and it was just what I was looking for. Thank you.:)

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i think the jellyfish article was cool and when I went to the beach I saw a huge jellyfish!

Very very cool

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Jellyfish Facts: Habitat, Behavior, Diet

Scientific Name: Cnidarians; scyphozoans, cubozoans and hydrozoans

Mint Images / Getty Images

• Marine Life Profiles
• Marine Habitat Profiles
• Habitat Profiles

Description

Reproduction and offspring, humans and jellyfish.

• B.S., Cornell University

Among the most extraordinary animals on earth, jellyfish ( Cnidarians, scyphozoans, cubozoans , and hydrozoans ) are also some of the most ancient, with an evolutionary history stretching back for hundreds of millions of years. Found in all oceans of the world, jellies are made up of 90 to 95 percent water, compared to 60 percent for humans.

Fast Facts: Jellyfish

• Scientific Name: Cnidarian; scyphozoan, cubozoan, and hydrozoan
• Common Name: Jellyfish, jellies
• Basic Animal Group: Invertebrate
• Size: Bell diameter of two-tenths of an inch to over six and a half feet
• Weight: Under an ounce to 440 pounds
• Lifespan: Vary between a few hours to a few years
• Diet:  Carnivore, Herbivore
• Habitat: Oceans throughout the world
• Population: Unknown
• Conservation Status: Not Evaluated

Named after the Greek word for "sea nettle," cnidarians are marine animals characterized by their jelly-like bodies, their radial symmetry, and their "cnidocytes"—cells on their tentacles that literally explode when stimulated by prey. There are about 10,000 cnidarian species, roughly half of which are anthozoans (a family that includes corals and sea anemones); the other half are scyphozoans, cubozoans, and hydrozoans (what most people refer to when they use the word "jellyfish"). Cnidarians are among the oldest animals on earth: Their fossil record stretches back for almost 600 million years.

Jellyfish come in a wide variety of shapes and sizes. The largest is the lion's mane jellyfish ( Cyanea capillata ), which can have a bell over six and a half feet in diameter and weigh up to 440 pounds; the smallest is the Irukandji jellyfish, several species of dangerous jellyfishes found in tropical waters, which measure only about two-tenths of an inch and weigh well under a tenth of an ounce.

Jellyfish lack a central nervous system, a circulatory system, and a respiratory system . Compared to vertebrate animals, they are extremely simple organisms, characterized mainly by their undulating bells (which contain their stomachs) and their dangling, cnidocyte-spangled tentacles. Their nearly organless bodies consist of just three layers—the outer epidermis, the middle mesoglea, and the inner gastrodermis. Water makes up 95 to 98 percent of their total bulk, compared to about 60 percent for the average human being.

Jellyfish are equipped with hydrostatic skeletons, which sound like they might have been invented by Iron Man, but are actually an innovation that evolution hit on hundreds of millions of years ago. Essentially, the bell of a jellyfish is a fluid-filled cavity surrounded by circular muscles; the jelly contracts its muscles, squirting water in the opposite direction from where it wishes to go. Jellyfish aren't the only animals to possess hydrostatic skeletons; they can also be found in starfish , earthworms, and various other invertebrates. Jellies can also move along ocean currents, thus sparing themselves the effort of undulating their bells.

Weirdly, box jellies, or cubozoans, are equipped with as many as two dozen eyes—not primitive, light-sensing patches of cells, as in some other marine invertebrates, but true eyeballs composed of lenses, retinas, and corneas. These eyes are paired around the circumference of their bells, one pointing upward, one pointing downward—this gives some box jellies a 360-degree range of vision, the most sophisticated visual sensing apparatus in the animal kingdom. Of course, these eyes are used to detect prey and avoid predators, but their main function is to keep the box jelly properly oriented in the water.

Scyphozoans, or "true jellies," and cubozoans, or "box jellies," are the two classes of cnidarians comprising the classic jellyfish; the main difference between them is that cubozoans have boxier-looking bells than scyphozoans and are slightly faster. There are also hydrozoans (most species of which never got around to forming bells and instead remain in polyp form) and staurozoans, or stalked jellyfish, which are attached to the seafloor. (Scyphozoans, cubozoans, hydrozoans, and staurozoans are all classes of medusozoans, a clade of invertebrates directly under the cnidarian order.)

Most jellyfish eat fish eggs, plankton, and fish larvae, converting them to energy in an alarming pattern known as an energy-loss pathway. That kind of pathway consumes energy that would otherwise be used by forage fish who can be eaten by top-level consumers. Instead, that energy is being communicated to animals which eat jellyfish, not part of the higher food chain.

Other species, like upside-down jellies ( Cassiopea species) and Australian Spotted Jellyfish ( Phyllorhiza punctata ), have symbiotic relationships with algae (zooxanthellae), and they obtain enough carbohydrates from them to not need additional food sources. 

Jellyfish practice what is called vertical migration, arising from the ocean depths to the surface in large aggregations known as blooms. In general, they bloom in the spring, reproduce in the summer, and die off in the fall. But different species have different patterns; some migrate once or twice a day, and some migrate horizontally following the sun. The jellies most injurious to humans, the Irukandji species, undergo seasonal migrations which bring them into contact with swimmers in the tropics.

Jellyfish spend all of their time is seeking food, escaping predators, or finding a mate—some set a trap with their tentacles arranged in a spiral pattern, an impenetrable curtain for their prey, or array their tentacles in a big field around their bodies. Others simply drift or swim slowly, dragging their tentacles behind them like a trawler net. 

Some species are pleustonic, meaning they live at the air/water interface year round. Those include the sailing jellies, like the Portuguese man-of-war, the Blue Bottle, and the By-the-Wind Sailor Jelly ( Velella vellal ), which has an oblong blue raft and a silvery vertical sail.

Like most invertebrate animals , jellyfish have very short lifespans: Some small species live for only a few hours, while the largest varieties, like the lion's mane jellyfish, may survive for a few years. Controversially, one Japanese scientist claims that the jellyfish species Turritopsis dornii is effectively immortal: Full-grown individuals have the ability to revert back to the polyp stage, and thus, theoretically, can cycle endlessly from adult to juvenile form. Unfortunately, this behavior has only been observed in the laboratory, and T. dornii can easily die in many other ways (such as being eaten by predators or washing up on the beach).

Jellyfish hatch from eggs which are fertilized by males after females expel the eggs into the water. What emerges from the egg is a free-swimming planula, which looks a bit like a giant paramecium. The planula soon attaches itself to a firm surface (the sea floor, a rock, even the side of a fish) and grows into a stalked polyp reminiscent of a scaled-down coral or anemone. Finally, after months or even years, the polyp launches itself off its perch and becomes an ephyra (for all intents and purposes, a juvenile jellyfish), and then grows to its full size as an adult jelly.

People worry about black widow spiders and rattlesnakes, but pound for pound, the most dangerous animal on earth may be the sea wasp ( Chironex fleckeri ). The biggest of all box jellies—its bell is about the size of a basketball and its tentacles are up to 10 feet long—the sea wasp prowls the waters of Australia and southeast Asia, and its sting is known to have killed at least 60 people over the last century. Just grazing a sea wasp's tentacles will produce excruciating pain, and if contact is widespread and prolonged, a human adult can die in as little as two to five minutes.

Most poisonous animals deliver their venom by biting—but not jellyfish (and other cnidarians), which have evolved specialized structures called nematocysts. There are thousands of nematocysts in each of the thousands of cnidocytes on a jellyfish's tentacles; when stimulated, they build up an internal pressure of over 2,000 pounds per square inch and explode, piercing the skin of the unfortunate victim and delivering thousands of tiny doses of venom. So potent are nematocysts that they can be activated even when a jellyfish is beached or dying, which accounts for incidents where dozens of people are stung by a single, seemingly expired jelly.

Jellyfish are prey for sea turtles , crabs , fish, dolphins , and terrestrial animals: There are some 124 fish species and 34 other species that are reported to feed either occasionally or mainly on jellyfish. Jellyfish often establish symbiotic or parasitic relationships with other species—the parasitic ones are almost always detrimental to the jellyfish.

Many species—sea anemones, brittle stars , gooseneck barnacles, lobster larvae and fish—hitch rides on jellyfish, finding safety from predators in the folds. Octopuses are known to use jellyfish tentacle fragments on sucker arms as added defensive/offensive weaponry, and dolphins tend to treat some species like underwater frisbees . Jellyfish have been considered a delicacy for human diets since at least 300 CE in China. Today, fisheries raising jellyfish for food exist in 15 countries. 

But jellyfish may have the last laugh. Far from being a threatened species, jellyfish are on the increase, moving into habitats that have been damaged or destroyed for other marine creatures. Increased blooms can have negative impacts on human economic activities, clogging cooling water intakes at coastal power plants, bursting fishing nets and contaminating catches, killing off fish farms, reducing commercial fish abundance through competition, and interfering with fisheries and tourism. The primary causes for habitat destruction are human over-fishing and climate change, so the reason for the uptick in jellyfish blooms can be assigned to human interference.

• Chiaverano, Luciano M., et al. " Evaluating the Role of Large Jellyfish and Forage Fishes as Energy Pathways, and Their Interplay with Fisheries, in the Northern Humboldt Current System ." Progress in Oceanography 164 (2018): 28–36. Print.
• Dong, Zhijun. " Chapter 8 - Blooms of the Moon Jellyfish Aurelia: Causes, Consequences and Controls ." World Seas: An Environmental Evaluation (Second Edition). Ed. Sheppard, Charles: Academic Press, 2019. 163–71. Print.
• Gershwin, Lisa-ann. "Jellyfish: A Natural History." Chicago: University of Chicago Press, 2016.
• Hays, Graeme C., Thomas K. Doyle, and Jonathan D. R. Houghton. " A Paradigm Shift in the Trophic Importance of Jellyfish? " Trends in Ecology & Evolution 33.11 (2018): 874–84. Print.
• Richardson, Anthony J., et al. " The Jellyfish Joyride: Causes, Consequences and Management Responses to a More Gelatinous Future ." Trends in Ecology & Evolution 24.6 (2009): 312–22. Print.
• Shikina, Shinya, and Ching-Fong Chang. " Cnidaria ." Encyclopedia of Reproduction (Second Edition). Ed. Skinner, Michael K. Oxford: Academic Press, 2018. 491–97. Print.
• Overview of Cnidarians
• Cnidarian Facts: Corals, Jellyfish, Sea Anemones, and Hydrozoans
• Identification of Jellyfish and Jelly-like Animals
• Invertebrate Photo Gallery
• Box Jellyfish Facts
• A Guide to the Cnidarians
• Treating Jellyfish Stings and Man-o-War Stings
• Moon Jellyfish Facts
• Animals of Australia's Great Barrier Reef
• Lion's Mane Jellyfish
• Shark Facts: Habitat, Behavior, Diet
• 31 Different Groups of Invertebrates
• Cannonball Jellyfish Facts
• 10 Facts About Corals
• Ocean Sunfish Facts
• Sea Nettle Facts

A box jellyfish captures one fish in its tentacles even as it holds another in its stomach.

Secret Lives of Jellyfish: Robots, Genetics, and World Domination

Jellyfish have lived in the oceans longer than any other creature but now may be their time to shine.

Jellyfish are the oldest animals in the ocean—they’ve been swimming on our planet for more than half a billion years. But it is only recently that scientists have begun to understand these beautiful but deadly organisms, from the sophisticated way they propel themselves to the complex chemistry involved in their phosphorescent glow. The picture that emerges, according to Juli Berwald , author of the new book Spineless , is of an “incredibly well-adapted, super-elegant creature.”

Speaking from her home in Austin, Texas, Berwald, who has written for National Geographic, explains how the jellyfish’s glow revolutionized genetics; why robots are copying jellyfish; and how jellyfish are taking advantage of ocean acidification to expand their range and invade new waters.

The highlight of our summers on Long Island is when the moon jellies bloom and we get phosphorescent water at night—jellyfish can make the sea a magical place. Is that why you fell in love with them?

It wasn’t actually their beauty that initially got me into it. I was writing captions for a National Geographic story about acid seas by Elizabeth Kolbert. In that story there was a graphic showing the winners and losers in a future acidified ocean. Looking at the losers first, it was all things with shells, which dissolve in higher acidity. The winner side was things like algae, microalgae, kelp, and jellyfish. I thought, “Really? Do we know that for sure?”

My PhD is in ocean science, so I love to look into the scientific literature. I dug in and found there was this excitement and controversy in the literature about jellyfish and how their abundance was increasing in today’s damaged oceans. I thought, “ This is interesting.”

In terms of a muse to write about, they live on this line that is both angelic and demonic and nothing about them is clear-cut. They are absolutely gorgeous to look at and, you’re right, their bioluminescence is astonishing!

But their sting is vicious ! They may not just ruin your time at the beach. Some are actually deadly. The box jelly , the very toxic one that lives in the Pacific Ocean, can kill a man in three minutes and contains enough sting for 60 men. Unfortunately, because of climate change, its range is expanding down the coast of Australia into the Gold Coast, where there are popular surfing beaches.

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What can these apparently simple creatures tell us about evolution?

They’ve existed for well over half a billion years. They are certainly the oldest swimmer that still exists on our planet. There are roughly 200 species of the true jellyfish, but as we do DNA analysis we’re finding a lot of cryptic jellyfish. There’s probably another two thousand hydrozoan jellyfish , which is a cousin group.

Jellyfish can be as small as a few millimeters across, like the size of an eraser on a pencil, or as big as 500 pounds. And they’re not all clear. The larger ones, in particular, have developed pigments. A lot are red because, as you go down in the ocean, the red light disappears and they appear black, like a burglar wearing all black to avoid detection. Some are incredibly beautiful. One I saw in Japan has aquamarine disguise on top and maroon disguise on the bottom.

The fact that they’ve been around so long says that they’ve come up with a morphology, body structure, and adaptation to survive, hunt, and avoid being eaten, which is supremely elegant. In my opinion, it all comes down to the speed and force of their stinging cells, which are a masterful piece of biological evolution that explode with a force five million times the acceleration due to gravity.

The way jellyfish propel themselves through water is fascinating. Tell us about the extraordinary technology known as Robojelly.

When we think about walking on Earth, we think about pushing backward and creating a high pressure behind our foot. Jellyfish create a low-pressure system above their bell , which is stronger than the high-pressure system behind the animal, so it sucks itself through the water. When scientists started looking at other animals like lamprey eels, they found the same thing: a low-pressure system in front of the wiggle, which sucks the animal through the water.

Robojelly is a robotic jelly made out of silicon and these things called “actuators,” which are like fake muscles that contract. The initial idea was to see if you could create an undersea robot that moves through the water like a jellyfish. Now there’s a group building one that’s the size of a person and five feet wide. The idea is that it would sit deep in the ocean and report back, like a spy, and remain there for long periods of time, using very little energy.

Two moon jellies swim at the Shark Reef Aquarium in Las Vegas.

You write, “ GFP may be the most evolutionary successful gene of all time, it is even used as a biotechnical tool now.” What is it?

GFP is green florescent protein. Osamu Shimomura had been working with researchers at Princeton in the sixties to understand the jellyfish’s glow. He was able to purify the molecules that create the glow in the jellyfish, which are known as luciferin, luciferin being the enzyme. The glow was blue, but when jellyfish glow in the ocean, they’re green, so they found there was another molecule called GFP that takes the blue light and shifts it to green.

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That protein was then studied by two other scientists, Martin Chalfie and Roger Tsien. They discovered that, almost like you would attach a note to the beginning of an email, you could attach the genetic code for that GFP to the front of a gene to figure out what it was doing in an animal. The green glow would report when that gene was turned on by the animal.

GFP has revolutionized biotechnology. It’s been inserted into yeasts, rabbits, mice, brains, and was modified so that it reported not just green but lots of colors, like red, blue, and orange, so you could study the way many different genes were working in one organism. These three men received the 2008 Nobel Prize for Chemistry for their work.

Bioluminescence in jellyfish like this comb jelly provided scientists with a tool to understand genetics.

My wife loves jellyfish salad and you clearly do, too. What other cultures—and creatures—like to eat jellyfish ? And what does jellyfish actually taste like?

It’s been eaten in Asian countries for a thousand years. In order to eat it you have to remove the water fairly quickly because otherwise it will spoil, as bacteria live in water. In Asia, they remove it by soaking it for about a week in a combination of salt and alum. They then rehydrate it to rinse the alum and salt out.

You don’t have to cook it. You just slice it up and eat it as a salad. It has a crisp texture and not much flavor. But if you add soy sauce, vinegar, and some sugar, it tastes a lot like a crispy seaweed salad. It’s quite high in protein and extremely high in antioxidants.

Some people in Asia see it as medicinal, to treat rheumatoid arthritis because it’s all collagen. It’s also being investigated for its nutritional properties, especially in Italy. The problem is that alum is not so great for you. It’s got aluminum in it which has been associated with Alzheimer’s, so they’re looking for new ways to preserve it without soaking it in alum salt. A Danish woman has come up with a method using alcohol to suck the water out and has created these jellyfish chips.

When I started working on the book, people didn’t realize how many different creatures eat jellyfish because the main way we look at what-eats-what in the ocean is by looking at gut contents, i.e. catching a fish, slicing its gut, and looking at what you see. You’re never going to see jellyfish!

But using DNA technology, we’re finding more and more creatures eat jellyfish. Leatherback turtles and the biggest bony fish in the sea, the Mola mola , live almost entirely on jellyfish. Recently we’ve discovered that penguins and albatrosses eat a lot of, and love, jellyfish. So jellyfish is on the menu for a lot of creatures in the ocean.

Sea walnut jellyfish rest in the water at the Gulf Specimen Marine Lab and Aquarium in Florida.

The Suez Canal has become a route for invasive species moving between the Mediterranean and the Red Sea. Marine protected areas are also vulnerable. Talk us through the issues here.

The shipping industry is moving jellyfish around the planet. When ships take on ballast water, they can take on jellyfish as well, and then dump them out in a new place that may be hospitable to jellies. So, you can get big invasions like what happened in the Black Sea with the comb jelly, which took down the entire ecosystem there.

The rhopoema nomadica , or nomadic jellyfish, is native to the Indian Ocean but in the eighties, they started turning up in the eastern Mediterranean, presumably through the Suez Canal. Now this jellyfish forms massive plumes, kilometers wide, along the coast of the eastern Mediterranean and Israel. For the first time, recently, a huge plume formed off Egypt’s coast, and off Turkey and Lebanon. It’s a bad stinger. When it blooms intensely, it can get sucked into the watering systems that power plants use to cool machinery. Jellyfish are gooey, like a sink stopper, and clog the intake systems, so they have to shut down power plants until they can clear the bloom away.

Marine protected areas, which are like national parks on land, are seen as an important way for us to protect the richness, biodiversity, and health of the ocean. Because there are no fences, fish will find sanctuary and there will be a spillover effect outside the sanctuary where fishing is allowed, causing catches to actually increase. But invasive species can also go into the marine protected areas and take advantage of what’s there, as happened in Italy recently. This is not to say we should not have marine protected areas! It’s more complicated.

Some scientists say we are in the planet’s sixth major extinction and, if we aren’t careful, jellyfish are in place to take over whole ecosystems. Are we about to enter the age of the jellyfish?

This is such a hard question because it can tend toward fear mongering and sensationalizing. I also feel uncomfortable with that because we can’t predict where and when jellyfish blooms will occur. Jellyfish have been systematically neglected by science and the media for most of the 20th century because our understanding of the ocean is biased towards what is pulled up in nets: hard, rigid things. But jellyfish science is now reaching this explosive period of understanding.

Can they survive acidification? There are places around the world where we see sustained blooms of large jellyfish, like the eastern Mediterranean, the coast of Japan or Namibia, where ecosystems have become dominated by jellyfish. But, globally, I’m not willing to say that we know what’s going on. The ocean needs a lot more of our attention, and a lot more study. Jellyfish are very complicated. We don’t understand them. That’s part of what makes them so fascinating.

This interview was edited for length and clarity.

Simon Worrall curates Book Talk . Follow him on Twitter or at simonworrallauthor.com .

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The jellyfish, an animal that stings!

Jellyfish belong to the Cnidaria phylum, which comes from the Greek word Cnidae , literally meaning “stinging”, and includes sea anemones, cerianthus and reef-building corals, as well as gorgonians, alcyons and jewel coral.

Are jellyfish immortal?

Organized like an umbrella, the body of a jellyfish is composed of an umbrella, which lets hang, in its center, the manubrium ended by the mouth. The umbrella is bordered by filaments, called tentacles.

There is a great diversity of jellyfish, nearly a thousand species ranging from a few millimetres (75% of jellyfish are invisible to the naked eye) to two metres in diameter.

The shapes are also very varied: round, square, flat, domed, massive or aerial… Their periphery can be smooth or lobed, their tentacles absent (as in rhizostomes) or very numerous (up to 800 in Cyanea ).

Why Do jellyfish sting?

The main characteristic of Cnidaria is their stinging cells, called cnidocytes, present on the tentacles but also sometimes on the whole jellyfish.

Jellyfish are best known to the general public for the annoyance they cause bathers. If the species present on our coasts are at the origin of many inconveniences, other species, like the tropical cubomedus can be infinitely more dangerous, even deadly.

The cnidocyte contains a vacuole, a pocket filled with venom in which a mini-harpoon (a hollow spiral filament studded with spines) is immersed, controlled by a tiny hair, the cnidocil. When the cnidocil touches a prey, the mini-harpoon is expelled, inoculating its venom.

The cnidocytes are lost as they remain attached to the prey, but new cells are regenerated within 24 hours. These cells make their own toxin and filament.

What to do in case of jellyfish stings?

A ROBUST LIFE CYCLE ... TO IMMORTALITY

Despite their apparent fragility, jellyfish are remarkably robust, close to immortality. Their originality – and certainly their greatest asset – is to have an adaptive life cycle. Their mode of reproduction (sexual and asexual) is adapted to environmental conditions.

The gelling of the oceans

Most specialists now agree that the ocean is becoming gelatinous: gelatinous organisms, primarily jellyfish, are proliferating in a sometimes spectacular way, breaking with the old cycles of appearance and disappearance linked to climatic conditions.

However, the impact of jellyfish is far from being limited to the leisure sector, and many maritime activities are now penalized by their armadas criss-crossing the seas: beach closures, ruined fisheries, massive loss of fish in aquaculture farms, shutdown of nuclear power plants.

Spectacular assaults that often make the headlines.

Theme sheet

From the origin of the senses to the nobel prize.

Despite their apparent simplicity, jellyfish have much to teach us. While the group of cnidarians separated from other animals more than 600 million years ago, jellyfish possess sensory sensors, light or balance, strangely similar to ours.

In order to orient themselves in open water, without landmarks, some species of jellyfish have tiny organs, the statocysts, which are true models of the organ of balance, located in the inner ear in humans.

In the most advanced jellyfish, the statocysts are grouped with an olfactory fossa and visual cells in an organ called rhopalia. We can consider that certain jellyfish have a premise of what will become the brain in other species.

MEdUSES IN HISTORY OF SCIENCE

It’s no coincidence that jellyfish are called that. Carl Linnaeus, the Swedish naturalist who, in the 18 th century, catalogued, named and classified in a systematic way most of the living species known at his time, recognized in these spherical animals surrounded by tentacles, the famous jellyfish of the Greek myth with the hair of snake which petrifies by its simple glance.

Find the history of the knowledge of jellyfish from Aristotle to our days, through the French Revolution which influenced the young naturalist François Péron for the choice of species names .

The Oceanographic Institute's Fact Sheets on Jellyfish

Thematic sheets of popularization realized for you by the best experts…

Jellyfish in video

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What are jellyfish made of?

Only about five percent of the body of a jellyfish is solid matter; the rest is water ..

Fascinating, elegant, and mysterious to watch in the water, take a jellyfish out of the water, and it becomes a much less fascinating blob. This is because jellyfish are about 95 percent water.

Lacking brains, blood, or even hearts, jellyfish are pretty simple critters. They are composed of three layers: an outer layer, called the epidermis; a middle layer made of a thick, elastic, jelly-like substance called mesoglea; and an inner layer, called the gastrodermis. An elementary nervous system, or nerve net, allows jellyfish to smell, detect light, and respond to other stimuli. The simple digestive cavity of a jellyfish acts as both its stomach and intestine, with one opening for both the mouth and the anus.

These simple invertebrates are members of the phylum Cnidaria, which includes creatures such as sea anemones, sea whips, and corals. Like all members of the phylum, the body parts of a jellyfish radiate from a central axis. This “radial symmetry” allows jellyfish to detect and respond to food or danger from any direction.

Jellyfish have the ability to sting with their tentacles. While the severity of stings varies, in humans, most jellyfish stings result only in minor discomfort.

More Information

• Immortal Jellyfish (video)
• Jellyfish Gone Wild (National Science Foundation)

Last updated: 01/18/24 Author: NOAA How to cite this article

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Fact vs. fiction: 3 things you thought you knew about jellyfish

Jellyfish. Jellies. Sea nettles. Whatever you call them, the likelihood of running into these stinging tentacled creatures generally increases in the summer.

This medusa belongs to the genus Cyanea, a jellyfish well-known to bloom and occur in large numbers in surface waters. (Image credit: NOAA)

Jellyfish have a complicated relationship with humans: They are often feared by beachgoers because of their sting. They can get unintentionally caught up in commercial fishing nets. Some jellies can even clog intake pipes of coastal power and desalination plants, and in high concentrations, can force closures of popular beaches.

For scientists, however, jellyfish are fascinating research subjects – they play important roles in the marine ecosystem and are a key source of food for some fish and sea turtles. Some even protect commercially valuable species, such as oysters, from predators. Whatever your view may be, many misconceptions exist about jellyfish. Let’s bust the Top 3 myths:  

MYTH #1: Jellyfish are all the same species On the contrary, there are more than 200 documented species of true jellyfish (and many more of their stinging relatives) across the globe. The environmental conditions required for each species to thrive can differ. In fact, NOAA and Smithsonian Institution scientists recently found that sea nettles in the Chesapeake Bay are considerably different than those in the open ocean and recognized it as a new species.

The jelly (hydromedusa) is in a family of hydromedusae called Rhopalonematidae, which is known for the canals running vertically on the inside of the bell, gonads attached to these canals, and sometimes having two sets of tentacles. In this video, you can see the perfectly relaxed arrangement of the two sets of tentacles; scientists think this is a position that allows for optimum feeding in the midwater environment at 3,000 meters. Through remotely operated vehicle video observations such as this, we can learn much about the animals in the midwater and what they are up to when we can catch them in an undisturbed manner.

MYTH #2: Jellyfish "go after" people Not true. Any contact with jellyfish is incidental. Humans are not on their menu, but when we are in their environment we can get in the way of their tentacles. While jellyfish don't have a brain, they can sense light and have coordinated swimming behaviors, which help keep them in good places to hunt for microscopic plants and fish eggs/larvae, or other prey like fish, worms, and crustaceans.

This stunningly beautiful jellyfish was seen during Dive 4 of the 2016 Deepwater Exploration of the Marianas expedition on April 24, 2016, while exploring the informally named "Enigma Seamount" at a depth of ~3,700 meters. Scientists identified this hydromedusa as belonging to the genus Crossota. Note the two sets of tentacles — short and long. At the beginning of the video, you'll see that the long tentacles are even and extended outward and the bell is motionless. This suggests an ambush predation mode. Within the bell, the radial canals in red are connecting points for what looks like the gonads in bright yellow.

MYTH #3: Applying urine to a jellyfish sting can reduce the pain Perhaps the most interesting of myths, the use of urine to treat stings has been tested and proven unhelpful. A better idea? Try an acidic liquid like vinegar. There are also several commercially available products marketed for stings.

What to do if you get stung: First, look for any tentacle adhering to skin, and flush the area well with cold ocean water. Do not rub the sting area because you could inadvertently distribute the venom further into the body. Then vinegar or evidence-based commercial product should be applied if there is continuing pain.

A new tool undergoing testing NOAA scientists are working on a way to forecast jellyfish , using the Chesapeake Bay as a testing ground, so residents and business owners can understand the probabilities of encountering jellies based on changing environmental conditions – such as salt concentration and temperature of bay water. More >  Get your fill of facts about jellyfish biology and their life history offsite link – including some more stunning  close-up photos .

Related Features //

Tips on How to Write a Biology Essay: Learn from the Example of Jellyfish Essay

How to Write a Biology Essay

In this article, we will guide you on how to write a perfect biology essay from scratch. You’ll find various tips to help you excel in writing your essay and creating a paper worth the highest grades. We also prepared a jellyfish essay example for you, so it can be easier to enhance all the specifics and structure of this kind of paper.

What is Biology Essay

A biology essay is a student-written work where you present arguments and ideas about a particular biological topic. The essay on biology can take different forms like argumentative, cause-and-effect, descriptive, detailed analysis, or ‘how-to’ instruction, depending on the professor’s guidelines and writer’s preferences. 

A descriptive paper can explain a biological subject, while an argumentative one provides evidence to support a point of view. It’s up to you to choose which type is more suitable for the topic you’re writing about. The most common type is a cause-and-effect essay explaining an event’s reasons and consequences. 

How to Craft a Perfect Essay About Biology

Writing is an art form that requires time and effort. But if you prefer someone else to write the paper for you, you can just text the experts, ‘ do my homework for me ,’ and consider it done. 

Here is the step by step instruction to organize the process for desired results. 

Choose Your Biology Essay Topic

To get a good grade:

• make your paper informative and enjoyable by choosing a topic you wish to explore. 
• Use a brainstorming technique to generate 30-50 options for biology essay topics and research to create a shortlist. 
• Keep a notebook to jot down your ideas.

Choose a Question for Research

When writing a biology essay, use a scientific approach by selecting a research question related to your topic. Always avoid overly complex or apparent questions. You can also text our profs ‘ write my research paper ,’ and it can be done in a blink.

Create an Outline

Always have a clear plan when writing biology essays while starting a paper. Use a 5-paragraph structure with an outline to keep your main idea and arguments organized. Use any format that works best for you and adjust as needed. Discard any ideas that don’t fit your research question.

Use a Strong Thesis Statement

The introduction should end with a strong thesis statement synthesizing the overall essay, conveying the research question and your point of view. The paper is ineffective without a clear thesis, as readers may not understand your position.

Use Citation and References

Include a list of references in your academic papers, such as biology essays, to avoid plagiarism and provide data sources. Use the appropriate citation style, like APA or CSE, and consult a guide for requirements.

How to Structure a Biology Essay

Ensure your essay has an attention-grabbing introduction, a detailed body, and a solid conclusion with distinct sections. Use around seven paragraphs for the main body, adjusting as needed for the required word count.

Biology Essay Introduction

In the introduction of your essay about biology, showcase your expertise by providing a brief background of the topic and stating the essay’s objective. For a research paper, explain why the study is relevant. Make sure the reader understands the essence of your subject.

The body section of your essay on biology should focus on supporting and defending your thesis statement. To achieve this, make a list of essential points to cover and address each one step by step. Starting a new paragraph for each point ensures neatness and a continuous flow. 

In conclusion, restate your thesis statement and summarize supporting points to solidify your arguments. Avoid introducing new concepts, and leave a lasting impression on your instructor.

Jellyfish Essay - Example of a Biology Essay About a Fascinating Creature of the Ocean

Jellyfish, also known as jellies, are incredible creatures of the ocean. They’re members of the phylum Cnidaria, including corals and sea anemones. You can find jellyfish in every ocean around the globe, from the surface to the depths of the sea. 

Do you know what shape the jellyfish body has?! It’s one of their most unique features. Their bell-shaped body comprises a soft, jelly-like substance called mesoglea, found between two cellular layers. The outer layer of cells, the epidermis, is thin and flexible, while the inner layer, the gastrodermis, contains the jellyfish’s digestive system. At the bottom of the bell is the mouth, surrounded by tentacles armed with stinging cells called nematocysts. 

The jellyfish tentacles consist of venom-filled sacs, which can be potentially dangerous and life-threatening. Considering the severity of its sting, researchers have gathered information on how to treat it effectively. Use thick clothing, tweezers, sticks, or gloves to alleviate the sting. It’s crucial to avoid touching the sting with bare skin since the venom can cause severe harm. Always dispose of the tool used for removing the sting to prevent re-stinging. 

Jellyfish are creatures that feed on small fish and other tiny marine organisms. They capture their prey using the tentacles and bring it to their mouth. Once the food is inside the jellyfish, it’s broken down by digestive enzymes and absorbed into the gastrovascular cavity. 

An exciting thing about jelly is its life cycle. They go through several stages of development, starting as a tiny, free-swimming larva and then growing into a polyp. The polyp stage is stationary, and the jellyfish attaches itself to a surface using a sticky pad. During this stage, the jellyfish reproduces asexually, creating clones of itself. These clones then break off from the polyp and develop into the familiar bell-shaped body of the adult jellyfish. 

Jellyfish play an essential role in the ocean’s ecosystem too. They’re a food source for many marine creatures, including sea turtles and some fish species. They also help to control the population of tiny marine animals by feeding on them, and their waste products contribute to the nutrient cycle in the ocean.

However, jellyfish populations can sometimes explode and become a nuisance. This phenomenon mostly occurs when their natural predators are eliminated from the ecosystem or when water conditions, like temperature and salinity, are conducive for jellyfish growth. In cases where jellyfish populations reach excessive levels, they can clog fishing nets and interfere with other human activities in the ocean.

Jellyfish really are stunning creatures of the ocean. They’re diverse, with many different species, and are essential to the marine ecosystem. While they can sometimes become a nuisance, they’re vital to the ocean’s food web and nutrient cycle. Studying jellyfish can give us a greater understanding of the complex and interconnected systems that make up our oceans.

Practical Tips for Creating Perfect Academic Papers

Developing writing skills is crucial for your academic success regardless of your major. Check out these tips we provided for improving your writing. But if you aren't fond of writing, you can easily hand it to professionals by saying, ‘ do homework for me .’

Search for Samples or Examples

To improve your writing, analyze examples of well-written biology essays or research papers. Although not all online samples are perfect, they can still provide insights into what works and what doesn’t. However, avoid plagiarism and ensure your paper is original by presenting fresh ideas and a unique perspective. 

Read Whenever You Can

Develop your writing skills by reading widely and extensively. Look for biology papers in scientific journals, websites, or books. Don’t forget to take notes on interesting points that you can use in your papers later.

Practice Makes Perfect

Don’t expect to write a perfect paper on your first try, so take every opportunity to practice your writing. Find a mentor if needed and use online resources to learn from your mistakes and improve your skills.

Always Organize Your Writing Process

Organize your work process instead of waiting for inspiration by defining stages, scheduling time for each task, and eliminating distractions. Don’t wait for mood to write an essay about biology; use different strategies to overcome writer’s block.

Proofread and Get Other Feedback

It’s hard to assess your own work accurately. Seek feedback from peers or instructors to identify strengths and weaknesses to improve upon. Don’t wait for your professor’s feedback to know if your biology essay is good. 

Interesting Biology Essay Topics from Our Experts to Practice Your Writing

In this paragraph, we listed different biology essay topics from which you can choose your preferred one and practice writing to excel in your academic papers.

• A jellyfish - my favorite creature
• Facts about animal behavior
• Biodiversity conservation
• Chemical Ecology
• Impacts of air pollution
• Acid Rain’s impact on wildlife
• The greenhouse effect
• Causes of global warming
• Effects of climate change on nature
• Ways to avoid water pollution

These are interesting topics and also some of the most significant environmental problems. Choose the one you like and practice.

Final Thoughts

This article provides tips that will definitely make your writing process easier and more effective. Adjust these tips while writing your biology paper and structure it as we did in the jellyfish essay example. But if you still prefer a professional to do it for you, contact us by writing ‘ do my research paper ,’ and our experts will handle it.

• Plagiarism Report
• Unlimited Revisions
• 24/7 Support