Tag Archives: jellyfish

Ever got a ‘phantom sting’ while swimming? This might explain it

If you ever went swimming in warm waters, you may have experienced a curious phenomenon: the calm and crystalline waters suddenly became a stinging substance uncomfortable to the touch. But when you look around, there’s nothing there.

Or so it seems to you.

Credit Wikipedia Commons

Researchers were aware of this reported phenomenon and believed it to be part of a defensive strategy of anemones, sea lice or inverted jellyfish — all of them typical species of warm water. The latter of them recently caught the attention of a group of researchers in the US, whose results were published in Nature Communications Biology. According to their study, even the water surrounding upside-down jellyfish often stings to the touch.

The scientists thought that the mucus generated by inverted jellyfish, also known as Cassiopea xamachana, could be responsible for this curious itching. This type of jellyfish is commonly found in Florida, Hawaii and the Caribbean, usually stuck to the ocean floor. They took samples of the mucus and observed it under the microscope, noting that it contains a series of curious balls, spinning and moving to the sound of the gelatinous substance that envelops them.

A closer look showed that these spheres were composed of different cells, most of them very sharp.

“This discovery was both a surprise and a long-awaited resolution to the mystery of stinging water,” said Cheryl Ames, associate professor at Tohoku University. “We can now let swimmers know that stinging water is caused by upside-down jellyfish, despite their general reputation as a mild stinger.”

The team also observed a series of unusual cylindrical filaments, which are believed to help these balls travel more efficiently through the water.

They even noticed the presence of a specific type of algae, which normally live within jellyfish, establishing with them a symbiotic relationship, in which jellyfish provide protection and algae generate nutrients.

When studying some specimens of the jellyfish, the researchers realized that the balls found in the mucous were concentrated in the tentacles of the animal. They saw that the jellyfish tended to release the balls and pass them into the water through the mucus. This way they were defending against their enemies and capturing prey from which to feed. These structures, called cassiosomes, can kill prey and are the likely cause of ‘stinging water’ — the phantom stinging reported by many snorkelers and fishermen in tropical waters.

Life cycle stages of C. xamachana and its cassiosome-laden mucus. Imager credits; Ames et al. / Communications Biology, 2020).

They reached this conclusion by checking that in contact with the spheres some small crustaceans, such as brine shrimp, died or were weak enough to be easily ingested by the jellyfish. All this is due to the presence of three toxins, which could be characterized by the researchers. It is true that symbiotic algae provide the jellyfish with some of the energy necessary for its survival, but this is not always enough.

“Venoms in jellyfish are poorly understood in general, and this research takes our knowledge one step closer to exploring how jellyfish use their venom in interesting and novel ways,” Anna Klompen, a graduate student at the University of Kansas who was part of the study, said.

Know that we know the reason for the stinging sensation, the next challenge for researchers will be to know how to avoid that from happening. The team is now looking at whether the jellies release the venom more at certain times of the day or in response to certain types of disturbances.

This discovery could also make an impact in biotechnology, researchers conclude.

The study has been published in Communications Biology.

Scientists strap controller onto jellyfish, turn it into a super-fast cyborg-jellyfish

Jellyfish never stop. Twenty-four hours a day, seven days a week, they move through the water in search of food such as shrimp and fish larvae. They are more efficient than any other swimmer in the animal kingdom, using less energy for their size than graceful dolphins or cruising sharks. They’re not very fast, though. That had to change, some Stanford researchers thought, who literally strapped a motor on the invertebrates, turning them into fast-moving marine cyborgs.

A moon jelly with a controller attached. It swam about three times faster when the device was turned on. Credit: Science Advances.

On average, the jellyfish’s cost of transport — measured by the oxygen they use to move — is 48 percent lower than any other swimming animal. The recent biohybrid made at Stanford, however, blows everything that came before it out of the water. According to the study published in Science Advances, the swimming cyborg is 10 to 1,000 times more energy efficient than other swimming robots.

Researchers sourced moon jellyfish (Aurelia aurita) from the Cabrillo Marine Aquarium in San Pedro, California, and embedded a waterproof propulsion system into their muscle tissue. The system consists of a lithium polymer battery, a microcontroller, a microprocessor, and a set of electrodes. The controller generates an electrical signal that travels through the electrodes into the jelly muscles, causing them to contract.

The components of the controller that turned jellies into cyborgs. Credit: Science Advances.

During experiments, the research team split their jellies into three groups: one swam on their own with no electronic augmentation, acting as the study’s control, one had a controller attached to the jellies that was turned off to see whether the device affected the animals’ motion in any way, and a third had the controller switched on.

Adding the controller with no electrical stimulation seems to have made little effect on the jellyfish. Those that had the controller activated increased their swimming speed nearly three times, from 0.15 to around 0.45 body diameters per second.

“Swimming speed can be enhanced nearly threefold, with only a twofold increase in metabolic expenditure of the animal and 10 mW of external power input to the microelectronics. Thus, this biohybrid robot uses 10 to 1000 times less external power per mass than other aquatic robots reported in literature. This capability can expand the performance envelope of biohybrid robots relative to natural animals for applications such as ocean monitoring,” the Stanford researchers wrote.

In the future, the researchers want to experiment further in order to increase both speed and energy efficiency.

As for the jellyfish’s health, the researchers wrote in their study that moon jellies are invertebrates with no central nervous system so they feel no pain. They note that they had taken precautions to avoid any unnecessary tissue damage to the animals. After the experiments were over, the controllers were removed and the jellies healed on their own.

Box jellyfish. Credit: Wikimedia Commmons.

Scientists find potential antidote to world’s most venomous sea creature

Box jellyfish. Credit: Wikimedia Commmons.

Box jellyfish. Credit: Wikimedia Commons.

The Australian box jellyfish (Chironex fleckeri) can carry enough venom to kill 60 people — that’s more venom than any other animal on Earth. When it doesn’t kill, the jellyfish’s sting is known to cause excruciating pain. The worst part about this jellyfish’s sting is that there is no way to neutralize it once it happens — but this may soon change. Using gene editing technology, Australian researchers at the University of Sydney identified the mechanism by which the sea creature’s venom destroys human cells and found drugs that seem to at least partially block this ability.

In order to find out how the box jellyfish venom acts upon the human body, the researchers painstakingly used CRISPR gene editing to knock out a different human gene from millions of individual human cells. One by one, the researchers went through each cell looking for those that survived the venom.

“It’s the first molecular dissection of how this type of venom works, and possibly how any venom works,” the study’s lead author Raymond Lau said in a statement.

The findings suggest that the venom targets the human skin where it interacts with cholesterol. When the researchers administered a drug (cyclodextrins) that eliminates cholesterol and is already approved on the market, they found that it can also work as an antidote as long as it was administered 15 minutes after a sting. The drug was tested on human cells in a lab dish and on live mice. By blocking the venom’s ability to interact with cholesterol, some of the pain should also be blocked.

“By putting the evidence together, we worked out which genes the box jellyfish venom needs to target in order to kill human cells in the lab. One we identified is a calcium transporter molecule called ATP2B1, and is present on the surface of cells,” Greg Neely, one of the authors of the new study, wrote for The Conversation.

The researchers say that they don’t know yet if the drug they identified can stop a heart attack — this is a question which they hope to answer in an upcoming new study.

What’s particularly interesting, however, is that the same method can be used to study other types of venom for which there currently isn’t an antidote. This was only the first time that CRISPR was used to find an antivenom and it certainly won’t be the last.

The rotary actuated dodeahedron (RAD) sampler has five origami-inspired “petals", which fold up to capture a soft-bodied marine organism, such as a jellyfish. Credit: Wyss Institute at Harvard University.

Scientists design ‘Pokéball’ that safely captures even the most delicate underwater creatures

The rotary actuated dodeahedron (RAD) sampler has five origami-inspired “petals", which fold up to capture a soft-bodied marine organism, such as a jellyfish. Credit: Wyss Institute at Harvard University.

The rotary actuated dodeahedron (RAD) sampler has five origami-inspired “petals”, which fold up to capture a soft-bodied marine organism, such as a jellyfish. Credit: Wyss Institute at Harvard University.

You better look out, Squirtle! Researchers at Harvard University and the Radcliffe Institute for Advanced Study recently demonstrated an origami-inspired polyhedral enclosure that can capture and release delicate sea creatures, such as jellyfish or squidsf, without causing any harm.

Gotta catch em all! 

In order to study marine creatures, researchers often have to rely on bulky underwater equipment that isn’t suited for the capture of soft-bodied creatures, which all too frequently get hurt or even killed.

“We approach these animals as if they are works of art: would we cut pieces out of the Mona Lisa to study it? No – we’d use the most innovative tools available. These deep-sea organisms, some being thousands of years old, deserve to be treated with a similar gentleness when we’re interacting with them,” said collaborating author David Gruber, who is a Radcliffe Fellow and Professor of Biology and Environmental Science at Baruch College, CUNY.

The idea for a pokéball-like robotic device was seeded by first author Zhi Ern Teoh, who during his stint at the Harvard Graduate School of Design was studying folding mechanisms through computational means. Brennan Phillips, who used to work in the same lab at Harvard’s Wyss Institute, saw some of Teoh’s designs that involved folding a flat surface into a 3D shape using motors, and suggested that these could be adapted to capturing sea creatures.

Teoh got to work and designed five identical 3D-printed polymer petals, which are attached to a series of rotating joints that form a scaffold when linked together. A single motor is used to apply torque to the point where the five petals meet, causing the entire structure to fold up into a hollow dodecahedron — a twelve-sided, almost-round box.

The folding is entirely directed by the origami-inspired design of the joints and the shape of the petals, requiring no additional energy input.

First author Zhi Ern Teoh tests the RAD sampler, mounted on the ROV Ventana. Credit: Wyss Institute at Harvard University.

First author Zhi Ern Teoh tests the RAD sampler, mounted on the ROV Ventana. Credit: Wyss Institute at Harvard University.

In order to test their device, called the Rotary Actuated Dodecahedron (RAD), the researchers traveled to Mystic Aquarium in Mystic, CT. There, the team proved that RAD was able to collect and release moon jellyfish underwater. The next step was testing RAD in-field; the device was mounted on an underwater remotely-operated vehicle (ROV), which dived to depths of 500-700 m (1,600-2,300 ft.). Using a joystick, a human controlled ROV’s manipulator arm to operate the sampler and capture squid and jellyfish in their natural habitats. During both capture and release, no creature was harmed.

“The RAD sampler design is perfect for the difficult environment of the deep ocean because its controls are very simple, so there are fewer elements that can break. It’s also modular, so if something does break, we can simply replace that part and send the sampler back down into the water,” said Teoh in a statement. “This folding design is also well-suited to be used in space, which is similar to the deep ocean in that it’s a low-gravity, inhospitable environment that makes operating any device challenging.”

Teoh and colleagues now plan to design a more rugged version that is more suited to heavy-duty applications, such as marine geology.

The researchers, however, envision a far wilder version of RAD, one equipped with all sorts of sensors, but also a DNA sequencer, such that data can be collected about the size, properties, and genome of a captured soft-bodied animal — before the animal is safely released. It’s “almost like an underwater alien abduction,” commented Gruber.

The findings were reported in the journal Science Robotics. 

In the future, we could be all snacking on jellyfish chips

Would you eat a jellyfish? Don’t be so quick to say no, researchers say. You might be surprised.

Fancy a chip? Credits: Mie Pedersen.

We rarely give it much thought, but texture plays an important role when it comes to food. As any good chef who’s worth his salt knows, changing the texture can make a dramatic difference in how we perceive taste. So if I’d tell you to imagine tasting a jellyfish, you’d probably imagine a slimy, gummy sensation. But when Mathias P. Clausen, a postdoctoral fellow at the University of Southern Denmark in Odense, Denmark, had a taste of a jellyfish snack, he was surprised by its crunch.

“Tasting jellyfish myself, I wanted to understand the transformation from a soft gel to this crunchy thing you eat,” Clausen said.

Eating jellyfish might seem disgusting, but they’ve long been a staple in some parts of Asia. Traditionally, jellyfish were marinated in salt and potassium alum for several weeks, resulting in a rather crunchy, pickle-like texture. But this process is time-consuming and infuses the snack with a very specific, some say even unpleasant, taste.

Clausen and his colleagues applied their knowledge of biophysics and biochemistry to develop crispy jellyfish chips in a matter of days, potentially opening the world up to a new type of food.

“Using ethanol, we have created jellyfish chips that have a crispy texture and could be of potential gastronomic interest,” Clausen said.

The process is problematic because the molecular make-up of the jellyfish has rarely been properly studied. The team found that long fibrous filaments in the gelatinous jellyfish bell transform during the cooking process, creating the crunchy feel.

“Little is known about the molecular anatomy of the jellyfish,” Clausen said. “We are still not completely sure which structures we are visualizing.”

The reason why eating jellyfish is so interesting is because populations — often, invasive populations — are booming. As humanity greatly overfishes the oceans, jellyfish have risen to fill in that void. They also have numerous health benefits, being rich in vitamin B12, magnesium, phosphorus, iron, and selenium.

According to Clausen, jellyfish may be a very viable and healthy food source — one that’s almost completely unexploited at this moment. His work could lead to an efficient way of obtaining and preparing said food, but researchers first need to understand exactly what’s happening at a chemical level when you cook a jellyfish.

“As this is pioneering work, I think using tools available to us to tackle the science of good eating can open peoples’ eyes for a completely new scientific field,” Clausen said.

The study hasn’t been peer-reviewed yet but will be presented at 62nd Biophysical Society Annual Meeting, held Feb. 17-21, in San Francisco, California.

This image shows two different jellyfish. At left is US Atlantic sea nettle (Chrysaora quinquecirrha) and at right is the Atlantic bay nettle (Chrysaora chesapeakei). Credit: Shannon Howard, South Carolina Aquarium; Keith Bayha.

Common jellyfish is actually two distinct species

Biologists at the University of Delaware discovered that a widespread and well-known jellyfish found along the U.S. East Coast is actually two distinct species.

This image shows two different jellyfish. At left is US Atlantic sea nettle (Chrysaora quinquecirrha) and at right is the Atlantic bay nettle (Chrysaora chesapeakei). Credit: Shannon Howard, South Carolina Aquarium; Keith Bayha.

This image shows two different jellyfish. At left is US Atlantic sea nettle (Chrysaora quinquecirrha) and at right is the Atlantic bay nettle (Chrysaora chesapeakei). Credit: Shannon Howard, South Carolina Aquarium; Keith Bayha.

Ever since it was first formally described 175 years ago, the common sea nettle jellyfish — which can be found in abundance in the Chesapeake Bay and Rehoboth Bay — has always been assumed to a be a single species. In took someone with a keen eye and a lot of patience like Keith Bayha, a University of Delaware alumnus and now a scientist for the Smithsonian’s National Museum of Natural History, for us to realize that this jellyfish is, in fact, two distinct species: an ocean-based species (which retains the name Chrysaora quinquecirrha, “sea nettle”) and a bay-based species (Chrysaora chesapeakei, “bay nettle”).

This insight was made possible thanks to the latest DNA sequencing techniques.

“Before DNA came along, people in museums looked at organisms and counted spines and bristles, measured things, and sorted organisms by their physical characteristics in order to identify species,” said University of Delaware professor Patrick Gaffney in a statement. “In the case of this jellyfish, which has been commonly known for centuries, Keith found through DNA sequencing that there were actually two groups.”

After genetic sequencing revealed significant differences in some of the sea nettle jellyfish, the scientists took a closer look at the physical characteristics of various individuals. As it turns out, the ocean-based sea nettle jellyfish is larger and has approximately 40 percent more tentacles (40, as compared to 24) than its bayside counterpart. What’s more, the ocean sea nettle has a larger bell and shorter tentacles than the bay nettle species.

“When you go back and pay close attention, you start counting the number of stinging cells and types, you see discrete differences that correspond to the DNA,” said Gaffney. “In many cases, when we plotted the data, the graphs looked entirely different with no overlap, reaffirming that it was two species.”

The findings published in the journal Peer J could have important implications, some of them commercial. For instance, bay nettle jellyfish prey on comb jellies called Mnemiopsis, which are predators of Eastern oyster larvae. The Eastern oyster, widely found on the Atlantic and Gulf Coasts, is the most consumed type of oyster. The industry could, for instance, propose measures that introduce more bay nettles to enhance Eastern oyster production. Another interesting find is that the bay nettle prefers less salty waters like estuaries. NOAA compiles a daily jellyfish forecast for the Chesapeake Bay, where jellyfish blooms can be a nuisance. The differences in the two species might explain why scientists found it particularly difficult to predict jellyfish bloom in the area very accurately.

“It’s not that I did anything that different, it’s just that no one else looked for a very long time,” Bayha said. “Jellyfish are something people don’t pay attention to because they’re fleeting. They come and go, are difficulty to study, and they don’t have hard parts like shells that wash up on shore.”

Cassiopea jellyfish are the only animals we know of that sleep despite lacking a centralized nervous system. Credit: Caltech

You don’t need a brain to sleep, and we have snoozing jellyfish to prove it

It turns out even brainless creatures such as jellyfish need to sleep. This extraordinary discovery, reported on by researchers at the California Institute of Technology, Pasadena, makes sleep even more mysterious than it already is.

Cassiopea jellyfish are the only animals we know of that sleep despite lacking a centralized nervous system. Credit: Caltech

Cassiopea jellyfish are the only animals we know of that sleep despite lacking a centralized nervous system. Credit: Caltech

When you’re tired as heck and finally hit the sack, there aren’t many things that can disturb your slumber. That’s the case for me, at least, much to the despair of my fellow ZME staff writers who have to snooze my alarm clocks while I continue to drool on the couch. When we do, however, have to forgo sleep, that little thinking box up your shoulders goes out of order — until you eventually tap shut down. 

This oh so familiar pattern has the obvious implication that sleep and higher nervous functions are deeply connected, with the former replenishing cognition. It follows that you need a sort of brain to sleep in the first place. Or so we used to think.

The brainless sleeper

Paul Sternberg, a biologist at Caltech, along with colleagues, wanted to see just how little brain an animal has to have to need sleep. They lowered the bar to no brain at all by studying several jellyfish species from the genus Cassiopea. These particular jellyfish hang motionless in shallow waters with their tentacles facing upward towards the water’s surface. To feed and sweep away waste, the animals pulse their bells about once per second.

Inside aquariums, the biologists studied 23 jellyfish with special motion-sensing cameras that snooped day and night for almost a week. During the night, the animals clearly slowed their movement to only 39 pulses per minutes compared to the typical 60 per minute at day.

Where these slow-pulsers asleep? The Caltech grad students lifted some of the jellyfish from their resting place at the bottom of the aquarium towards the surface and measured how quickly they reacted. During the night, jellyfish were far slower to respond by moving back to the bottom of the tank, just like a person is groggy and sluggish after being abruptly woken up.

At night, Cassiopea jellies pulse less frequently. This may be a clue that the animals are sleeping. Credit: Caltech.

At night, Cassiopea jellies pulse less frequently. This may be a clue that the animals are sleeping. Credit: Caltech.

The team even went a step further by sending pulsing water across the tank at night every 20 minutes for 6 or 12 hours. They found the jellyfish were not nearly as active the next morning as their peers who were left to their own devices. When the bothered jellyfish were finally left off the hook the following night, they seemed to have recovered by the next day. Again, this is parallel to how animals with brains would react if sleep deprived.

Interestingly, when the researchers sprinkled some food into the tank, the jellies became active again.

“It’s like the odor of coffee permeating your consciousness in the morning,” Sternberg says in a statement. 

Finally, the biologists gave the jellyfish melatonin, which is the hormone associated with sleep onset and a common drug which people take to doze off faster. The substance knocked the jellyfish out, the team reported in the journal Current Biology, with massive implications for sleep research.

“It’s important,” Sternberg said, “because it’s [an organism] with what we think of as a more primitive nervous system. … It raises the possibility of an early evolved fundamental process.”

While jellyfish don’t have a brain, they do have a ring-shaped nervous system embedded inside their bell-shaped bodies. These most recent findings suggest that nerve cells or nerve clusters require time off as well. Even more interestingly, jellyfish, which are positioned very early on the tree of life, could hint that sleep is as old as life itself.

Comb jellie, the phylum Ctenophora, may have been the first creatures on Earth. Credit: Wikimedia Commons.

Comb Jellies may have been the first animals ever

Since 2008, scientists have debated which of the two came first: the sponge (Porifera) or the comb jelly (Ctenophora). A new thorough genetic analysis suggests the latter was Earth’s first animal out of which all other creatures evolved.

Editor’s note: while very similar, comb jellies technically aren’t jellyfish (subphylum Ctenophora vs phylum Medusozoa). The term ‘jellyfish‘ in this article refers to comb jellies. Thanks to Wastrel Way for pointing it out.

Comb jellie, the phylum Ctenophora, may have been the first creatures on Earth. Credit: Wikimedia Commons.

Comb jelly, the phylum Ctenophora, may have been the first creatures on Earth. Credit: Wikimedia Commons.

For more than a century, biologists generally agreed that the first creature to evolve on this planet was a sponge because it’s such a simple creature. The sponge doesn’t have circulatory, nervous, or digestive systems, and only needs water to flow through its pores to survive. After DNA was discovered, and much later when modern genetic sequencing tools appeared, the status of the sponge as the first animal in the world seemed even more cemented. One previous genetic analysis, for instance, showed most genes involved in complex processes are present in sponges. 

The sponge, however, isn’t the only ancient animal at the bottom of all modern creature’s lineage. In 2008, a family-tree study pointed out that the comb jellies came before the sponge, and ever since scientists have been locked in a debate. A recent study which attempted to resolve the early diversification of animal lineages used a massive 1,719-gene dataset with dense taxonomic sampling and found evidence supporting the idea that sponges represent the sister group to all other animals.

While impressive, Antonis Rokas, a biology professor at Vanderbilt University, cautions that such ‘big data’ analyses can still pose phylogenomic contradictions.

“This has worked extremely well in 95 percent of the cases, but it has led to apparently irreconcilable differences in the remaining 5 percent,” Rokas said in a statement.

In a new paper published in Nature Ecology & EvolutionRokas and colleagues employed a new approach to settle 18 controversial phylogenetic relationships, among them the ‘sponge vs comb jellyfish’ debate. In total, the study included seven relationships from animals, five from plants, and six from fungi in order to figure out why so many studies have come up with such conflicting results. To get to the bottom of things, the researchers painstakingly compared the individual genes of the leading contenders in each relationship. That’s hundreds of thousands of genes.

“In these analyses, we only use genes that are shared across all organisms,” Rokas said. “The trick is to examine the gene sequences from different organisms to figure out who they identify as their closest relatives. When you look at a particular gene in an organism—let’s call it A—we ask if it is most closely related to its counterpart in organism B? Or to its counterpart in organism C? And by how much?”

By determining which genes weighed more for a particular hypothesis, like ‘comb jelly came first’, and by labeling the resulting differences as a ‘phylogenetic signal’, the team determined that the comb jelly has significantly more genes which support its ‘first to diverge’ status than the sponge.

Besides jellyfish vs sponges, the researchers also addressed other phylogenetic conflicts like whether crocodiles are more related to birds or turtles. Using the same method, the researchers found 74 percent of the shared genes indicate that crocodiles and birds form sister lineages while turtles are just close cousins.

As to why previous efforts turned out to be so controversial, Rokas suggests the statistical methods used by evolutionary biologists are influenced by ‘strongly opinionated genes’. Only a handful of such genes, which have a strong phylogenetic signal for one of the specific hypotheses, pop up in studies, but these are enough to skew results. For instance, in the case of another controversy surrounding flowering plants and modern birds, the researchers found that removing a single opinionated gene flipped the results from one candidate to another. In this particular case, the team published an inconclusive result either because the available data is inadequate or because the diversification occurred too rapidly to resolve.

“We believe that our approach can help resolve many of these long-standing controversies and raise the game of phylogenetic reconstruction to a new level,” Rokas said.

Of course, that’s not to say this is the final word on the matter. As outlined earlier, it was only in March that a comprehensive genetic analysis gave credence to sponges as the ‘first to diverge’ in favor of the jellyfish. It’s likely that the two will switch roles multiple times before biologists reach a satisfying method. It’s amazing, however, that out of the millions of species that lived on Earth we’re able to single out only two main candidates. That, in itself, is a testimony to how powerful science is.

Fresh spores of Myxobolus nagaraensis. How fitting that these look like alien heads since by all means they evolved so. Photo: T. Kageyama

Jellyfish degenerates into mucus parasite: another amazing quirk of evolution

What’s an animal? That’s a harder question to answer than ever, given scientists found a group of microscopic parasites called myxozoans made up of just a few cells are in fact jellyfish. These look nothing like jellyfish, mind you, but the genetic analysis is unambiguous: these are still jellyfish.

Fresh spores of Myxobolus nagaraensis. How fitting that these look like alien heads since by all means they evolved so. Photo: T. Kageyama

Fresh spores of Myxobolus nagaraensis. How fitting that these look like alien heads since by all means they evolved so. Photo: T. Kageyama

According to Wikipedia, animals are multicellular, eukaryotic organisms of the kingdom Animalia. All animals are motile, meaning they can move spontaneously and independently, at some point in their lives. Yet again, we have these little buggers. “Animals are usually defined as macroscopic multicellular organisms, and this is not that. Myxozoa absolutely redefines what we think of as animal,” said Paulyn Cartwright of the University of Kansas.

Myxozoans make up a diverse group of more than 2,100 parasites. These usually plague commercial fish, and some parasite infections cause lethal effects. Non-lethal effects can include the production of small but obvious white cysts in the muscle that make fillets unsightly, unappetising and therefore unmarketable. Oddly enough, when the myxozoans reach the brain and spinal chord of trout and salmon they cause whirling disease which compel the fish to swim in circles. Peculiar beasts, but also elusive since it’s not clear how the myxozoans evolved.

Some have proposed these have evolved from single-celled organisms, but later DNA sequencing showed they were animals, or almost so. Almost since myxozoans lack the Hox genes, essential for embryonic development in animals.

Though they lack a gut and mouth, the structure of the myxozoans is complex resembling the  cells of cnidarians – a group that includes jellyfish, corals and sea anemones. What Cartwright and colleagues found after they sequenced the genomes of two distantly related myxozoan species is that these are in fact cnidarians.

Their genomes are 20 to 40 times smaller than a jellyfish. At  20 million base pairs, it’s actually one of the smallest genomes ever reported in an animal. For comparison, the human genome numbers  3 billion pairs of bases.

What we’re witnessing is retrograde evolution. Typically, an organism evolves from simplicity to complexity, but the reverse process happened to the myxozoans. In time, the myxozoans shed a lot of DNA and turned into a lesser organism. Perhaps, they weren’t parasites to begin with.

This may be the first known case of simplification from a macro to a microorganism, a cheap trick which evolution likely used more than once though.

“First, we confirmed they’re cnidarians,” Cartwright said in the statement. “Now we need to investigate how they got to be that way.”

“It would be hard to recognize such animals because they would look so different from their closest relatives,” Cartwright said. “I think with new technologies such as whole-genome sequencing, we can better identify the evolutionary origins of some of these strange creatures.”

The moon jellyfish move ther remaining limbs around to become symmetrical again. Image: Michael Abrams and Ty Basinge

Moon Jellyfish morphs back into symmetry after losing limbs

A novel, previously unseen self-repair mechanism was reported by a team of researchers at Caltech who studied the moon jellyfish. A lot of animals, mostly invertebrates, grow back their lost limbs after these are bitten off by predators or lost in an accident. The moon jellyfish, however, employs a different tactic altogether: instead of expending a lot of energy to regrow its lost limb, the animal re-arranges the limbs it has left to regain symmetry. Even when it’s left with two limbs out of its initial eight, the jellyfish will still re-arrange itself. This sort of mechanism might prove extremely useful in designing self-repairing robots.

Back in symmetry

The moon jellyfish. Image: Terra Spirit

The moon jellyfish. Image: Terra Spirit

Aurelia aurita or the moon jellyfish is one of the most common jellyfish species in the world. It’s translucent, usually about 25–40 cm and easily recognizable by its four horseshoe-shaped gonads visible at the center of the bell. It’s remarkable though that given the animal has been widely studied, it’s only recently that we learn of its unique self-repair ability.

“We’ve now observed another self-repair mechanism,” says researcher Michael Abrams of the California Institute of Technology (Caltech), a graduate student in biology and biological engineering. “It kind of broadens our definition, a little bit, of self-repair.”

Abrams and colleagues focused on larval moon jellies, known as ephyrae. During this stage, the juveniles only measure 1cm in diameter, but they’re limbs look and behave just as in the adult stage. Typically, the moon jellies are born with eight limbs arranged in a radial pattern.

Initially, the researchers wanted to see if the jellyfish could regrow its lost limbs, like other invertebrates. So they amputated one or several limbs from anesthetized ephyrae then introduced them to their familiar salt water environment. The jellyfish didn’t regrow the lost limbs, but instead behaved far more remarkably.

The moon jellyfish move ther remaining limbs around to become symmetrical again. Image: Michael Abrams and Ty Basinge

The moon jellyfish move ther remaining limbs around to become symmetrical again. Image: Michael Abrams and Ty Basinge

In the image above, the top row shows the process of symmetrization after losing four of eight limbs. The bottom row shows the same process after losing five of eight limbs. Basically, the symmetrization occurred with whatever limbs the jellyfish had left, even just with two.

“Pretty quickly, we realized that they were doing something very different than what anyone had ever talked about before,” Abrams says.

The jellyfish likely adapted this feature because symmetry is essential to its survival. The symmetrical limbs act like paddles which help the animal swim and pull food towards the central mouth. “And you can imagine how this paddling surface would be disturbed if you have a big gap between the arms,” Abrams said.

To study how the moon jellyfish re-arranges itself, the researchers used a cell proliferation stain to track cell death and birth. Even more surprising, the animals didn’t use cell growth or shrank parts to re-purpose itself. Instead, most likely the pulsing of the muscles is behind the mechanism. As the creatures swims about, it pulls the remaining arms into new positions. When they put this hypothesis to the test by applying muscle relaxers, the amputee jellyfish were unable to regain symmetry, as reported in PNAS.

Remember, all of this happen inside a creature with no brain! Robots, aren’t that far behind so this neat trick might be helpful. A damaged robot can’t grow back a mechanical part, put it can sure reconfigure itself to become functional again. The moon jellyfish might serve as an example.

Comb jellies could be the earliest ancestors of all animals

With their eerie, translucent and soft bodies, their translucent and intricate shapes and bizarre bioluminescent displays, comb jellies are among the biggest beauties and mysteries in the oceans. Now, according to a biologist from Vanderbilt University, these delicate marine predators have another important story to tell about the origin of animals; a 550 million year old story.

Ctenophore Bolinopsis infundibulum. (Wikipedia Commons)

Comb jellies are part of a genus called Ctenophora (Greek for ‘comb bearers’). You wouldn’t guess it, but Ctenophores, variously known as comb jellies, sea gooseberries, sea walnuts, or Venus’s girdles, are voracious predators.

Antonis Rokas reflected on the significance of the first successful sequencing of the genome of the genus, conducted by Andreas Baxevanis at the National Human Genome Research Institute – the sea walnut, an aggressive species that invaded the Black Sea in the 1980s. Based on a very thorough analysis of the sea walnut genome, Baxevanis and his team came to the conclusion that ctenophores are the oldest relative of the entire animal family, including humans.

Sea walnut at the Boston Aquarium. (Wikipedia Commons)

His results seem pretty convincing, but the only problem is that the study contradicts several other convincing studies as well. As a matter of fact, not one, but several other studies grouped comb jellies together with jellyfish, and concluded that sponges are the oldest animal relative, despite their sedentary nature.

But Rokas, who has studied many directly conflicts between well-documented phylogenetic studies says it is not really a surprise to find contradictory tree-of-life studies. The branchings that gave rise to the lineages that eventually became the sponges, ctenophores and jellyfish took place in a narrow window of time a long time ago – it’s these conditions that are very hard to map.

But even if he is right or wrong, it’s clear that we have to consider the addition of comb jellies to existing knowledge of the earliest animals and their closest relatives.

You can’t really choose your relatives or ancestors… but when it comes to it, I’d choose a ctenophore over a sponge.

Via Vanderbilt University.

Developing a flying, jellyfish-like machine

It’s been previously shown that the jellyfish are the world’s most efficient swimmers, and researchers wanted to see if they could implement some of its features into a flying machine.

New York University researchers have built a small vehicle whose flying motion resembles the movements of a jellyfish – possibly paving the way for small aerial robots which could be used for surveillance, traffic monitoring, or even search-and-rescue, while spending a minimum amount of energy.

It’s not the first time scientists have tried to mimic what’s going on in nature and implement it in a flying machine – inspiration was drawn from fruit flies and moths, for example. However, the problem is that the flapping wing of a fly is inherently unstable, raising major structural issues. Now, Leif Ristroph of NYU believes he has found the solution.

The prototype he’s created is limited: it can’t steer (pretty much like a jellyfish), and it’s relies on an external energy source – but the proof of principle has been made. What he developed is called an ornithopter (something which Dune fans might find familiar) – a flapping-wing aircraft. Ornithopters offer an alternative to helicopters in achieving maneuverability at small scales, although stabilizing such aerial vehicles remains a key challenge. The robot he developed achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. It measures only 8 cm, and its wings are arranged in a flower-like pattern.

The main purpose of this type of research is to make these robots as small as possible, and as simple as possible – so they can sneak in through tight spaces, without being observed and/or without disturbing.

“And ours is one of the simplest, in that it just uses flapping wings.”, says Ristroph.

Scientific Reference:

Japanese Fishing Net (Credit: Shin-ichi Uye, Hiroshima University)

Inevitable Invasion? The Coming of the Jellyfish

Healthy wildlife populations aren’t always good news.

Global jellyfish populations are surging and marine scientists are sounding alarms – some of them dire. Biologist Lisa-ann Gershwin, author of Stung! On Jellyfish Blooms and the Future of the Ocean, states that jellyfish could displace Antarctic penguins, devastate world fisheries, and even starve whales to extinction.

Are things really that serious? There’s plenty of evidence that jellyfish invasions (or “blooms”) inflict significant damage on ecosystems and economies and that blooms are increasing. Unfortunately, science is finding that these problems are largely effects of . . . us.

Not on anyone’s endangered list

Jellyfish are well-designed for surviving changed conditions. Their bodies are more than 95 per cent water, so growing doesn’t increase metabolic demands as much as it does in more complicated creatures.

Jellies are also unique in their ability to reduce their body size when food is scarce and to grow again when food is plentiful. Their lower metabolic rate also means a low oxygen requirement, which can be very useful in polluted waters

And jellies can eat just about anything, including young fish, fish eggs, and plankton. Their diet that can decimate fish populations and, because plankton remove carbon dioxide from the water, their diet can contribute to climate change.

Japanese Fishing Net (Credit: Shin-ichi Uye, Hiroshima University)

Japanese Fishing Net (Credit: Shin-ichi Uye, Hiroshima University)

Such adaptability has paid off. Today, there are 1,000 – 1,500 known types of jellyfish. Jellies and their phylogenetic cousins represent up to one third of the world’s marine biomass and, in some regions, they exceed fish biomass more than three to one.

Jellyfish may be the tribbles of the ocean.

We’re here to help

While jellyfish come with all the right tools for success, humans make things a lot easier for them. Piers, oil platforms and floating trash, for example, serve as ideal jellyfish nurseries, providing the good anchoring surfaces that polyps need for growth.

Human activity also provides useful transportation. Jellies travel in the ballast water of ships and are dropped off in new ports when that water gets dumped. An even easier way to catch a ride is on the hulls of ships (known as “hull-fouling”). In fact, ships may be responsible for almost 70 percent of the transport of non-native marine species around the world.

Jellyfish Cluster (Wikimedia Commons

Jellyfish Cluster (Wikimedia Commons

Even land activities work to tilt the survival advantage in favor of jellies. Fertilizers and other runoff can strip oxygen from sea water (a process known as eutrophication) but, because jellyfish tolerate low oxygen better than other marine animals, they can thrive to the detriment of almost everything else.  Jellies can be found in some seas that are otherwise “dead zones” from fertilizer runoff.

The most direct effect of human activities is probably overfishing, which simply removes jellyfish predators and competitors from the environment. Jellyfish blooms seen in the Black Sea and off of South Africa, for example, were likely due to overfishing of anchovies, which would otherwise compete with jellies for food.

A lack of good data

The consequences of jellyfish blooms would seem to be increasingly easy to identify. The salmon killed by the 2008 jellyfish bloom near Northern Ireland, for example, were valued at $2 million. Jellyfish eventually caused the complete collapse of Black Sea anchovy and sardine fisheries by devouring the fish’s food, their eggs, and their young. Power plants in Scotland, Japan and Israel have also been temporarily shut down when jellyfish clogged their cooling-water intake systems.

The problems would seem to be growing increasingly urgent, too. Fears that jellyfish are taking over the oceans have escalated in the past decade with increasing numbers of bloom reports. The clearest stories may be the Nomura jellyfish blooms off Japan: While only three blooms were recorded between 1920 and 1995, six blooms were recorded between 2002 and 2010. Not an encouraging trend.

Despite anecdotes and field reports, however, not everyone is ready to predict calamity. Some scientists don’t believe that there’s yet enough solid data to characterize a problem or to design countermeasures. Consequently, they’re now trying to fill some of the holes in the data record with new programs and new technologies. Citizen scientists are also being recruited to aid in the effort to expand our knowledge of jellies.

Jellyfish are believed to be at least 500 million – 700 million years old. That they preceded most other creatures in the sea and are still thriving today is reason enough to respect the hazard that jellies present if they continue to move and displace other species. Science is concerned but not panicked.

It’s rare to see the effects of common human activities align so conveniently to “aid” a part of nature. While future activities may change things, jellies seem built to take advantage of all we have to offer them today.

Why a jellyfish is the ocean’s most efficient swimmer [with video]

Jellyfish are really impressive creatures, for all their simplicity; now, a new research has shown that the elastic body allows moon jellyfish to travel extra distance at no energy cost.

A spinning vortex of water creates a region of high pressure (red/orange) under the jellyfish.
(c) BRAD GEMMELL

The sockeye salmon is a sleek, muscular torpedo which rams up waterfalls. The jellyfish is a blob, drifting on aimlessly in the oceans. Obviously, the salmon is the more powerful swimmer, but as it turns out, the jellyfish outclasses it in terms of efficiency – it outclasses everybody, for that matter. For its mass, the jellyfish spends less energy to travel a given distance than any other animal in the world.

Brad Gemmell at the Marine Biological Laboratory in Woods Hole, Massachusetts, has found that for all its lack of brain, the jellyfish is incredibly well adapted to its environment; it has a unique technique through which it recaptures some of the energy spent on each swimming ‘stroke’, giving itself an extra push without any cost, travelling further without any additional effort.

He first started studying the jellyfish as part of a US Navy-funded project to look at unusual methods of locomotion in marine animals. As he was analyzing their movements, he found something suspicious – sometimes, even when their bodies were perfectly still, they still picked up speed. This was so strange that he first discarded it as a measurement error.

“We first discounted these blips, but every species and every run we looked at had them,” he says. “They clearly weren’t noise in the data.”

To further study this speed boost, he paralyzed the jellyfish with magnesium chloride solution, which blocks nerve signals from reaching their swimming muscles. He then pushed them around with a rod to see how water moves around them.

What he found was that when the jellyfish contract their umbrella-like bells, they create two vortex rings – two “doughnuts” of water which spin onto themselves; the jellyfish initially propels itself by shedding the first ring, which is normal and not unusual. But as the bell relaxes, the second vortex of water spins faster and moves in, pushing up against the centre of the jellyfish and giving it a secondary boost, propelling the jellyfish “an extra mile” (see video above). The bell is so elastic that it relaxes automatically, which means that the extra boost comes at no extra energy cost.

These results contradict the typical view of jellyfish as inefficient swimmers, and with further studies and experiments, they could be applied for man-made vehicles as well.

“You could deploy them for longer without extra batteries, size or maintenance,” he says.

Source: Nature doi:10.1038/nature.2013.13895

Medusoid

Synthetic jellyfish made from rat heart cells can swim like the real deal

A team led by researchers at the California Institute of Technology (Caltech) and Harvard University have built this remarkable display of modern bioengineering – a completely engineered jellyfish that blends both living and non-living parts, masterfully fitted together. Called the medusoid, this cyborg jellyfish was created using silicone and muscle cells from a rat’s heart, and surprisingly, it can move and behave exactly like its living, biological counterpart, as seen in the video above.

“Morphologically, we’ve built a jellyfish. Functionally, we’ve built a jellyfish. Genetically, this thing is a rat,” says Kit Parker, a biophysicist at Harvard University in Cambridge, Massachusetts, who led the work.

MedusoidJellyfish are believed to be the oldest multi-organ animals in the world, possibly existing on Earth for the past 500 million years. They can swim with rhythmical contractions of the bell (muscles) that propel it with the force of the water pushed from inside the bell, sort of like jet propelling does with air jets, the action creates an equal and opposite reaction. This is very similar to how the human heart functions at a principle level, making it a viable candidate to model and analyze for tissue engineering purposes.

And Parker along with colleagues from the lab, where they work on creating artificial models of human heart tissues for regenerating organs and testing drugs, didn’t waste one moment after recognizing the jellyfish’s potential.

“It occurred to me in 2007 that we might have failed to understand the fundamental laws of muscular pumps,” says Kevin Kit Parker, Tarr Family Professor of Bioengineering and Applied Physics at Harvard and a coauthor of the study. “I started looking at marine organisms that pump to survive. Then I saw a jellyfish at the New England Aquarium, and I immediately noted both similarities and differences between how the jellyfish pumps and the human heart. The similarities help reveal what you need to do to design a bio-inspired pump.”

The scientists enlisted Caltech biotechnology researcher Janna Nawroth  for their jellyfish-emulating cause.  Nawroth performed most of the experiments, including the mapping of every cell in the bodies of juvenile moon jellies (Aurelia aurita), indispensable to understanding the animal’s propulsion system.

The team looked at an array of possible materials they could use to fashion their synthetic jellyfish; eventually they settled for a silicone polymer that makes up the body of the Medusoid into a thin membrane that resembles a small jellyfish, with eight arm-like appendage. The scientists then grew and applied  a single layer of rat heart muscle on the patterned sheet of silicone.

The swimming behaviour of the Medusoid closely mimics that of the real thing

The swimming behaviour of the Medusoid closely mimics that of the real thing

The medusoid was inserted in an electrically conducting container of fluid and  placed between two electrodes. The current was oscillated  from zero volts to five volts, and the medusoid began to swim with synchronized contractions that mimic those of real jellyfish.

“I was surprised that with relatively few components—a silicone base and cells that we arranged—we were able to reproduce some pretty complex swimming and feeding behaviors that you see in biological jellyfish,” says John Dabiri, a bioengineer who studies biological propulsion at the California Institute of Technology (Caltech) in Pasadena. “I’m pleasantly surprised at how close we are getting to matching the natural biological performance, but also that we’re seeing ways in which we can probably improve on that natural performance. The process of evolution missed a lot of good solutions.”

Parker says his team is taking synthetic biology to a new level. “Usually when we talk about synthetic life forms, somebody will take a living cell and put new genes in. We built an animal. It’s not just about genes, but about morphology and function.”

The team’s next goal is to design a completely self-contained system that is able to sense and actuate on its own using internal signals, as human hearts do. “You’ve got a heart drug?” says Parker. “You let me put it on my jellyfish, and I’ll tell you if it can improve the pumping.”

The findings were reported in the journal Nature Biotechnology.

Robojelly with uniform bell in water

Robot jellyfish that runs on hydrogen can swim forever in the ocean

After a three year effort, researchers at Virginia Tech have successfully managed to create a silicone robot that functions underwater by mimicking the  motion of a jellyfish. The robot can propel itself thanks to the heat-producing reactions catalyzed by its surface, and since it uses hydrogen and oxygen found in the water as fuel, the Robojelly can theoretically swim indefinitely in an ocean.

Robojelly with uniform bell in water

Robojelly with uniform bell in water. (c) Virginia Tech

The Robojelly’s platinum-based surface catalyzes the hydrogen in exothermic reactions which generate heat. This is heat is then transferred to the robot’s actuators which replicate the real jellyfish’s muscles; circular artificial muscles contract the bell, the jellyfish’s quasi-head cap, thus expelling water and propelling the contraption forward.

The actuators are made out of Bio-Inspired Shape memory Alloy Composites (BISMAC) – nickel-titanium shape memory alloy wrapped with multi-wall carbon nanotube sheets which are themselves coated with a catalytic platinum powder. The byproduct of the hydrogen reaction is vaporized water, completely harmless to the environment.

“To our knowledge, this is the first successful powering of an underwater robot using external hydrogen as a fuel source,” said Yonas Tadesse, lead author of a Robojelly study

The Robojelly has been in development since 2009, and has received funding from the Office of Naval Research. This vehicle will have a broad range of applications for both military and civilian uses. Most likely, the study will pave the way for the deployment of unmanned surveillance submarines. Check out a video of the Robojelly in action below.

The findings were reported in the journal Smart Materials and Structures.

source

Leatherback turtles get sanctuary on US coast

Federal regulators have designated almost 42,000 square miles of ocean as critical habitat for the leatherback turtles, the largest turtles in the world; even though this is a much welcomed initiative, the surface is far, far less than environmentalists and biologists were expecting.

A haven for turtles

This protected area is the first of its kind in the US, providing a needed haven for these turtles, which swim over 6.000 miles every year to eat jellyfish near the Golden Gate. The designation made by NOAA (National Oceanographic and Atmospheric Administration) was, in fact, a bittersweet victory for the people who have been fighting to protect these marine creatures from extinction; the main problem is that the 41,914 square miles that the NOAA’s National Marine Fisheries Service protected along the coasts of California, Oregon and Washington don’t include any migration routes, which are crucial for the survival of the species.

“It’s a big step in the right direction, but we want protections for migratory pathways,” said Ben Enticknap, the Pacific project manager for Oceana, an international nonprofit dedicated to protecting the world’s oceans. “I guess we’ve got a lot more work to do to get there.”

How the sanctuary works

The measure will restrict any projects that can harm the turtles or the jellyfish delicacies they devour. This includes, but isn’t limited to regulating agricultural waste, pollution, oil spills, power plants, oil drilling, gas exploration, etc. Aquaculture, tidal and wave turbines will have to take this in consideration as well in their building plans.

The measure, however, didn’t come as a benevolent act, but rather as a response to a lawsuit filed in U.S. District Court in San Francisco in 2009 by the nonprofit environmental groups Turtle Island Restoration Network, the Center for Biological Diversity and Oceana. They accused the government of failing to protect the reptiles from fishing, oil drilling and a variety of other activities.

Still in danger

“Threats to these turtles are increasing, not diminishing,” said Shore, whose organization also goes by its Web name, SeaTurtles.org. “We don’t want to see the leatherback turtles go the way of the grizzly bear and disappear.”

Leatherbacks, known scientifically as Dermochelys coriacea, are the largest sea turtles in the world, measuring up to 3 meters and weighing over 500 kilograms in some cases. Biologists believe they live somewhere between 40 and 100 years. The worldwide population of the leatherback turtles has declined by over 95% in just 30 years, and this steep decline continued; hopefully, this measure will change things.

Aside from the above mentioned issues, the reptiles face another threat: plastic bags, which look just like the jellyfish they eat. A recent study concluded that almost 40% of all leatherback turtles found dead had plastic bags in their intestinal tract.

The deadliest creature in the world

So, microorganisms and other humans aside, what do you think is the deadliest creature in animal kingdom? A snake, perhaps a lion or bear, a scorpion perhaps? Neah, not even close. The deadliest creature in the world is actually called a sea wasp.

sea-wasp

Specialists use the term ‘deadliest’ when they refer to venomous creatures, that produce toxins that can be harmful or deadly to other animals or humans. When they make this ‘top’, they take into consideration two things:
– how many people can an ounce of the venom kill; and
– how long does it take to die from that venom.

For both of those things, the undisputed winner and (as far as we know) all time record holder is the sea wasp. Don’t let the name fool you, because the sea wasp is actually a jellyfish (we’ve been having a lot of those lately); on each tentacle, they have about 500.000 nematocytes. Nematocytes are basically needles that inject venom in everybody that happens to tocuh them.

cironex

They actively hunt their prey and they’re quite fast swimmers for jellyfish (5 mph), but are not aggressive and they try to avoid humans. What’s interesting is that turtles are not affected by their venom and actually eat these jellyfish (nature sure has its ways).

osgok-00001316-001box-jellyfish-or-sea-wasp-poisonous-australia-posters

If (and we hope not) you would get stung by such a jellyfish, a bottle of vinegar and a first aid kit may very well save your life. Here’s how it goes: pour vinegar over the stung areas. The pain is almost unbearable and vinegar won’t help with that, but it will render the nematocysts that haven’t ‘fired’ harmless. If you attempt to remove the tentacles, it’s very possible to activate them and do even more damage. It’s quite safe to say that vinegar has saved dozens of lives, especially on the Australian beaches.

Giant files: Nomura and Lion’s mane jellyfish

The Nomura Jellyfish

3084070830122111Nomura Jellyfish are a large species of Japanese jellyfish, that seems to be giving them some big headaches. They can grow up to 2 meters in diameter and usually weigh over 200 kilograms, going up to 220 in numerous cases and they spawn in the seas between China and Japan, invading the Japanese shores for 4 years now.

jellyfish_invasionSince then, they’ve become such a problem that a commitee has been formed just for them, and researchers have been trying to promote them as a novel food. Students in Obama, Fukui (Japan) have managed to turn them into a sort of tofu, and they also managed to extract colagen, which is beneficial for the skin.

jellyfish_nomStings are generally very painful, but do not cause major damage. Just 8 deaths have been caused by stings from the Nomura Jellyfish. So what caused this species to grow so large, even 100 times bigger than the average jellyfish? Scientists have been able to come up with a few theories, and there’s a big possibility that all these theories work together:

  • – China’s new dam, Three Gorges Dam on the Yangtze river is the biggest hydroelectric project. It also increased the amount of phosphorus and nitrogen in the waters off China, which is just what the Nomura jellyfish look for in a breeding ground.
  • – Also, it is possible that the waters have been enriched in nutrients due to the activity of farms.
  • – The third theory is again linked with Chinese activity, especially with the development of ports and harbours, which are structures the larvae attach themselves to.
  • – It could be that due to global warming the waters are heating and the waters are becoming more acidic, making it a better environment for jellyfish.
  • – The last theory is that China has overfished their waters and eliminated the predators that fed on the larvae

nomura27s20jellyfish_1

Even with the full help of the government, the Japanese have found it very hard to come to terms with these giants. Of course they aren’t immortal, but the problem is that whenever they feel under attack or threatened, they release billions of sperm or eggs which attach to corals or rocks and when conditions are favorable, they detach and grow into more jellyfish.

Lion’s mane jellyfish

177430711_fokyg-s-1Jellies have been around for almost 700 million years, making them older than the dinosaurs. They are very simple yet effective creatures, possessing no bones or cartilage, no blood and no heart and also no brain! As a matter of fact, they are made up of 95% water.

capillata2

However, the Lion’s mane jellyfish may just be the longest animals in the world. In 1870, off the shores of Massachusetts Bay, locals found a washed up specimen that had a diameter of 2.3 meters and its tentacles were 36.5 meters long, longer than a blue whale!

lionsmane1

The tentacles are covered with millions of stinging capsules contained within the cells from the tentacles. This jelly, like many others, is a predator and captures its prey with the venom from the capsules. The venom is very powerful and could be fatal to humans, but in most cases, it’s not. It also lives in very cold waters, even in the arctic areas, and cannot cope with warmer waters so don’t expect to meet them when you go swimming anytime soon.

lionsmane2

Image source. Photographer: Tim Nicholson

They frequently grow over 2 meters in bell diameter and 30 meters in length, at the end of each summer. Fortunately, by that time, they are rather uncommon.