By Ricardo Sunico
Ateneo de Manila High School
Most kids start out liking gelatin. But later on, there are other "jellies" out there which are not to their liking.
In the depths of the ocean, or at least right under its surface, dwell thousands of different jellyfishes. Jellyfishes are from the phylum Coelenterata, the same group as corals, a group of mostly "baglike" creatures.
Jellyfishes stand out from all of the other coelenterates due to the complexity and beauty of their structure. It's not that their bodies are composed of very complex organelles. In fact, some jellyfishes, due to their free-floating nature, are classified as zooplanktons. But the jellyfish do have complex parts,and one of these is its tentacles.
Jelly-Groups
The jellyfish generally comes in two main pelagic groups. They are the medusae and the siphonophores. Though they seem almost identical, they are really quite different.
Medusae
Medusa in Greek mythology was a Gorgon and a fierce monster who had a woman's body, a snake's tail and a hair full of serpents. Her stare could turn men to stone.
Most likely the first scientists named these jellyfishes after the way their tentacles looked. The numerous tentacles of the medusae were very much similar to the head of serpents possessed by the Gorgons. Another good reason could be that these jellyfishes do have ferocious stings that can result in minor irritation to paralysis and death.
The main difference between a medusae and a siphonophore is their reproductive cycle. Medusaes start out by forming eggs that later on develop into tiny larva with small hairs, also called the cilia, for transportation. They swim off a short distance until they reach a rock or coral formation and settle. Now this is the strange part.
Jellyfishes seem to carry on a strange existence in two main forms. They spend their adult life as the free-swimming, sexually reproductive medusaes, but as offsprings in their primitive state, they are in the form of polyps. The word polyps is from a French term meaning octopus although polyps have nothing in common with the octopus.
They would most likely resemble some sort of miniature sea anemone. It then grows and it's "trunk" becomes longer. A series of furrows begin to develop until they soon cut into it entirely, forming different saucers or discs which later on separate into little jellyfish which will develop into their adult counterparts and continue the cycle.
Some examples of Medusaes are the Periphylla that are about two to three feet in diameter, the Rizostoma which are roughly the size of a soccer ball and there's the highly poisonous Cyanea which are about six to seven feet in diameter and whose deadly tentacles dangle beneath it at close to 120 feet.
Siphonophores
Siphonophores are different in the fact that they stay partially above water. They have an outcropping of tissue that acts as a sail to propel the jellyfish to other feeding grounds. An example of a siphonophore is the Velella or before the wind sailor. They are "colonies" of sort, composed of several main components and other minor parts in charge of reproduction and food procurement. Throughout their travels, they must periodically wet their sails which is a purely instinctive action.
One of the most popular kind of jellyfishes is the Portuguese Man of War. This creature, also known as the Physalia has a powerful sting which can give a man hours of maddening pain. It's tentacles are very versatile. They can be pulled back into stubs or left to drag over 100 feet below the beast.
Scientists have said that the Physalia's poison can be compared to a cobra's venom. Despite its ferocious reputation, there have been very few incidents of death by the Physlia's sting. These were mostly small children. There are, of course, jellyfishes who have killed both children and adults.
Deadly Stings
There are certain species of jellyfish whose poison is deadly to man.
The most often reported are the Lebenema and other Pacific species more commonly called sea wasps, fire medusae and box jellies. They are most often reported off Darwin in Northern Australia. Most of the information on these poisonous varieties come from Dr. R. V. Southcoat, a physician and a zoologist.
The great danger in these jellyfishes is the speed in which their poison is spread throughout their victims. Some stings bring death in a matter of hours, others in mere seconds.
The most dangerous jellyfish remains to be the Chinorex fleckeri from the Cubomedusae family. It is light blue in color and is roughly the size of a coconut. It swims with the greatest stealth such that it barely creates a ripple in the water. And due to its color, it is practically invisible.
Another jellyfish which is extremely similar to the Chinorex is the Chirosalmus quadriatus. It is practically identical to the Chinorex and just as deadly. This devil of the deep has killed dozens in the waters of the Philippines, Borneo and Malaya.
Tentacles
The greatest features of any jellyfish are its tentacles and the venom it contains. The sheer complexity of the jellyfish's stinger is astounding. Its poison acts as a defense mechanism and as a means of aquiring its food. The jellyfish is definitely a predator.
The entire mechanism is contained within a single cell. It is composed of a trigger hair, numerous spines, a thin tube coiled within the bulb and a bulb of liquid housing the entire unit and its poison.
What happens upon activation of the trigger is as follows:
The slightest sensation upon the trigger hair results in the activation of the entire unit. The pressure inside the bulb shifts so that the spines extend, such like blowing air into a rubber glove. The spines puncture the flesh of the victim and due to the pressure, the tube extends into the laceration. Immediately, the poison is released and the victim, either fish or man, will be subjected to the effects of the deadly venom. This would either result in irritation, paralysis or death.
A strange thing that has been encountered is the defense system of the octopus Tremoctopus violaceus who has been seen to carry Physalia spines on it's tentacles. Nobody knows what the creature must have gone through to acquire these spines, but the structure of its tentacles seemed to be designed to accept the spines.
Jelly-Condos
One of the strangest things about the jellyfish is the fact that despite the danger its poison bears, there are many fishes who risk their lives living around the these creatures.
Often seen beneath the Cyanea are baby Whitin, young horse mackarel, butterfish and haddock fish. These fishes seem not to care that they swim amongst the tentacles of one of the most poisonous jellyfish around.
Others like the amphipod crustacian, Hyperia galba seem to thrive upon the extra food material around the jellyfish or even the mucus of the Cyanea.
Even the Physalia has it's own denizens such as the Nomeus ronovii. This fish is rarely seen anywhere but with the Physalia, zipping between its tentacles. It has a pattern of light blue streaks against a silver background, causing it to blend with the jellyfish's own tentacles and keeping predators away from itself.
Despite the fact that Nomeus has the greatest resistance to the Physalia's poison, it too shares the fate of other fish its size. Death.
Deep Jellies
Some of the most magnificent jellyfishes dwell even deeper down in the ocean, beyond the feeding grounds of Physalia and Cyanea. Here, the jellyfishes no longer possess the colors of blue and purple to blend with the sea. As if for show, they've adorned themselves with mostly red colors and even chocolate brown.
Some jellyfishes like the Atolla, Agliscra ignea and the Halicreas rotundanum are bright red to attract their prey. Others like the Nausithoe rubra and the Periphylla hyacinthina are not only red but other shades of bright purple and darker tones of brown.
As with most creatures at these great depths, some jellyfishes have adapted themselves to carry their own luminence. One such jellyfish, the Pelagia noctiluca, is barely the size of your palm and yet burns with a light of its own making it seem like tiny star in the blackness of the sea.
These deep jellyfishes are truly some of the most beautiful creatures in the sea.