Nature's Hallucinations -- Behold The Jellyfish, A Lesson In Beauty, Minimalism, Languor And Menace
THERE ARE UNQUESTIONABLY beautiful animals in our Northwest, like the swallowtail butterfly. Lordly ones like the bull elk. Graceful ones, like the great blue heron.
There are ugly animals like the ratfish, and slimy and stinky ones like the slug and skunk.
And there is one group that is so ethereal, so unworldly, so bizarre and so elegant as to call into question all our assumptions about beauty - not to mention purpose, menace and importance.
We refer, of course, to our annual bloom of billions upon billions of jellyfish.
Here is a descendant from the dawn of life, pulsating like slow breath to some unheard evolutionary music, adrift but not aimless: In mere months, a jellyfish buds into being, explosively grows, spews eggs or sperm, and dies, all in cycle with the sun.
It becomes a Rorschach test of human reaction.
"Yucky!" one schoolchild yelled recently at their tank at the Seattle aquarium.
"Pretty!" another exclaimed.
"They look like clouds!"
"They look like snow!"
"They look like monsters!"
Here is a critter with which to contemplate what life is, or isn't.
Almost all animals move, feed and reproduce, of course, but it is the jellies that underline what an astounding array of body plans they use to do so.
How to explain to a Martian both the goat and the worm, the seagull and the whelk, the chipmunk and the octopus? How could natural selection account for such variety?
Simply put, every species has a successful strategy, a niche in the environment, and tradeoffs. Witness the speed of the fragile hummingbird vs. the gliding power of the eagle, the quickness of the rabbit and power of the bear, the patience of the reptile and industry of the beaver.
Animal bodies are lessons in physics. The spindly legs of the sturdy ant would snap if it were blown up to elephant size. The pounding heart of a tiny, thin-fleshed mouse would roast an animal with the bulk of a deer. A bird sacrifices sturdiness so it can soar.
Of all the animals, then, which is the most elegant? Which combines great beauty with utter simplicity, languid efficiency with minimal effort, delicacy with venom?
The jellyfish! It is a hallucination, a ghost, a wedding dress, a blowing curtain, an acid trip - one of the most common, ancestral, overlooked and lovely animals of our inland sea. It can fill the water like a division of paratroopers, glitter with bioluminescence like a chandelier, or undulate like an exotic dancer. It pumps its way through Puget Sound like the beat of an ancient heart.
Small wonder that one-time arts student Claudia Mills was drawn to the jellyfish while a student at the University of Washington's Friday Harbor Labs. After 20 years of study, she is one of the world's experts on a creature whose importance and ecological role is still barely understood.
"It was the visual appeal," she confessed. "They're just really cool-looking."
MOST OF US are animal snobs. We like critters like us, which means the ones with backbones: mammals, birds, fish, reptiles and amphibians. Yet 95 percent of the planet's animals do just fine without a backbone, thank you very much, and jellyfish are among the most basic of those.
You can count on both hands the number of people worldwide who study them extensively. Mills is one.
A jellyfish has no brain, no lungs or gills, no heart and no bones. It has a gossamer bell, stinging tentacles to collect food, a stomach, a few nerves to twitch the bell into pulsing, a few canals to deliver nutrients, and gonads to make egg and sperm.
That's it. Some jellyfish can sense light, but they have no eyes, nose, ears or tongue. You can't strip an animal down much more. While humans are 70 percent water, jellyfish are up to 98 percent.
Much of a jellyfish is truly jelly, a gelatinous goo that isn't even made of living cells, but gloppy stuff trapped between two cell layers: an outside "skin" and an inside lining of muscle that contracts the bell to provide propulsion. Between is bulk that isn't even "alive" in the conventional sense of the term.
Yet this simplicity has great advantages. Since they are mostly water, it takes few chemicals like carbon to make a jellyfish. Accordingly, they grow quite rapidly on little food. They are so like their environment they float with little swimming effort. Their watery mass means they make lousy food for predators - a "defense" that has served them well for nearly half a billion years. There's so little to them that their metabolism is slow, meaning they can drift long periods without eating. They're so simple that some jellyfish can regrow parts bitten off by enemies.
In other words, less is more.
Jellyfish act like living drift nets, their bell and tentacles catching prey from a large area relative to their size. They draw oxygen through their skin. Many are so transparent they are almost invisible - the ultimate camouflage. Most are tiny, but a few have been recorded with diameters of 8 feet or more, and tropical varieties sometimes grow tentacles in excess of 30 feet long. One in the arctic was found washed up with a seal skeleton in its stomach.
Their origin is obscure because jellyfish make lousy fossils, lacking bone or shell. They are believed to date at least as far back as the "Cambrian explosion," however, when complex animals first arose. If so, they far predate the dinosaurs, and this makes biological sense. If you wanted to start animal evolution with its simplest forms, a jellyfish is a good place to begin. Only sponges and corals are simpler.
Yet because of this simplicity they remain astonishingly successful. Like many marine species, jellyfish are seasonal, appearing in spring and dying off in fall. Most aren't noticed until late summer when the biggest grow to the size of a plate and bob past a boat or ferry like a floating fried egg. Yet when Mills kneels at her Friday Harbor dock in spring, water that first appears empty is shown to be filled with the gossamer parachutes of jellyfish no bigger than a quarter, feeding on tiny shrimp-like copapods that look like floating dust.
Our inland sea blooms with the returning sun like a field of wildflowers, and each spring uncounted billions of jellyfish bud into life to eat and be eaten in staggering quantities. We don't have a clue what this cycle of delicate goo means to the marine ecosystem we're spending a small fortune to protect.
For example, we know that pollack, the most important commercial fish in the North Pacific, hides among jellyfish tentacles when young to avoid other predators. We also know some jellyfish are capable of paralyzing and consuming very young pollack. We also know jellyfish are occasional prey of fish.
So is jellyfish presence good or bad, from the human point of view? We don't know.
ONE OF THE COOL things about jellyfish is that their beauty, like that of flowers, is linked to their reproduction. As they grow like translucent balloons, keeping time to their own inner music, they are preparing for sex.
"The adult jellyfish is really just a dispersal agent for egg and sperm," Mills explained. The adults come together in squadrons or schools, some male and some female, and deposit their DNA in the water for days in a row. Tide and current determine if the two unite and begin forming a small ball of cells.
These cells then settle to the bottom or onto a hard surface and form what is called a polyp, a tiny stalk-like creature that represents a jellyfish's winter cycle and somewhat resembles a tiny sea anemone, its near-cousin. Some polyps have hard surfaces and others are soft. Some form colonies, the tubes linking to help feed one another. Some root alone.
The hairy growth on boat hulls is, in part, jellyfish polyps. From each "hair," microscopic jellyfish bud in the spring, then break off and float away, growing as they eat plankton in the water. After reaching maximum size, there is another release of egg and sperm and the cycle starts all over again. Species of jellyfish follow one another in our waters like a cycle of flowers.
In the deep ocean, jellyfish polyps can grow on floating clumps of algae, on swimming snails or on the skin of fish. Some jellyfish spend their lives on the surface, and others swim thousands of feet deep.
Once started, polyp colonies in shallow water can persist for years, budding each spring.
Adult jellyfish are so unlike their polyp stage that many were originally classified as separate species. Biologists are only now getting around to linking each jellyfish species with its distinctive polyp.
AS BEAUTIFUL as jellyfish are, they are also scary. Few Hollywood aliens come close to a large jellyfish in menace, their slow beat as ominous as it is mesmerizing. Some tropical box-jellyfish species like the sea nettle or Portuguese Man of War can deliver a sting powerful enough to kill or seriously injure a human. A few Puget Sound kinds can be quite painful.
The tentacles of most local jellyfish are designed to capture small prey such as plankton and fish larvae, not gallumping whales like us. Nonetheless, tentacles often contain tiny, wicked-looking barbs that can fire paralyzing toxin into the skin of whatever it has come into contact with. The poisons can cause pain, swelling, burning and redness.
Their scientific names reflect this. One common subclass of jellyfish is called Hydromedusae, named for the Medusa, the mythical Greek monster with snakes for hair.
Many local jellyfish don't sting and none are lethal. The Hollywood producers of the movie "Sphere" called Mills to ask if it was plausible jellyfish could attack and kill a diver. When she said no, they thanked her and put it in the movie anyway.
Gelatinous animals are not easily generalized: The design is so successful that they extend beyond what we call jellyfish and fall into at least four separate animal phyla:
Cnidaria - What we recognize as jellyfish, and also including coral and anemones;
Ctenophora - Similar to jellyfish but with a globelike, instead of bell-like, body;
Mollusca - Swimming, jellylike, plankton-size snails without shell or foot, some of which flap "wings" and are called sea butterflies;
Chordata - These include sea squirts, cylindrical salps and tadpolelike plankton grazers, all with a primitive nerve cord. We humans are also in the Chordata phylum. If it's a little embarrassing that a sea squirt is a distant relative, that's evolution for you.
As many as half the species in the upper ocean are believed capable of producing their own light through a chemical reaction called bioluminescence, similar to that created by fireflies to attract mates. Many jellyfish are among them, some with a string of lights on their rim like landing lights on a flying saucer.
One common Washington jellyfish species is Aequorea, once harvested in Friday Harbor, dried, and then shaken for its bioluminescent protein. Children were paid a penny each to scoop up the jellies for use in medical research, and 100,000 were harvested per year. Synthetic manufacture of the protein has eliminated the market.
Jellyfish are also eaten in some Asian restaurants. Mills has tried it, and doesn't recommend the dish. "It's pretty tasteless."
Other common Washington jellyfish include the clear Aurelia, or moon jelly; the large and fringed Cyanea, or lion's mane, which stings; and the red- or yellow-bellied Phacellophora, or fried egg, which is quite common in southern Puget Sound.
Some of the state's most common jellyfish today are believed to be recent invaders, brought here in ship ballast water.
Jellyfish are fussy eaters. Some species prey almost exclusively on other jellyfish, and so ferocious is this jelly-eat-jelly that one researcher has drawn up a food web he calls a "jelly web." Others eat barnacle and clam larvae, copapods, the eggs of other marine invertebrates, other animal plankton, and so on.
Their ecological importance is unclear. In Chesapeake Bay, there has been an explosion of stinging jellyfish after oysters were overharvested. The theory is that with oysters eating less plankton, jellies are dining on the surplus.
In San Francisco Bay, an invasion of a new fingernail-sized clam has wiped out the plankton bloom and jellyfish have declined as a result.
There has been a tenfold increase in jellyfish in the Bering Sea the past decade, an indication of overfishing. "As fisheries get disturbed," Mills explained, "we're ending up with more jellyfish in some places" as the ecosystem is upset.
Some jellyfish sit on the bottom most of the time, drifting upward only at night. Others feed on the surface. Some have chambers that keep them afloat while others will slowly sink if they don't swim. Some flip upside down to feed. One jellyfish the size of a quarter has tentacles 6 feet long.
They have adapted to almost every temperature and every depth. Because the ocean is deep as well as broad - it contains 97 percent of our planet's living space - jellyfish may be one of the planet's most common animals.
IT IS FASCINATING that adult jellyfish, which live for only weeks or months, still seem so leisurely as they drift and dream. Their species have the equanimity of long-term survivors.
How frantic we Northwesterners are by comparison! All our nets, boats, studies and speculations are but a blink of time to the jellyfish, which has survived crashing comets, mass extinctions, global warming, ice ages and the drift of continents. As long as the oceans persist, so will it.
The jellyfish is the ultimate tortoise to our hare, with a silent languor that is a message in itself:
"We've seen it all. Pause, and admire our grace."
William Dietrich, author and former Seattle Times reporter, writes Our Northwest for Pacific Northwest magazine. ------------------------------- Lifecycle of a jellyfish
Jellyfish have an odd life cycle in which the animals spend part of their time looking like plants. The cycle begins in summer or fall, when adult jellyfish release eggs and sperm into the water. A fertilized egg develops into a larva that briefly swims and feeds, then settles to a hard surface, anchoring itself and becoming a stalk-like polyp. The polyp lives through the water, feeding like its cousin the sea anemone, and with the return of the sun it buds tiny jellyfish. These grow to adults in a single season before the cycle begins again.
Copyright (c) 1999 Seattle Times Company, All Rights Reserved.