To see Art DeVries at work is to see a burly, ruddy-cheeked, 57-year-old country boy with a ragged, graying, walrus mustache joyfully in his element.
Several weeks every year, DeVries, a native of rural Montana, spends many hours on the ice in remote shacks dropping fish lines down holes into unbearably frigid waters. Happily and often he reels in fish and drops them into a bucket of water.
This, however, isn’t a sport to DeVries. He is a world-renowned University of Illinois biologist who for 35 years has been going to Antarctica to catch and study fish.
What he has found has fascinated scientists from far-flung disciplines who now also study his fish. They see within the silvery perch-like fish potential solutions to problems ranging from safely storing human organs for transplantation to lengthening agricultural growing seasons and even increasing the freezer life of ice cream.
But seeing DeVries at work collecting specimens, such lofty purpose hardly seems possible.
His bait usually is translucent green plastic worms with gold glitter specks embedded in them. The 2-foot plastic rods and reels he uses are stickered with logos of the “Peanuts” cartoon strip dog, Snoopy.
“Kmart and Wal-Mart are full of these things,” DeVries says of his Snoopy gear. “I like them because they’re short, so they’re easy to use inside the shacks . . . and they’re so cheap it doesn’t much matter if something happens to them.”
While his choice of fishing gear might seem odd, the mush-boned fish he catches are truly strange.
Ranging in size from a couple of ounces to 200 pounds, they swim in 28.5-degree salt water that is cooled and fed by 80 percent of the world’s ice.
By normal principles of biology and ice crystallization, Antarctic fish should not be able to survive.
The fish constantly absorb microscopic ice crystals from the supercooled (below freezing but still liquid) water in which they swim.
The crystals are like deadly catalytic seeds in the fish’s blood and tissue. Normally, in such cold conditions, the crystals should grow instantaneously if the fish bumps against a chunk of the plentiful ice that floats in their waters, freezing the fish solidly dead in the blink of an eye.
They avoid that fate by manufacturing antifreeze in their livers that is 300 times more effective than auto antifreeze. Their livers secrete the antifreeze into their bloodstream, flooding the rest of their bodily tissues with its protection.
The antifreeze the fish manufacture has sparked worldwide interest.
Researchers in cryopreservation, for example, are looking at it to see if the fish antifreeze can be used to preserve human organs, storing them for future transplantation. As it is now, organs can only be kept alive for transplant purposes for about 48 hours.
Scientists are inserting the antifreeze into cash crops, such as Idaho russet potatoes, to protect them from frost and freeze. In effect, this would lengthen growing seasons.
The antifreeze is being studied, too, as an additive to ice cream to keep it from crystallizing during a long stay in the freezer. It has even been looked at as a possible de-icing agent for aircraft wings.
DeVries has spent 35 years trying to tease out the mystery of the antifreeze and how it works in the fish. His most recent findings suggest a connection between the antifreeze and the fish’s immune systems.
Deciphering simple, basic immune systems such as those in DeVries’ Antarctic fish would be invaluable to scientists looking for weapons to battle diseases from gallstones to cancer to AIDS.
Cryopreservation, ice cream preservation and unlocking immune systems are all, however, only potential, still unproven benefits of DeVries’ work.
These fish are keepers
But his discovery of the fish with antifreeze has become a landmark in the annals of biology, even if no practical applications ever arise from the antifreeze.
“I think (DeVries’ discovery) is the most interesting known example of adaptation physiology,” says Joe Eastman, an Ohio University physiologist and expert in cold water fish evolution who has followed DeVries to Antarctica.
“It (DeVries’ work) has been a unique evolutionary experiment in a natural evolutionary laboratory. They (Antarctic fish) are like Darwin’s finches on the Galapagos Islands, an example of an animal able to evolve in isolation, changing physiologically as it fills almost every possible niche in its environment.”
When DeVries first arrived in Antarctica as a graduate biology student in 1961, he went to study life in perhaps the most isolated environment on Earth.
No one even knew how many species made up the predominant fish in the ocean, called notothenioids. Bony and perch-like, they claim virtually every fish niche in the vast Antarctic Ocean to themselves.
Until 30 million years or so ago, when Antarctica was a relatively warm and temperate continent, an ancestral species of notothenioids shared its waters with the rich diversity of temperate-water fishes.
About then, however, Antarctica fell into a deep freeze, and temperate-water fishes disappeared.
A curtain of cold descended where the Antarctic Ocean converges with the warmer Atlantic, Pacific and Indian Oceans, barring entry of marine life needing warmer water in which to live.
Only the notothenioids were able to survive and, eventually, thrive in the cold.
DeVries has concentrated much of his effort on two of the most important adaptions made by the fish to survive in an icy environment.
The first is the fish’s ability to manufacture antifreeze. The second is its virtual state of weightlessness in water, a condition known as “neutral buoyancy.”
Unlike most fish, the 20 notothenioid species he has found lack swim bladders. Internal gas-filled bags, swim bladders are used by most fish to maintain themselves at whatever depth they wish.
By becoming neutrally buoyant, Antarctic fish can maintain their depth position without expending energy on flotation.
They became neutrally buoyant by developing ultralightweight scales and bones–skeletons composed of soft bone and a hollow spinal column–and strategically placed fat deposits in their bodies.
The Antarctic fish are to other fish what ultralight aircraft are to conventional aircraft.
“Most fish adjust their position in the water column (the depth between the surface and bottom where they spend most of their lives) with their swim bladder,” says DeVries.
“With this adaptation, Antarctic fish don’t have to expend any energy maintaining their position, because they don’t weigh anything in the water. Even a midwater fish (living at a depth of 900 to 1,200 feet), weighing 100 pounds or more, weighs less than a postage stamp in the water.”
DeVries believes the 20 notothenioid species he sees today came from one ancestral species. New species evolved as offshoots of the ancestor in order to take over ocean habitats left vacant by disappearing warm-water fish.
A lifetime on ice
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DeVries is a sort of “Grand Old Man” of America’s Antarctic science program. Though nobody keeps track of such things, he has probably spent more time on the Antarctic continent than any other American in history.
Since 1961 he has spent two yearlong stints in Antarctica and nearly 30 summer seasons, each typically about two months long. He left last fall for yet another season both at McMurdo and aboard a ship from which he will be collecting fish from the deepest waters of the Antarctic Ocean.
Getting DeVries, his Snoopy gear and graduate assistants down to his fishing shacks and labs at McMurdo, the main U.S. Antarctic base, does not come cheaply, nor does supporting his labs in Urbana. In all, it costs about $130,000 a year in tax-supported National Science Foundation grant money.
When DeVries is in Antarctica, he spends most of his time working in his labs, overseeing an aquarium he maintains there for the lab, and catching fish. Most of his fish shacks are within a half-hour drive in tracked vehicles on the ice from the base.
He also travels to ice over deeper waters, however, sending fish traps down 1,500 feet or more. And he visits waters elsewhere around the huge Antarctic continent (1 1/2 times bigger than the U.S.) to gather specimens.
Like a good detective chasing a baffling case, DeVries continually finds himself in new precincts as he pursues the mystery of the fish with antifreeze.
In 1973 he went to the Arctic region to find out how fish there survive in the frigid waters on the other end of the Earth.
“We’ve found this antifreeze in Arctic cod around Spitsbergen (in the Norwegian Sea); Point Barrow, Alaska; and northern Greenland,” he says.
The most daunting journeys DeVries has made in following the mystery have not been physical ones, but intellectual ones that send him into new scientific arenas.
Immune system mystery
The most notable–and newest–of these journeys began three years ago when one of his students discovered that ice crystals in their Antarctic fish always travel to the spleen and disappear.
They now know this response is linked to the notothenioid immune system. Since this discovery, the main interest of DeVries and his team has been to discover how immune systems, in his fish and other living organisms, fight off invading foreign bodies, be they cold virus, cancer cells or ice crystals.
DeVries now believes the fish immune systems are treating the ice crystals like any other foreign antigen once they are coated by antifreeze cells. By tagging tiny crystals to make them fluorescent, he and his assistants at McMurdo this season hope to follow the process and discover how the crystals are dissolved.
“Though the temperatures inside the spleen are never warm enough to melt the crystals, the crystals disappear,” he says. “We think it is the macrophages dissolving the crystals, but how they do that is a very interesting question we’re now trying to answer.”
The fish immune system is a long way from a human immune system, but it is a good start in understanding how such biologic mechanisms work.
“Understanding this very simple system, we might gain information to apply to more complex situations, such as kidney stones,” DeVries says.
DeVries says it will be at least a year before he and his assistants are ready to publish their findings on fish immune systems.
When they do, it is certain to again focus interest on the Antarctic fish, especially from scientists struggling to find ways to combat viral diseases such as AIDS and cancer.
There is still enough of the country boy in DeVries, however, that AIDS, antigens and antifreeze seem like remote concerns as he huddles over his ice holes in his fish shacks down in Antarctica.
As he happily reels in his catch, it’s easy to forget he is really collecting research specimens.
Indeed, just before he left Urbana for the new summer season in Antarctica in the fall, he seemed nearly as enthusiastic about some new fishing gear he was taking as he was about new research agendas.
“It’s one of those old Popeil Pocket Fisherman deals they used to advertise on TV all the time,” DeVries said. “A friend of mine found it in his stuff and gave it to me.
“It’s just the right size for the shacks. I bet this thing will work just great.”
ENVIRONMENTAL TREASURES
Scientists are studying a group of fish in Antarctica that manufacture their own antifreeze and could yield benefits like safe storage of human organs, longer agricultural growing seasons and even an increase in the freezer life of ice cream. Practical applications aside, these fish are a remarkable study in evolution since they have adapted to some of the harshest conditions on Earth.
NATURE’S MEDICINE CHEST
PROMISING OCEAN DISCOVERIES
Scientists are being drawn to the seas, where less than 1 percent of marine life has been screened for its medical potential. Discoveries made so far, though, already have produced a bounty of elements being used in the pharmaceutical and biomedical industries.
Crabs, lobsters, shrimp
The shells of these popular seafoods are rich in a substance called chitin, used to make sutures, bandages, drug delivery systems, food additives and dietary supplements.
Scallops
Stock left over from scallop processing contains an anti-cancer agent identified as glycogen poly-sugar.
Horseshoe crab
This crab produces proteins used to detect a potentially life-threatening bacteria sometimes found in canned foods and pharmaceutical products.
Coral
Certain species of coral are used in bone grafts to produce newly mended bone that is as strong or stronger than the original.
Shark cartilage
A substance in shark cartilage is being tested for its ability to inhibit blood supply to tumors, thus restricting their growth. It is already popular as a health supplement for some cancer patients.
LABORATORY OF EVOLUTION
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The harsh conditions of the Antarctic are a frigid equivalent to the Galapagos Islands where Charles Darwin formed his theory of evolution. The finches that Darwin observed lived in an isolated habitat and adapted to it by evolving physically. Similarly, the fish that thrive in the Southern Ocean, called notothenioids, have also made remarkable physical adaptations.
– Why the region is isolated
Two conditions keep warm-water fishes away and allow notothenioids to evolve without competition.
– Continental shelf
The shelf along the coast of Antarctica plunges toward the ocean floor at a steep angle, leaving little room for most fish to spawn.
– Antarctic convergence
Swirling and diving ocean currents create this zone that forms a barrier to warm water (and warm-water fish) by keeping the Southern Ocean extremely cold.
– How notothenioids survive in the cold
Notothenioids make up 90 percent of the individual fish in the Antarctic region. Their success stems from their ability to produce antifreeze and conserve energy.
Antifreeze production
Ice crystals would normally enter fish through the gills and expand, freezing the fish’s body fluids. To combat this, notothenioids produce antifreeze molecules (sugars combined with acids) that lower the temperature at which their bodily fluids freeze to 27.
Conservation of energy
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The Antarctic environment lacks light and heat, and it demands that fish conserve their energy. Notothenioids do so by staying lightweight and slowing their metabolism.
Lightweight structure.
– Notothenioids’ skeletons contain cartilage which is lighter than the heavy, bony material found in most fishes’ skeletons.
A notothenioid cross-section.
– Hollow spine. Most bony fish have solid spines that are heavier than the notothenioids’.
– Fat deposits. Strategically placed sacks aid in floatation.
– Muscle fibers.
Weightlessness without a swim bladder
Most fish have swim bladders (internal, gas-filled sacks) to help them stay at a certain depth in the water. However, notothenioids are light enough not to need a swim bladder, which saves the energy spent filling them.
Slowing the metabolism
Notothenioids’ blood has half the hemoglobin (oxygen carriers) of temperate-water fishes. This thins their blood and slows down their bodily processes to save energy.
Notothenioid
Species range from 2 ounces to 200 pounds
The Antarctic habitat
Notothenioids live at various depths in the water under two layers of ice.
Annual ice
Solid up to 9 feet deep, it breaks up in the summer.
Platelet ice
Long, loosely grouped crystals about 4 feet deep. Nearly disappears in summer.
Water
Full of tiny ice crystals, its temperature stays close to 28 degrees.