Author: Elizabeth Devitt / Source: Science News for Students
Sharks aren’t the scariest things in the ocean for scientists who dive to work.
Powerful currents, created where the ocean floor drops away, can be just as deadly.“You can get sucked down and crushed by the pressure within minutes,” notes Marcel Jaspars. He’s a chemist who once saved himself from such a current. He encountered it while taking photos of a sea sponge near Indonesia, in Southeast Asia. Luckily, he inflated his dive vest in time. He was able to float to the surface and escape the potentially deadly current.
Diving has risks. But the scientists who work underwater train to deal with these dangers. For Jaspars, the rewards of research and underwater adventure are greater than the risks. He searches for unusual chemicals made by ocean life. Then he analyzes them for ingredients that might serve as medicines for people.
The sea may seem like a strange place to look for new drugs. But organisms in the ocean have had to adapt to a tough environment. Some of the chemicals they make for survival might help people, too. More than 50 years ago, scientists discovered a new anti-cancer drug in a sea sponge. Since then, researchers have been hunting the seas for more of such useful natural products.
With the help of underwater robots and small submarines, Jaspars and other scientists are searching the seas — from shallow reefs to the oceans’ great depths. Their goal: finding chemicals made by marine life for use in one day treating human disease.
Jaspars’ research has taken him from the bright blue waters around Indonesia to the Red Sea (south of Israel, and bordering many African nations). He got hooked on diving after watching television shows about ocean explorer Jacques Cousteau. By the time Jaspars was 16, he had earned his certification to dive in the cold waters off Great Britain. Later, he studied chemistry and biology. Those studies now help him figure out how to turn marine molecules into human medicines.
Consider sea squirts. These soft, boneless animals anchor their bodies to the sea floor. As they pump food-laden water through their bodies, they filter out any bits they can eat. Certain squirts on Australia’s Great Barrier Reef also make chemicals that can kill human cancer cells. (The chemicals probably help the squirts defend themselves.) Jaspars helped figure out how to get bacteria in a lab to produce the same chemical. This let scientists study the chemical without collecting — or harming — any wild sea squirts.
Now Jaspars directs the Marine Biodiscovery Centre. It’s at the University of Aberdeen, in Scotland. There he focuses on microbes living in very cold environments, such as the Arctic Ocean. “It’s too cold and deep to dive there,” he says. So scientists on research ships haul up buckets of sludge from the seafloor. Later, they send him small samples of what they’ve hauled up.
Microbes living in the Arctic’s frigid waters break down their food using different tactics than do organisms on land. This process of turning food into energy for growth, activities and reproduction is called metabolism (Muh-TAA-buh-lizm). These pathways also produce chemicals called “secondary metabolites.” Those are chemicals the microbes don’t need to survive. Still, they may be useful to the microbes. One day they also might help people.
During a four-year project called PharmaSeas, scientists made thousands of extracts from those seafloor samples. Working with researchers from across Europe, Jaspars whittled that number down to about 700 “extracts of interest.” In about a dozen of them, researchers found compounds that can kill bacteria that some of today’s antibiotics cannot. Three other newfound chemicals reduce epileptic seizures (electrical storms in the brain) in mice. Yet another compound may reduce the symptoms of Alzheimer’s disease. That chemical came from a previously collected sea sponge from the Philippines.
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Soon Jaspars will start the same process with new batches of mud from Antarctica. These samples were dredged up as deep as 5,000 meters (3.1 miles). The pressure at that depth is far greater than at sea level. With a new lab instrument, Jaspars will be able to simulate that pressure. That will help the microbes from the seafloor feel like they’re at home. Researchers need to recreate such harsh conditions to nurture organisms that are used to extreme habitats. And, Jaspars suspects, such organisms will likely make metabolites no one has ever seen before.
Unlike Jaspars, Shirley Pomponi never dreamed of becoming a deep-sea diver. She planned to be a nurse. But after her first dive, she knew there was no way she was going to spend the whole rest of her life on land.
“The freedom was amazing,” Pomponi says, recalling her early dives in the Caribbean Sea. “You’re breathing underwater — almost weightless — and looking at all these amazing things.”
Sponges fascinated her the…
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