DAUPHIN ISLAND, Ala. – It was 6 a.m. at the dock in December, and the weather did not look promising. Fog hovered over the water, and the engine of the Research Vessel E.O. Wilson rumbled.
But by 7:30 the crew, a team of biologists, chemists and microbiologists, reached its destination: a secret world where land and sea swap places, and past, present and future collide.
This is the underwater forest. Its unusual residents, shipworms and related marine organisms, could serve as incubators of unexpected medicines, churning out new lifesaving formulas and compounds that may not be found anywhere else on the planet. But first the group of scientists had to manage to dive 60 feet beneath the ocean’s surface to recover their unusual subjects.
“Underwater forest” is not a metaphor — this is a not a coral reef or a sea grass bed that resembles surface woodlands but bona fide trees with roots and leaves. For thousands of years, this cypress grove — about two football fields long and 5 feet wide — lay silent, preserved within an oxygen-less tomb of sand and sediment. Then came Ivan.
In 2004, the hurricane ripped through the Gulf of Mexico, kicking up 90-foot waves. It scooped up nearly 10 feet of sand from the seabed, awakening the forest beneath.
Few have seen it, and those who have keep its location secret. But they entrusted this group of scientists, led by Dan Distel, a shipworm marine biologist and director of the Ocean Genome Legacy Center at Northeastern University, with the highly guarded coordinates.
With a grant from the National Oceanographic and Atmospheric Administration, this group aboard the E.O. Wilson was the first to explore, document and study the shipworms and other marine xylophiles that moved into the forest when it emerged.
Shipworms, the scientists say, are critical for drug discovery. As aging populations increase and antibiotic resistance threatens public health, the medical field is seeking a new frontier that might yield novel drugs to treat conditions such as cancer and chronic pain, and to stem deadly infections. So they’re turning to these aquatic wood-lovers and their symbiotic bacteria, which are great chemists.
The forest was once a swamp about 100 miles inland. Its bald cypress trees, and their buttressed trunks as big as cars, supported a diversity of terrestrial life. Now it shelters grouper, red snapper, mantis shrimp, crabs, anemones and other dwellers. And for shipworms, it’s an all-you-can-eat buffet.
“This is sort of like a wooden whale fall,” Margo Haygood, a molecular biologist, said of when a dead whale that sinks to the seafloor and life erupts around it.
The sunken forest is larger, farther from shore and older than anything remotely like it. And as novel habitats and money for drug discovery dwindle, and with antibiotic resistance, new diseases, infections and age-related illnesses rising, the researchers think it has everything to uncover new drugs.
Like wildflowers after a fire, diversity blooms as new habitats are established. In the early stages of settlement, territory disputes kick up a lot of chemistry. And while sifting through it all, Haygood thinks there’s a better chance for finding nontoxic new drugs.
Shipworms appear to be good drugmakers, and while studying them elsewhere, the team has discovered compounds that are now making their way through the early stages of drug development.
Their pharmaceutical talent might be explained by bacteria living in their gills, which send enzymes to the gut to help shipworms break down wood. Somehow, this process also leaves the gut nearly sterile, suggesting antibiotics might be at play. And Haygood said that any compounds they find have already gone through millions of years of pre-screening in the bodies of shipworms. This makes them likely to be less toxic to humans than drugs that are whipped up in a lab.
Each species, they have found, has a distinct and different set of bacterial partners, or symbionts. In their view, every unstudied species, every specimen, is potentially an unopened treasure chest of unimagined chemical combinations. And a site like the underwater forest might be concealing millions of unknown bacteria.
If the underwater forest is a natural experiment, the rig offers a control. The rig’s towering bases serve much like the eroding underwater stumps or any object tossed into these vacant waters.
The team wanted to see whether deploying wooden blocks along the base in the future might address questions that can’t be asked at the underwater forest: Did the forest attract marine life that was already in the area, similar to what is drawn to a gas rig? Or did it give rise to a unique ecosystem? How long does wood typically last underwater among wood-eaters under different conditions?
The vessel, having reached the rig, idles on foamy water beneath its rigid steel beams. Three divers jumped in and returned a few minutes later with good news: Visibility was perfect, and they captured great footage of the sea life.
The rolling weather signaled that time had run out for further examination. Luckily, during an earlier sea-sickening dive, they still managed to collect six large buckets of logs, branches and roots.
The team gathered around a picnic table beneath a beachy-pink building on stilts at Dauphin Island Sea Lab. A plastic tarp for a tablecloth, lunch trays for workstations. The researchers set out to categorize samples they had gathered. The wood was sorted based on how long each piece was estimated to have been exposed, from briefest to longest, in the hopes of understanding what types of creature settle on which substrate.
The wood was so pliable it could be picked apart with fingers, splinter by splinter. The scraps looked like pulled pork. Haygood welcomed today’s guests of honor with gloves: shipworms, pholadidae and bryozoans, the oddballs that might bring drugs to the table.
Sailors named shipworms, which burrow into and devour wooden ships and dikes. But they are not worms; rather, they are elongated clams that grind into wood with microscopic teeth, and digest the wood with the help of symbiotic bacteria in their cells.
Pholadidae, which resemble white grapes, are shipworms’ younger cousins. Somewhere during their evolution, pholadidae lost the symbiotic bacteria in their cells, along with their ability to consume wood. But shipworm-associated bacteria that potentially contain pharmaceutical gold could hitchhike on their bodies.
Then there are the bryozoans, a phylum of animals all its own. Bryozoans attach to wood but don’t eat it. Some colonies resemble gummy-ish lichens, but are woven squares. Each square, often smaller than the tip of a pin, is an individual animal. Its bacterial symbionts produce chemical defenses that protect the animal’s soft body and larvae. Some of these toxins and other compounds could be helpful in treating Alzheimer’s, cancer, HIV or pain.
As the team picked out specimen after specimen, they carried them to a makeshift lab. They documented and processed as many as possible before returning to their labs in Utah and Massachusetts.
A single specimen can generate dozens of strains of bacteria. Screenings take months. If a compound passes all the tests, presuming funding continues, they might reach the clinic in 15 to 20 years.