Scientists Unearth an Ancient Lost Forest ‘Entombed’ Off Alabama's Coast

These underwater cypress trees are 60,000 years old, and may help pioneer new drug treatments.
April 6, 2020, 12:00pm
Logs from the cypress forest. Image: Brian Helmuth (left), Francis Choi (right)​
Logs from the cypress forest. Image: Brian Helmuth (left), Francis Choi (right)

The scene is like something out of a dreamscape: schools of fish swimming through a forest of gnarled, thick-trunked cypress trees that were seeded some 60,000 years ago. But this surreal underwater woodland is a very real place off the coast of Alabama, and scientists think its preserved trees may contain secrets about fighting infections and other ailments.

This cypress forest thrived on land at around the same time that prehistoric humans began migrating out of Africa. As individual trees died and fell to the forest floor, some of them became “entombed” in peat and sediment, according to NOAA. When the Ice Age ended, sea levels rose and these woody time capsules were engulfed by the ocean and buried again, this time under the seabed.

The ancient forest was finally exhumed from its seafloor grave by Hurricane Ivan, which hit the Gulf Coast in 2004 and exposed an arboreal seascape that now lies sixty feet underwater. The precise location of the unique forest has remained a guarded secret, for the most part, though scientists and filmmakers have paid it a few visits.

However, this one site may be “the tip of the iceberg” that hints at a far more expansive preservation of ancient underwater forests, according to Margo Haygood, a molecular biologist at the University of Utah.

“There could be much more underneath [this site] and there could also be other forests in other parts of the Gulf,” Haygood said in a call. “People stumbled upon this one site but there’s likely to be more of them and they could be looked for systematically.”

Haygood is part of an interdisciplinary team that is searching for useful biotechnologies and medical applications within the microbes of this underwater forest ecosystem. In December, the researchers embarked on an expedition to the forest on the research vessel E.O. Wilson, funded by NOAA’s Office of Ocean Exploration and Research.

NOAA released new footage of the underwater area earlier this week and the team expects to publish its first results from the trip within the next few months.

Just like their counterparts on land, these dead logs support a diversity of lifeforms that scientists are now beginning to collect and examine in the laboratory. “We picked apart the wood more or less splinter by splinter and found all kinds of creatures in those samples,” Haygood said, “but there will certainly be more beyond what we have discovered.”

Marine organisms are gaining a reputation as an exciting source of novel pharmaceuticals and clinical treatments, and these underwater cypress trees are packed with varieties that have never been studied before. The December expedition recovered 300 animals from trunks hauled up out of the forest, according to NOAA, and identified about 100 bacteria strains in cultures from the forests, some of which are new to science.

The most useful microbes for medical and pharmaceutical research tend to live symbiotically with host organisms, as opposed to bacteria that survive without an animal host.

“If you focus on the microbes that live in stable, benign associations with other organisms and you look at the chemicals that they produce, they have been preselected by hundreds of millions of years of evolution together to be potent, effective, and non-toxic,” Haygood explained. “They don’t make things that are poisonous to their hosts, they make things that may be useful to their hosts.”

Microbes that live inside of shipworms, a type of mollusk that feeds on ships, piers, and driftwood, are a particular fascination for Haygood and her colleagues. These woodeaters have evolved an ingenious digestive process that helps them break down the tough cellulose material that makes up trees.

The finer details of this animal’s digestive wonders remain mysterious, but scientists do know that shipworm gills contain bacteria that produce enzymes that can break down wood into sugars. These enzymes somehow travel into the shipworm gut, an unusually semi-sterile organ filled with wood chips that the animal has consumed, and transform the sawdust into sugar.

“They’ve sequestered the bacteria, or kept them away from the wood particles, so that they won’t steal all the good stuff, but they’re getting them to make the enzymes that let the host break down the wood and get all of the best food,” Haygood said. “In return for that, they are somehow feeding the bacteria that are in the gill—obviously the bacteria are surviving well there—but they are not letting them have as much as they want, only as much as the host wants.”

The whole process is extremely unique, which prompted scientists to study it more closely. The results revealed that shipworms are “stuffed full of biosynthetic pathways” that are conducive to drug development, Haygood said.

“We were just blown away; we were floored by it,” she added. “We thought these were just garden-variety nutritional symbionts and they wouldn’t have any great talents in terms of biosynthesis.”

Shipworm bacteria has already been used to develop at least one antibiotic, and scientists are hopeful that the tiny creatures living in this ancient forest can yield more.

“The thing about the shipworm bacteria is that they are a whole new universe because they don’t overlap with what’s already been discovered,” Haygood noted. “They are like a treasure chest that hasn’t been opened yet so we’re trying to get the word out that these are a really good group of bacteria to be working on.”

This forest, which flourished at a time when humans were just beginning to emerge as a globally dominant species, may ultimately become a source of life-saving treatments for their descendents.