50,000 year old cypress forest under the sea

An intact ice age forest found off the coast of Alabama, US, reveals a prehistoric landscape of Earth.

The underwater cypress forest dates back to the ice age more than 50,000 years ago when sea levels were 400 feet lower than today, according to the documentary "The Underwater Forest" by environmental reporter and filmmaker Ben Raines. The forest is located on the seabed off the coast of Gulf Shores, Alabama, in the Gulf of Mexico, Live Science reported on July 19.

Raines learned about the forest from Chas Broughton, a local dive shop owner. Broughton first discovered it a few years ago, 12 miles offshore from Mobile, Alabama, about 60 feet below the surface. When he dove down to get a closer look, Broughton saw massive tree trunks rising from an ancient riverbed that had carved its way into the ocean floor. Like a coral reef, the tree trunks became home to thousands of different species of marine life.

The tree trunk still oozes sap when cut. (Photo: YouTube).

Raines teamed up with paleoclimatologist Kristine DeLong of Louisiana State University to study the forest and try to preserve this natural wonder. The first scientific expedition to the area took place in 2012. Since then, DeLong and his colleagues have continued to uncover the secrets of the forest. The unique conditions have kept the forest in perfect condition. It is believed to be the world’s only preserved coastal ice age forest, hidden deep under the ocean.

Cypress trees typically decompose after about 10,000 years. But in this area, the cypresses survive many times longer because the sediment is made up of mud and sand with low oxygen levels, which inhibits bacteria from decomposing the wood, DeLong explains. The ancient giant cypress forest is so fresh that many of the trunks still ooze sap when cut. Much of the trunks are covered with sea anemones and schools of fish. The most recent trees grew 50,000 years ago, making it the world’s oldest underwater forest.

While analyzing the site, tree-ring dating experts, geologists and paleontologists from DeLong's team gathered rare information about ice age climate, rainfall, insects and plants, contributing to a new perspective on Earth before human settlement.

The team quickly identified the specimens as freshwater marsh cypresses, which had many knots that helped them stand in the mud, similar to those found along the Gulf Coast today. They took core samples for analysis by Grant Harley, a tree ring expert at the University of Southern Mississippi. All the growth rings, resin, and wood fibers were still clearly visible on the stump. “When you run a saw through the specimen, you can smell the resin, like you’re cutting fresh wood today,” Harley said.

Scientists initially thought the forest was about 10,000 years old based on the depth of the area, but carbon dating of surrounding sediments indicated the forest dates from an ice age more than 50,000 years ago.

Under a microscope, growth rings on modern bald cypress trees are thinner, indicating greater environmental stress. Today’s trees, which have more stable growing conditions, tend to have thicker, more regular rings.

The tree-ring data revealed that all the cypress trees in the forest grew and died over a 500-year period, with multiple periods of stress. They died at the same time. The team also tried to analyze pollen from sediments near the trees and found that the environment changed quite abruptly.

At its peak, the river delta was made up of grasslands, which later gave way to cypress forests. As sea levels rose, the grasslands moved inland. The waterside grass slopes retreated inland before rising sea levels swallowed the entire forest.

The team is still learning more about the ancient climate of this ice age. But like everything in the ocean, the submerged forest’s time is running out. If storms and tides continue to expose the forest, it will eventually be eaten away by barnacles and bacteria, Raines said.

Researchers are working with federal agencies like the Bureau of Ocean Energy Management and the National Oceanic and Atmospheric Administration (NOAA) to turn the area into a marine sanctuary.

According to Khoahoc.tv