What Lies Beneath

Cypress tree in Louisiana  Bayou (author photo)

By Glennis Waterman

Just ten miles off the coast of Alabama some 60 feet below the surface of the Gulf of Mexico, lies a mysterious sunken forest of giant cypress trees. First discovered in 2004, after Hurricane Ivan displaced a ten-foot layer of sediment, the trees were thought to be 10,000 years old. But by using radio carbon dating and other methods, researchers found that the wood was actually more than 50,000 years old – five times older than estimated. The forest dates to an era when sea levels were hundreds of feet lower than today, the earth’s water trapped in glaciers that covered most of North America. The forest, a unique relic of an era before the most recent Ice Age, will provide information not only about North America before human habitation, but also about the effects of climate change. One account calls the find “a prehistoric time capsule of the coastline and its climate.” (Holley)

Buried by mud during an era of rapidly rising sea levels, the trees were protected from decomposition due to lack of oxygen in their watery grave. Because of this, the wood is remarkably preserved. Samples brought to the surface were dried out and analyzed. When cut, the wood smelled of fresh resin, with sap oozing from cut surfaces (Graham).

Dating the forest posed a challenge to scientists, because radio carbon dating goes back only 50,000, and the data at that age is unreliable. So core samples of sediment were used to supplement the data, supporting the estimate that the trees are older than 50,000 years (Alabama Media).

In addition to the trees themselves, sediment core samples surrounding them yielded pollen that showed what happened as the water rose over a period of nearly 500 years.  What was once a coastal forest with stands of cypress, alder and oak, similar to those of modern-day Virginia and the Carolinas, changed to grassland and then marshlands before saltwater incursion killed the trees. Researchers believe that sea levels rose as much as eight feet per hundred years, at a far quicker rate than anticipated today. Beneath the top layer of sand researchers discovered a layer of peat, organic matter from rotting vegetation that typically lies on the bottom of bogs and marshes. (Alabama Media).

It’s important to protect this extraordinary find for future research, so the exact coordinates have not been published, and there are efforts to have the site declared a National Marine Sanctuary (Alabama Media). So, for now, the sunken forest serves as a home for sea anemones, sea sponges, octopus and fish (Ghose). You can experience the forest through the documentary “The Underwater Forest” (Raines).

Sources:

“Alabama's 60,000-year-old underwater forest spills its secrets in new documentary.”  AL.com. Alabama Media Group. 6/25/2017. http://www.al.com/news/mobile/index.ssf/2017/06/underwater_forest_discovered_alabama.html  Accessed 27 February, 2018

Ghose, Tia. “Underwater Cypress Forest from Ice Age Reveals Its Secrets.”  Live Science.  July 19, 2017. https://www.livescience.com/59852-hidden-secrets-underwater-forest-revealed.html  Accessed 25 February, 2018

Graham, Karen. “Alabama's ancient underwater cypress forest giving up its secrets.”  Digital Journal.com July 16, 2017. http://www.digitaljournal.com/tech-and-science/science/alabama-s-ancient-underwater-cypress-forest-giving-up-its-secrets/article/497758#ixzz58RaQQpB9  Accessed 25 February, 2018

Raines, Ben. “The Underwater Forest.” A video produced by Ben Raines and This is Alabama.com. http://www.thisisalabama.org/underwaterforest/  Accessed 24 February, 2018

Holley, Peter. “A mysterious underwater forest warns of Earth’s rapidly changing climate.” Washington Post. June 29. 2017. https://www.washingtonpost.com/news/speaking-of-science/wp/2017/06/29/a-mysterious-underwater-forest-warns-of-earths-rapidly-changing-climate/?utm_term=.5d1d8eb134d0  Accessed 26 February, 2018