As shown above: After 437 years on the ocean floor, about half of mary Rose's ships are on display in Portsmouth, England.
Powerful X-rays reveal what was going haywire in devouring the wreckage of King Henry VIII's favorite warship, the Mary Rose. In 1545, after the ship sank in a battle with the French, marine bacteria that produced sulfur gnawed at the wood of the shipwreck for centuries to come. Researchers recently discovered that these residues turned into acidic substances when exposed to the air, causing damage to historical shipwrecks.
The wreckage of the Mary Rose, which sank to the bottom of the English Channel, was not salvaged until 1982. Although caretakers took steps to treat and protect water-soaked buildings, little was known about the types of bacteria that inhabited the wood and whether their by-products would endanger the preservation of rescued vessels.
By comparing X-rays with a technique of atoms in the ship's wood, the scientists found acidic nanoparticles produced by destructive bacteria. Identifying and locating acid-forming compounds that may corrode the hull will help administrators protect this one-of-a-kind craft.
Serena Cussen, chair of the Department of Materials Science and Engineering at the University of Sheffield in the UK, said the new approach "allows us to not only image and locate the nanoparticles in mary rose's wood, but also assess their structure." ”
"This is the first time zinc sulfide nanostructures, a byproduct of bacteria, have not been able to obtain such detailed potentially harmful bacterial species," Serena said. ”
When King Henry VIII ordered the construction of the Mary Rose in 1510, he was only 19 years old at the time and had ascended the throne a year earlier. According to the commissioning party of the Mary Rose in Portsmouth, England, the Mary Rose was a state-of-the-art battleship at that time, carrying up to 8 large guns and weighing about 544 tons. The Mary Rose fought france twice, then capsized unexplained in a battle with the French fleet and sank to the bottom of the sea with about 500 crew members.
As shown above: The battleship Mary Rose served in Henry VIII's fleet for 34 years until it sank at the Battle of Solent in July 1545. This illustration is from a 16th-century manuscript from the collection of the Peppis Library at Modlin College, Cambridge.
In 1971, divers discovered the Mary Rose in the Strait of Solent, located between Great Britain and the Isle of Wight (an island in the English Channel, a county in England). Over the next 10 years, more than 500 divers and researchers helped excavate the ship, removing artifacts one at a time. Then, in 1982, a panel of experts salvaged the hull, about half of which remains intact. Scientists write in a new study that the wood has been treated with polyethylene glycol (PEG), a compound that stabilizes water-saturated wood and prevents it from shrinking when it dries.
However, even after treatment, water-soaked wood can still easily spoil. According to the study, large amounts of sulfur-producing bacteria still lurk in the wood, and over time, PEG breaks down, and it also produces harmful acids.
The relevant report revealed that there may be several tons of sulfur-containing species and PEG decomposition products in the hull of the "Mary Rose", highlighting the seriousness of the problem.
As the image above shows: Although experts have preserved the wreckage of the Mary Rose after it was salvaged from the seabed in 1982, the bacterial species and residual compounds in the wood may have contributed to its further deterioration.
They sampled a 5-centimeter-long wooden core from the hull of the Mary Rose, cut the sample into smaller pieces, and analyzed it with X-rays and scanning electron microscopy (SEM). When scientists compare scattering patterns in the data based on the atomic structure of compounds in wood, they were able to detect nanostructures based on iron sulfide, which are produced by bacteria and, when they interact with oxygen, can form harmful acids.
Serena said: "Our findings alert conservationists to these previously unknown sediments and expand the study of substances that induce degradation. Understanding the structure of these potentially harmful substances also allows us to design targeted treatments to eliminate them in the future. ”