[Science] Crusty Greek Statue May Aid 'Biofouling' Fight
August 7, 2009—This Greek athlete may look a little green around the gills. But considering that he's been underwater for 2,000 years, he's in remarkable shape. The pictures above show the head of an ancient Greek statue—discovered off the coast of Croatia in 1998 (see map)—before (right) and after its coating of animal-made minerals was removed.
The head had detached from the rest of the bronze figure, which is thought to have been cast in Greece in the first century B.C. The full statue is an example of a common pose in ancient Greek art: an athlete scraping dust and sweat from his body with a small, curved tool.
The front of the 6.2-foot-tall (1.9-meter-tall) statue was found encrusted with 1.2 to 1.9 inches (3 to 5 centimeters) of biomineralizing organisms, creatures such as tubeworms, clams, and barnacles that form their own hard shells.
Underneath the biological crust, the corroded metal had taken on otherworldly hues.
"The color is related to the formation of green copper oxides on the statue, while the red coloration of the lips is due to a pure tin metal inlay in the bronze," said Davorin Medakovic, of the Rudjer Boskovic Institute in Zagreb.
Croatian scientists restoring the statue say the once crusty athlete can offer clues to how marine organisms absorb metals to form minerals for their shells. (Related pictures: "Underwater Museum for Egypt Sunken Treasures?")
Even creatures not in direct contact with the figure's surface took up some of its metals, Medakovic's team noted in their study, published in May in the online version of the journal Crystal Growth & Design.
What's more, the study "has shown the huge impact and disruption that this metal uptake had on the organisms' metabolic pathways, and that caused the distressed organisms to produce untypical minerals" in their shells, Medakovic said.
Living on a steady diet of copper and tin, the organisms on the statue had "digested" the metals to produce shells with unusual ratios of magnesium calcite and aragonite, for example, as well as traces of feldspar and quartz.
Knowing which metals mess up the creatures' digestion, Medakovic said, could help researchers develop metals that are more resistant to "biofouling," the accumulation of barnacles and other critters that can eat away at ships' hulls.
Source: http://news.nationalgeographic.com/n...a-picture.html
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