A cross section of Rogenstein oolitic limestone reveals the ooids scientists believe were created by mineralized microbes. Photo by ANU
Jan. 19 (UPI) -- The Pentagon is bugged -- new research out of Australia suggests the stone used to build the Pentagon is home to 340-million-year-old mineralized microbes.
The Pentagon isn't alone. The ancient microorganisms are found in oolitic limestone, a popular construction material found in buildings all over the world, including the Empire State Building. Oolitic limestone is named for its layers of bead-like spheres of calcium known as ooids.
Previously, scientists thought ooids were formed as grains rolled along the ocean floor, collecting sediment as they traveled. Scientists at Australia National University believe microbes account for the ooids.
"We have proposed a radically different explanation for the origin of ooids that explains their definitive features," Bob Burne, a scientist with the ANU Research School of Earth Sciences, said in a news release. "Our research has highlighted yet another vital role that microbes play on Earth and in our lives."
Oolitic limestone has formed all over the world throughout geologic history. The stone has been used as a building material since ancient times.
"Many oolitic limestones form excellent building stones, because they are strong and lightweight," Burne said. "Jurassic oolite in England has been used to construct Buckingham Palace and much of the City of Bath, the British Museum and St Paul's Cathedral."
Scientists used mathematical models to identify the most likely cause of ooid growth. The models utilized algorithms designed to describe brain tumor growth, with the simulations showing the mineralization of microbial biofilms best explains the pattern and size of ooids.
Researchers published their findings this month in the journal Scientific Reports.