The animals likely built the reef to protect themselves from threats in their environment

Jun 27, 2014 09:03 GMT  ·  By
Researchers announce the discovery of 550-million-year-old reef in present-day Namibia
   Researchers announce the discovery of 550-million-year-old reef in present-day Namibia

A paper published this June 26 announces the discovery of one of the world's oldest reefs in present-day Namibia. Unlike other ancient reefs that came into being due to erosion and sediment deposition, this one was created by animals.

Writing in the journal Science, specialist Rachel Wood with the University of Edinburgh in Scotland and fellow researchers detail that this recently discovered reef in Namibia is nearly 550 million years old.

More precisely, the reef is estimated to have been created about 548 million years ago. According to Rachel Wood and her colleagues, this makes it the oldest animal-built reef to have until now been discovered anywhere in the world.

Evidence uncovered by specialists indicates that it was built by ancient creatures dubbed Cloudina. These creatures were similar to modern-day corals and are believed to be the world's first hard-shelled animals.

By the looks of it, Cloudina were pencil-shaped creatures. The average specimen is believed to have measured about 5.9 inches (15 centimeters) in length and roughly 0.3 inches (approximately 8 millimeters) in diameter.

Specialists have reasons to believe that these animals built the 550-million-year-old reef looking to protect themselves against threats in their environment. One other possibility is that the reef helped them soak up nutrients.

As detailed in the journal Science, evidence at hand suggests that, in order to erect this reef, Cloudina produced calcium carbonate-based natural cement that it used to attach themselves not only to surfaces in their proximity, but also to each other. In time, they formed rigid structures.

The fact that these ancient creatures had to resort to these rather extreme measures to keep themselves safe from potential threats and ensure that food availability was not an issue indicates that, during the Earth's Ediacaran Period, life was rather tough.

“Modern reefs are major centers of biodiversity with sophisticated ecosystems. Animals like corals build reefs to defend against predators and competitors,” specialist Rachel Wood explains in a statement, as cited by Phys Org.

“We have found that animals were building reefs even before the evolution of complex animal life, suggesting that there must have been selective pressures in the Precambrian Period that we have yet to understand,” the University of Edinburgh researcher adds.

Until the discovery of this 550-million-year-old reef in present-day Namibia, the world's oldest structures of this kind were considered to be reefs built by creatures during the Cambrian Period, i.e. about 530 million years ago, when biodiversity really took off.