Microbes: Source of Huge Iron-Ore Deposits

The next time you see a red-clay hillside of iron ore, think, tiny microbes might have created the components of that billions of years ago.

That is, University of British Columbia and University of Namur (Belgium) researchers recently published findings in Scientific Reports regarding an isolated bay in a large lake in East Africa where 30 percent of the microbes mature by a means of photosynthesis that rusts iron instead of converting water into oxygen in the way used by algae and plants. The team's work there provided information supporting theories that microbes made ore deposits eons ago, according to their report.

"Kabuno Bay is a time machine back to the Earth's early history when iron-rich ocean chemistry prevailed," said Marc Llirós of University of Namur, in a release.

Also, "The bay is giving us real-world insight into how ancient varieties of photosynthesis may have supported Earth's early life prior to the evolution of the oxygen producing photosynthesis that supports life today," said UBC geomicrobiologist Sean Crowe, in the release.

Although certain bacteria were discovered in 1993 to have photosynthesized iron, the new report shows that microorganisms were likely involved in creating the deposits of Earth's oldest formations of iron, according to the release.

Little oxygen existed in the atmosphere prior to 2.3 billion years ago. There was, however, much dissolved iron. Quite a few organisms, like bacteria, gained energy by processing the metal. An existing theory is that probably microbes changed dissolved iron into minerals--and then those deposited along the ocean floor, as the release noted.

The researchers who went to Kabuna Bay in the Democratic Republic of the Congo, East Africa, found that the microbes there process iron and grow at a successful enough rate that their prehistoric predecessors probably deposited sedimentary iron ore. The latter are called banded iron formations, according to the release.

The microbe role set the foundation of the Earth's chemistry, eventually leading to more complex evolutionary life, such as plants and animals, the release said.