Undersea Microbes Wake Up After 100 Million Years

South Pacific Gyre —(Map)

Scientists have woken up tiny life forms called microbes that are over 100 million years old. The microbes were found in samples pulled from deep under the sea floor beneath miles of ocean.

As plants and animals die in the ocean, they break down into smaller bits of matter. These bits, along with other dust, wind up slowly settling to the bottom.

The bits that settle on the bottom of the ocean are called sediment. As this sediment falls, tiny microbes, such as bacteria,  get trapped, and wind up packed in the sediment at the ocean’s bottom.

This has been happening for hundreds of millions of years. Different layers of sediment on the sea floor contain information about things that happened at different times in the ancient past.

For decades, scientists have been studying these sedimentary layers to collect information on what the world was like long ago and how it has changed over time.

Since the sediment makes up the sea floor beneath miles of ocean, scientists have to get it by drilling out samples, called “cores”, and pulling them to the surface, where they can be stored and studied in laboratories.

Ten years ago, a team of scientists from Japan and the University of Rhode Island (URI) collected core samples of sediment from the sea floor beneath the South Pacific Gyre – an ocean area with little sea life, and without much food.

The scientists wanted to study whether life could exist in an area with so little food. They were also curious to learn how long microbes could stay alive with almost no food.

The researchers drilled 244 feet (74.5 meters) into the sea floor beneath 3.5 miles (5.7 kilometers) of ocean. They collected a lot of cores.

When they studied the samples, the scientists learned that all of the cores had oxygen in them. That’s important because many microbes need oxygen to survive.

The scientists, led by Yuki Morono, kept the samples in special conditions in a laboratory for over a year and a half (557 days), trying to get them to grow. The team wanted to see if any of the microbes in the samples were still alive. Because of the oxygen, it seemed possible, if unlikely.

Amazingly, around 99% of the microbes became active again. Many different kinds of bacteria began growing and dividing. That’s the basic life cycle for bacteria.

The scientists found the results hard to believe at first, since the creatures are about 101.5 million years old.

Based on the oxygen they found in the cores, and the rate at which sediment falls, the scientists believe that there could be oxygen, and living microbes, all the way through all of the layers of sediment down to the rock bottom.

Now that the team knows how to get ancient bacteria to grow again, they want to explore further to learn more about life from the ancient past. They say that since changes in life forms happen much more slowly down deep, there is much to learn from the way these ancient microbes developed.