Ancient Subsurface Waters May Reveal Secrets of Unique Ecosystems

Deep beneath the Earth’s surface, life exists in ways we are just starting to discover. Most of this life is made up of tiny organisms, called microbes, and they may have just as much genetic diversity as life above ground.

Some strange ecosystems likely live with ancient water trapped deep inside rocks. These rocks, called Precambrian shield rocks, are some of the oldest on Earth. A study from 2014 found hydrogen-rich water in 19 mines in Canada, South Africa, and Finland. One mine near Timmins in Canada had liquid water that was isolated for up to 2.64 billion years.

This ancient water can support life because chemical reactions in the rocks produce hydrogen. Two main processes help create hydrogen: radiolytic decomposition, which splits water molecules due to natural radiation, and serpentinization, where certain minerals change and release hydrogen.

Since Precambrian rocks form over 70 percent of Earth’s crust, such places may be more common than we think. Geochemist Barbara Sherwood Lollar described them as a “sleeping giant,” suggesting a large area could support life.

The study of these environments could also offer clues about life on other planets, like Mars, where similar processes could be happening. Earth’s interior might even hold three times the amount of water found in our oceans, but it is trapped within minerals, not as liquid, ice, or vapour.

How much do you know?

What are the tiny organisms that make up most of the life beneath the Earth's surface?

Plants

Animals

Microbes

Fungi

What type of rocks are known as the Precambrian shield rocks?

Igneous rocks

Sedimentary rocks

Metamorphic rocks

Some of the oldest rocks on Earth

How many mines in Canada, South Africa, and Finland were found to have hydrogen-rich water in the 2014 study?

5

10

19

25

How old was the isolated liquid water found near Timmins in Canada?

1 billion years

2.64 billion years

500 million years

3 billion years

What process involves the splitting of water molecules due to natural radiation?

Serpentinization

Radiolytic decomposition

Hydrogenation

Photosynthesis

What phrase did geochemist Barbara Sherwood Lollar use to describe Precambrian rocks?

Sleeping giant

Frozen wilderness

Hidden treasure

Ancient guardians

Most life beneath the Earth's surface is made up of large animals.

True False

Precambrian rocks cover over 70 percent of Earth's crust.

True False

The ancient water found underground can support life.

True False

Earth’s interior holds less water than found in our oceans.

True False

The processes of radiolytic decomposition and serpentinization are responsible for creating oxygen.

True False

The study of life beneath the Earth's surface has no relevance to understanding life on other planets.

True False

Most of the life beneath the Earth's surface is made up of tiny organisms called

The ancient water in the rocks can support life because it produces .

The ancient water in one mine near Timmins had been isolated for up to billion years.

Precambrian rocks are some of the rocks on Earth.

Geochemist Barbara Sherwood Lollar referred to Precambrian rocks as a giant.

Earth's interior might hold times the amount of water found in our oceans.

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