Imagine Earth as a beautiful blue, green, and white marble floating in space, full of life. We share this planet with countless animals, plants, fungi, and bacteria. But did you know there’s another hidden world beneath us? Scientists have discovered a fascinating place called the deep biosphere, which lies far below the Earth’s surface.
The deep biosphere, sometimes called the dark biosphere, is a mysterious world without light. For the past ten years, a group of over 1,000 scientists from the Deep Carbon Observatory has been exploring this hidden realm. They’ve been studying life forms found in mines and deep boreholes, some as deep as 5 kilometers below the Earth’s surface and 2.5 kilometers below the seafloor.
The deep biosphere is enormous! Scientists estimate it contains 2 to 2.3 billion cubic kilometers of living organisms. To put that in perspective, it’s almost twice the volume of all the Earth’s oceans combined. Imagine filling a container with all the water from the oceans, doubling it, and then filling it with living organisms—most of which are microscopic.
Not only is the deep biosphere huge, but it’s also incredibly diverse. Scientists compare it to the Galapagos Islands or the Amazon rainforest because of its variety of life. However, instead of mythical creatures, the deep biosphere is mostly home to bacteria and single-celled organisms called archaea. There are millions of different types, many of which we’ve never seen before.
In fact, scientists believe that about 70% of all Earth’s bacteria and archaea live in the deep biosphere. With an estimated 1 trillion species of microbes on Earth, 99.999% of them are still undiscovered. This means that the trillion microbes we haven’t classified yet are just 30% of Earth’s bacteria. The rest are hidden beneath us.
So, why are scientists so interested in this hidden world? The organisms living in the deep biosphere are very different from those on the surface. They survive without sunlight, endure massive pressures, and withstand extreme temperatures. Some even have life cycles that span geological time scales, meaning they grow and reproduce over eras and epochs instead of days or weeks.
These organisms get their energy from unusual sources, like rocks. Studying them helps us understand the limits of life on Earth and how life might exist in extreme environments elsewhere in the universe.
Exploring the deep biosphere raises many questions. Did life start below the surface and move up, or was it the other way around? How does the deep biosphere interact with life on the surface? The more we learn, the more we realize that life can thrive in unexpected ways.
By studying these extreme environments, we might gain insights into what to look for when searching for life on other planets. For example, the organism Geogemma barossii holds the record for living at the hottest temperature, thriving in hydrothermal vents at 121 degrees Celsius.
As we continue to explore the unknown, who knows what incredible discoveries await us? Stay curious and keep exploring the wonders of science!
Using materials like clay, cardboard, and paint, create a 3D model of the deep biosphere. Include layers of the Earth and highlight where the deep biosphere is located. Label different sections and organisms that might be found there. This will help you visualize the scale and depth of this mysterious world beneath our feet.
Choose a microbe that lives in the deep biosphere and research its characteristics. Prepare a short presentation for your class, explaining how this organism survives in such extreme conditions. Include interesting facts about its life cycle and energy sources. This will enhance your understanding of the diversity and adaptability of life forms in the deep biosphere.
Imagine you are a scientist exploring the deep biosphere for the first time. Write a creative story about your journey, the discoveries you make, and the challenges you face. Use scientific facts from the article to make your story realistic. This activity will help you engage with the material in a fun and imaginative way.
Participate in a class debate on the possibility of life existing in extreme environments on other planets, similar to the deep biosphere. Use evidence from the article to support your arguments. This will encourage you to think critically about the implications of the deep biosphere for astrobiology and the search for extraterrestrial life.
Plan an expedition to explore the deep biosphere. Outline the equipment you would need, the types of scientists you would bring, and the research questions you aim to answer. Present your expedition plan to the class. This activity will help you understand the complexities and challenges of scientific exploration in extreme environments.
**Sanitized Transcript:**
The Earth. An inscrutable blue, green, and white marble suspended in the vacuum of space, teeming with life on its surface. You and I, countless animals, plants, fungi, and bacteria inhabit the mountains, plains, rivers, and oceans of our planet. But something is lurking beneath our feet. According to new research, there is a whole other world.
This new world, slowly being revealed to us, is what scientists call the deep biosphere because it lies many meters below the Earth’s surface. It’s also sometimes referred to as the dark biosphere, due to the absence of light in that environment. The Deep Carbon Observatory is a global community of over 1,000 scientists who, for the past ten years, have been exploring this subterranean world and what lives in it.
The latest press release from this research community, as their decade-long project comes to an end, reveals just how startling the deep biosphere really is. The team sampled life forms found at mines and boreholes drilled up to 5 kilometers below the Earth’s surface and up to 2.5 kilometers below the seafloor. With hundreds of samples, they were able to model the size and makeup of the deep biosphere, and it is enormous.
The DCO estimates that the deep biosphere is probably made up of 2 to 2.3 billion cubic kilometers of living organisms, which is almost twice the volume of all of the Earth’s oceans. Just let that sink in: take the entire water volume of the Earth’s oceans, pour it into a container, double that container, and then fill it to the brim with living organisms—most of which are microscopic.
But the size isn’t the only impressive aspect of the deep biosphere. It’s also incredibly diverse, with scientists on the project calling it the subterranean Galapagos or likening it to the Amazon rainforest. However, we’re not talking about mythical monsters; the deep biosphere is mostly made up of bacteria and another type of single-celled organism called archaea—millions of distinct types, most of which we’ve never seen before.
We have no idea what many of these organisms are, but they are so plentiful and distinct that scientists believe about 70% of all of Earth’s bacteria and archaea probably live in the deep biosphere. As of 2016, it is estimated that there are around 1 trillion species of microbes on Earth, and scientists think that 99.999 percent of them have yet to be discovered. According to this new deep biosphere research, that trillion microbes that we haven’t even begun to classify? That’s only 30% of the Earth’s bacteria. The rest are beneath us.
Some scientists even refer to this unclassified life as microbial ‘dark matter’—we know it’s there, but we just don’t know what it is or how it works.
So, besides the fact that this is incredibly fascinating, why are these scientists dedicating ten years of their lives to this research? Why is it important? The organisms that live in the deep biosphere are quite different from those that live above the surface. They must survive without sunlight, withstand massive pressures, and endure extreme temperatures beneath the oceans or kilometers deep inside the Earth.
Some of them have life cycles on geologic time scales, meaning they reproduce and grow over time increments like eras and epochs, rather than minutes or days. They derive their energy from vastly different materials than we’re used to, in some cases subsisting on nothing more than rock.
All of this indicates that the deep biosphere is a world of extremes. With the help of advanced deep ocean and continental drilling technologies, along with the increasing accuracy and availability of DNA sequencing, exploring it will expand our understanding of our own world and its biodiversity.
Investigating the deep unknown may help us answer lingering questions about this environment: Did life start below the surface and migrate up, or was it the other way around? How does the deep biosphere interact with and influence the surface biosphere, if at all?
Perhaps most intriguingly, the Deep Carbon Observatory has shown us that we have not yet discovered the limits for life on our planet. The deeper we dig and the more extreme environments we explore, life continues to flourish in unexpected ways. If life here can be so different from what we have imagined, what might be waiting for us on other planets?
By familiarizing ourselves with the organisms of extremes here on Earth, we may gain insights into what to look for when searching for life elsewhere.
Fun fact: the naturally occurring organism that holds the record for living at the hottest temperature is Geogemma barossii, a single-celled organism that thrives in hydrothermal vents on the seafloor and can grow and reproduce at 121 degrees Celsius.
For more on otherworldly life, check out this video, and thank you for always coming back to Seeker for your science news updates.
Deep Biosphere – A region of the Earth’s crust that contains living organisms, extending deep below the surface. – Scientists are studying the deep biosphere to understand how life can exist in such extreme conditions.
Bacteria – Microscopic single-celled organisms that can be found in various environments, including soil, water, and living hosts. – Bacteria play a crucial role in decomposing organic matter and recycling nutrients in ecosystems.
Archaea – A group of single-celled microorganisms similar to bacteria but with distinct genetic and biochemical characteristics, often found in extreme environments. – Archaea are known to thrive in hot springs and salt lakes, where few other organisms can survive.
Organisms – Living entities that can carry out life processes such as growth, reproduction, and response to stimuli. – All organisms, from the smallest bacteria to the largest whales, depend on their environment for survival.
Microbes – Microscopic organisms, including bacteria, viruses, fungi, and protozoa, that can be found in almost every habitat on Earth. – Microbes are essential for processes like fermentation and nitrogen fixation in the soil.
Life – The condition that distinguishes living organisms from inanimate matter, characterized by growth, reproduction, and response to stimuli. – The discovery of life in the deep ocean vents has expanded our understanding of where life can exist on Earth.
Extreme – Conditions that are very harsh or severe, often beyond the usual range of environmental factors that most organisms can tolerate. – Some organisms have adapted to extreme temperatures, such as those found in polar ice caps or volcanic vents.
Environments – The surroundings or conditions in which an organism lives, including all living and non-living factors. – Different environments, like deserts and rainforests, support diverse forms of life adapted to their specific conditions.
Surface – The outermost layer or boundary of an object or area, such as the Earth’s crust or the skin of an organism. – The surface of the Earth is home to a wide variety of ecosystems, each with unique plant and animal life.
Scientists – Individuals who conduct research and experiments to increase knowledge and understanding of the natural world. – Scientists use advanced technology to explore the deep ocean and uncover new species of marine life.
