Geobiology

Geobiology is a field of scientific research that looks at how the Earth and living things work together. It studies how life and the planet have changed each other over millions of years. This field mixes ideas from biology, geology, and soil science to understand the history of life on Earth.

Most geobiology studies focus on tiny microorganisms and how they affect the chemicals and materials in soil and rocks. These studies happen where the land, air, water, and ice meet. Geobiology is different from biogeochemistry because it looks at how living things and the Earth affect each other over time.

The colorful microbial mats of Grand Prismatic Spring in Yellowstone National Park, USA. The orange mats are composed of Chloroflexia, "Cyanobacteria", and other organisms that thrive in the 70˚C water. Geobiologists often study extreme environments like this because they are home to extremophilic organisms. It has been hypothesized that these environments may be representative of early Earth.

Geobiologists use many tools to learn how life and the Earth are connected. They try to understand how the Earth has changed since life first began. Some geobiologists even study how humans are changing the Earth today.

Geobiology can help solve real-world problems. For example, some tiny living things can help clean up oil spills. This shows how important it is to understand living things and our planet.

History

The term geobiology was created by Lourens Baas Becking in 1934. He described it as studying how living things and the Earth are connected.

Baas Becking began writing his book Geobiologie in 1944. He wrote the whole book in just seven weeks. His ideas were influenced by earlier scientists like Martinus Beyerinck and Vladimir Vernadsky.

A microbial mat in White Creek, Yellowstone National Park, USA. Note the conical microstructure of the bacterial communities. These are hypothesized to be a living analogue of ancient fossil stromatolites. Each cone has an oxygen gas bubble on top, the product of oxygenic photosynthesis by cyanobacteria in the multi-species microbial mats.

The first lab dedicated to geobiology opened in Australia in 1965. Advances in geochemistry and genetics helped scientists study how life and Earth work together.

In the 1930s, Alfred Treibs found proof that oil comes from living things. Later, scientists found chemical signs of ancient life in rocks.

In 1977, Carl Woese discovered a new group of living things called the Archaea. By the 1990s, scientists could use genetics to study life and Earth together in new ways.

Today, geobiology has its own journals, conferences, textbooks, and university programs around the world.

Major geobiological events

The geologic timescale overlain with major geobiologic events and occurrences. The oxygenation of the atmosphere is shown in blue starting 2.4 Ga, although the exact dating of the Great Oxygenation Event is debated.

One of the biggest events in Earth's history was when tiny plants, called photosynthetic bacteria, began to fill the air with oxygen. This change, known as the oxygen catastrophe or Great Oxygenation Event, greatly affected life on our planet and how elements moved through the environment.

Later, life evolved from single cells to many-celled organisms, thanks to the oxygen in the air. This led to animals and plants appearing on land, which changed how rivers flow and how nutrients travel. Other important changes include termites moving soil, coral building reefs, and large animals spreading nutrients through their waste.

Important concepts

Geobiology studies how Earth and life interact. This field looks at how living things and our planet change each other over time.

Banded iron formation (BIF), Hammersley Formation, Western Australia

Life changes through evolution, which means new types of living things develop over time. As life evolves, it also changes the planet. For example, early bacteria changed Earth's air by adding oxygen. This allowed new kinds of life to develop.

Earth itself has always been changing. Its continents move, its air and water change, and its temperature shifts. These changes affect the kinds of life that can live there. By studying rocks and genes, scientists can learn about both Earth's past and the life that lived there long ago.

Methodology

A microbial mat growing on acidic soil in Norris Geyser basin, Yellowstone National Park, USA. The black top serves as a sort of sunscreen, and when you look underneath you see the green cyanobacteria.

Geobiology uses many tools to study how life and Earth work together. Scientists grow tiny living things in labs to learn how they live. They also look at the genes of these organisms to see how they are related. Using special microscopes, they can see these tiny creatures up close.

Scientists use special markers to track chemical reactions and study rocks to learn about past environments. They look for tiny fossils and study ancient magnetic fields to learn about Earth's history and how life has changed over time.

Sub-disciplines and related fields

Geobiology connects with many other areas of study. Some people see it as including older fields like biogeochemistry and paleontology, while others think it only covers newer research between these fields, like geomicrobiology.

Astrobiology

Astrobiology mixes geobiology with planetary science to explore life on other planets. It looks at how life might start from non-living materials, a process called abiogenesis. Astrobiologists also study what life needs and how we might find life elsewhere.

Biogeochemistry

Biogeochemistry combines biology, geology, and chemistry to study how elements like nitrogen and carbon move around the Earth. James Lovelock created the "Gaia hypothesis," which suggests Earth's living and non-living parts work together to keep conditions right for life.

Stromatolites in the Green River Shale, Wyoming, USA, dating to the Eocene

Geobiochemistry

Geobiochemistry focuses on how Earth's geology affects life's chemical processes. It links changes in life to changes in temperature, pressure, and Earth's chemistry.

Environmental microbiology

Microbiology studies tiny life forms that need a microscope to see. Environmental microbiology looks at these tiny organisms and their processes in nature. Microbial ecology is similar but often focuses more on how these organisms interact with each other and their environment.

Geomicrobiology and microbial geochemistry

A vertical cross section of a microbial mat containing different organisms that perform different metabolisms. The green are presumably cyanobacteria, and teepee-like microstructures are visible on the surface.

Geomicrobiology studies how tiny organisms, called microbes, interact with minerals. Microbial geochemistry looks at the same topic but uses geological and chemical methods. Together, they study how microbes, Earth, and environmental systems connect.

Molecular geomicrobiology

Molecular geomicrobiology studies geological processes at the level of DNA and proteins. Researchers study how microbes change rock into soil.

Organic geochemistry

Organic geochemistry studies organic molecules found in ancient rocks. These molecules, called molecular fossils, can stay preserved for billions of years. Scientists study these to learn about ancient life and processes like diagenesis.

Ediacaran fossils from Mistaken Point, Newfoundland. Ediacaran biota originated during the Ediacaran Period and are unlike most animals around today.

Paleontology

Paleontology is the study of fossils. It includes finding and understanding fossils, whether they are from tiny microbes or big dinosaurs. Micropaleontology is important for geobiology because tiny fossils and ancient structures called stromatolites help show when certain types of life first appeared.

Biogeography

Biogeography studies where living things live, both now and in the past. It looks at how organisms are spread out across the Earth.

Evolutionary biology

Evolutionary biology studies how life on Earth has changed and become diverse. It uses genetics, ecology, biogeography, and paleontology to look at ideas like natural selection and how new species form.

Ecohydrology

Ecohydrology studies how water and ecosystems interact. Scientists sometimes use stable isotopes of water to track where water comes from and how it moves.