Exposed concrete led to oxygen depletion within Biosphere 2

An artificial ‘lung’ protects the glass structures making up Biosphere 2

Although confined from much of the surrounding environment, B2 allows sunlight to enter, enabling its plants to engage in photosynthesis. Expansion chambers were built to protect the facility's integrity by managing changes in gas pressure resulting from temperature fluctuations.

As an experiment, the first B2 mission highlighted the challenges of isolated systems

Some argue that isolation from the outside world was compromised—making the experiment a failure—when a crew member was taken from Biosphere 2 for surgery and returned hours later. This position was strengthened when it was revealed that oxygen had been pumped into the facility.

Biosphere 2 gradually transformed into a lab modeling environmental disasters

Built to establish a self-sustaining habitat, the privately funded facility was taken over by Columbia University in 1995. Closed-system experiments were halted in favor of investigations focused on the effects of climate change, which continued after B2 was donated to the University of Arizona in 2011.

During the first Biosphere 2 mission, crew members lost 16% of their body weight

Food and oxygen shortages drove the "Biospherians" to split into two factions—one seeking to bring in outside resources and another aiming to maintain isolation for the experiment's integrity. Psychological stress was exacerbated further by the increasing prevalence of insect pests.

Biosphere 2 is the largest Earth science experiment ever built

The vivarium—an enclosed system including animals and plants—is sealed from below with 454 metric tons of stainless steel liner and includes an ocean habitat with more than 700,000 gallons of seawater. B2 is visited by 100,000 people yearly, including more than 10,000 K-12 students.

Before Biosphere 2, the Soviet BIOS-3 system tested semi-closed ecosystems

Built from 1965 to 1972, the habitat hosted 10 experiments with crews ranging from one to three individuals who had their air recycled by algae and grew their own wheat and vegetables. However, dried meats were routinely brought into the facility to balance crew members’ diets.

A basement of mechanical systems—collectively called the technosphere—supports B2

Twenty-six underground air handlers heat, cool, filter and manage the humidity of the air across the biomes of Biosphere 2. The above-ground Energy Center complex provides continuous power to these and other systems, including heating and cooling water for laboratory experiments and personal use.

Biological terraforming studies have been conducted at Biosphere 2

The experiments involve populating barren hillslopes within the Landscape Evolution Observatory with microbes that react with air and rock to produce molecules needed by more complex organisms. Mosses and other simple plants can then grow in these spaces, gradually making them more hospitable to humans.

Biosphere 2 revealed limitations in maintaining wildlife in unfamiliar environments

Trees appeared to become weak and more prone to breaking because a lack of wind caused them to no longer need to develop stress wood. The extinction of pollinators—potentially due to an explosion in the population of longhorn crazy ants—was also unexpected.

The history of Earth's breathable atmosphere, made possible by photosynthetic bacteria

Between 3.2 billion and 2.8 billion years ago, threadlike microorganisms called cyanobacteria began consuming available water vapor, carbon dioxide, and sunlight to produce oxygen. However, molecules released from Earth's interior by volcanoes consumed this oxygen via chemical reactions, preventing it from accumulating until volcanism had sufficiently decreased about 2.4 billion years ago.

As of 2025, scientists at B2 study the heat tolerance of cacao and coffee trees

The research at Biosphere 2 has led to the development of low-cost plant monitors, which can be provided to farmers worldwide to enable more precise monitoring of crops. Geodesic domes built within the ocean biome are used to investigate the best architectural structures for repopulating degraded reefs.

B2 models the interactions of air, water, soil, plants and microbes at the LEO

The Landscape Evolution Observatory at Biosphere 2 examines how factors such as climate change, water flow, weathering and community development impact landscape structures comprising 500 metric tons of crushed rock. Research is also conducted at biomes representing savannas, mangroves, coastal fog deserts, oceans and rainforests.

Astronauts on the International Space Station have tested an algae-powered bioreactor that converts carbon dioxide, water, and light into oxygen and edible, protein-rich biomass.

A prototype greenhouse for Biosphere 2 is now part of a test habitat for Mars

The Space Analog for the Moon and Mars combines the Test Module greenhouse with a workshop, kitchen, common area, sleeping quarters, and a yard that mimics lunar and Martian surfaces. A blind crew member in SAM’s first mission, Inclusion I, helped assess accessibility in potential future space habitats.

Read a firsthand account of a participant in the first Biosphere 2 mission

The first crew of “Biospherians” spent four months growing their own wheat and awaiting the ripening of tomatoes, onions, and peppers to make their own pizza. They also raised their own livestock, including chickens, pigs, and two goats named Milky Way and Stardust.

Oxygen is produced in the International Space Station from recycled water, which is split into hydrogen and oxygen gases using an electric current.

Early Earth lifeforms likely made energy via mineral reactions, not sunlight

Earth's initial atmosphere was filled with carbon dioxide, methane, and water, with most oxygen locked away in the rocky crust. Over time, bacteria evolved to slowly release that oxygen into the atmosphere by breaking down rock.

Take a series of virtual tours of Biosphere 2

The videos provide a 360-degree view of the indoor rainforest, ocean ecosystem, Landscape Evolution Observatory, and underground technosphere. A Google Maps Street View option is available to explore additional biomes, with each associated with a different floor level on the bottom right.

Questioning the results of life on K2-18b

An analysis of the atmosphere of an exoplanet called K2-18b identified the presence of biosignatures—molecules that are created by living things on Earth. This discovery may indicate life exists beyond Earth, but the lack of environmental data complicates the interpretation of results.

Inhabiting Mars without terraforming might be accomplished with 'worldhouses'

A network of interconnected, airtight bubbles would require several orders of magnitude fewer materials than those required to re-establish the entire planet's atmosphere to resemble Earth. However, the whole network would be compromised by a single micrometeor impact that destroys the air seal.

Since the Industrial Revolution, surface ocean waters have become 30% more acidic due to the absorption of carbon dioxide.

China developed an artificial closed ecosystem in preparation for a future lunar base

Yuegong-1, also known as Moon Palace 1, was a Beijing facility where volunteers simulated life on a colony and conducted experiments on bioregenerative life support systems to assess their viability in an off-Earth environment. The longest experiment at the 0.04-acre facility lasted 370 days.

An oxygen tank explosion forced Apollo 13 to abort its moon landing

The 1970 mission—intended to be the third lunar landing—forced astronauts Jim Lovell, Jack Swigert, and Fred Haise to focus solely on their survival. They engineered a makeshift filter to handle the carbon dioxide they produced, which exceeded the lunar module's capacity.

How specialized oxygen mixtures like heliox enable deep diving without feeling drunk

Beyond a depth of about 30 meters (98 feet), if divers are breathing surface air, which is about 78% nitrogen, underwater pressure forces more nitrogen into the bloodstream and induces nitrogen narcosis, whose symptoms resemble alcohol intoxication. Through saturation diving, where nitrogen is replaced with helium—an inert gas—deep divers can maintain cognitive function while working for extended periods.

Steve Bannon was made CEO of the company in charge of Biosphere 2 in 1994

After providing $200M to launch and upgrade B2 before its second mission, billionaire philanthropist Ed Bass appointed the future political strategist and then financial consultant to help find new investments and bring costs under control. Fearing interference from non-science experts, Biospherians from the first mission vandalized the project.

The ocean's ability to store carbon long-term is being hindered by marine heatwaves

More than 4,000 robotic floats with biogeochemical data sensors, including oxygen, pH, nitrate, suspended particles, chlorophyll, temperature, and conductivity, have been deployed as part of the Global Ocean Biogeochemical Array. They have identified changes to ecosystem structure affecting the ocean's ability to transport carbon from surface waters into the deep.

Agrivoltaic solutions are tested in the land around the Biosphere 2 complex

The experiments involve identifying conditions needed to grow plants beneath solar panels, which protect the plants from the harsh sunlight of the Arizona desert. Research includes a citizen science component, where satellite gardens have been installed in nearby high schools.

Evidence suggests the first cells on Earth were bacteria

About 4 billion years ago, these single-celled organisms harvested carbon dioxide and sunlight to produce their own food and oxygen, setting the stage for the evolution of oxygen-breathing life forms. Archaeabacteria, which thrive on inorganic molecules in extreme habitats on Earth today, were also among the earliest organisms.

Watch underwater photosynthesis make water look like champagne

In shallow waters where sunlight can reach, photosynthetic reactions absorb water and dissolved carbon dioxide, producing bubbles of oxygen at the surface of plants. As these bubbles rise to the water's surface, a fizzy appearance is created.

The setting of the comedy film ‘Bio-Dome’ was inspired by Biosphere 2

The film features characters played by Pauly Shore and Stephen Baldwin who accidentally lock themselves inside an experimental biosphere, mistaking it for a shopping mall, while searching for a bathroom. With a Rotten Tomatoes score of 4%, it is considered one of the best-worst movies of all time.

Wind helps trees develop resistance to collapse

Scientists at Biosphere 2 found that trees grew faster in the facility than those in the wild but collapsed more quickly when replanted outdoors. Researchers uncovered that trees build resistance when pushed and pulled due to wind stress, strengthening their foundational root systems.

Because various climate factors can affect the abundance of isotopes preserved in materials within the geologic record, these substances can serve as proxies for ancient climate conditions.

Learn about historical uses of bioremediation, the oldest cleanup method on Earth

Biochemical reactions that decompose complex molecules into simpler ones have occurred on Earth for as long as life has existed and have gradually transformed the planet into a celestial body that is increasingly habitable to greater biodiversity. Along the way, modern, human-made bioremediation techniques began to take shape in Santa Maria, California, in the 1960s.

In 2013, an astronaut's helmet began filling with water during a spacewalk

A leak in the cooling system of Luca Parmitano's spacesuit caused water to obscure his vision and silence his radio as the International Space Station entered Earth's shadow, forcing him to feel his way back to the airlock in darkness.

Carbon sinks absorb more greenhouse gases than they produce

The largest on Earth are oceans, which capture 25% of all carbon emissions and 90% of excess atmospheric thermal radiation while generating half of the world's oxygen. Wildfires and deforestation have reduced forests' net sink capacity, though fungi are believed to capture and store over a third of global carbon emissions.

Why the abundance of RuBisCO in photosynthetic cells may come from its inefficiency

Despite pulling about 115 billion tons of carbon dioxide from the atmosphere to build organic molecules each year, the enzyme instead binds oxygen at least one in five times, needlessly costing cells energy. To compensate for this and its processing of no more than 10 molecules per second—versus thousands processed by a typical enzyme—it's become the most abundant enzyme on Earth.

The cycling of carbon via tectonic activity may have facilitated life on Earth

Plates sinking into Earth’s mantle pull carbon from the surface, helping stabilize the atmosphere and climate by removing greenhouse gases from volcanic eruptions. At the same time, magma is a significant contributor of heavy metals and other crucial minerals for life to the surface.

Learn how environmental conditions are optimized to increase bioremediation efficacy

Through biostimulation, Indigenous microbes are provided with moisture, nutrients, or oxygen to prevent their death and ensure optimal progression of their biochemical reactions. Bioaugmentation can introduce new microbial cultures to target specific compounds not natively found in the environment, while landfarming can spread or aerate contaminated soil to improve access to contaminants.

The inhabitability of the Martian environment presents significant colonization risks

Terraforming the thin atmosphere, toxic dust, extreme cold, and lack of magnetic field is infeasible, given limitations to the size of what can be sent to Mars. NASA and SpaceX are instead exploring creating underground shelters.

O'Neill cylinders are free-space habitats that spin to create artificial gravity

Popularized in the 1970s by Princeton physicist Gerard K. O'Neill, the 15-mile-long structures would be manufactured from lunar and asteroid materials and house human colonies. His space colony ideas have since influenced works of science fiction.

The Amazon rainforest is considered the 'lungs of the Earth,' but it contributes less than a quarter of the oxygen of phytoplankton—microscopic plants, algae, and bacteria capable of photosynthesis.

Soil is the largest terrestrial carbon sink on the planet, storing almost twice as much carbon as the atmosphere and all living plants and animals combined.

How microbes limited the damage and helped clean up the Deepwater Horizon oil spill

A bloom estimated to contain about 100 sextillion microbial cells broke down much of the 4.1 million barrels of spilled crude oil into nontoxic compounds in what was one of the most significant bioremediations of a human-made disaster. The microbes involved acted similarly to the first patented genetically modified organism in US history: an oil-eating bacterium engineered in 1971.

Watch a demonstration of the greenhouse effect with carbon dioxide, where thermal energy is trapped by the gas within a container, causing the temperature to increase.

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

Structures from ancient Rome have endured for millennia because tiny pieces of lime in Roman concrete enabled it to self-heal and prevent cracks from spreading when exposed to water.

If Earth's water were suddenly replaced with air, forest fires would burn most of the world's vegetation within years.

Watch a time-lapse from space of photosynthesis across Earth

Using NASA satellite imagery, carbon absorption can be tracked and serves as a proxy for photosynthetic activity on land and in the oceans. Over the course of a year, seasonal changes can be observed as plants become dormant in the fall and active again in the spring.

Watch a visualization of the construction of Chernobyl's sarcophagus

Built to contain the remains of Reactor 4 after the nuclear disaster, the "shelter structure" was constructed from about 400,000 cubic meters of concrete—enough to fill 160 Olympic-sized swimming pools. Construction required vehicles and cranes modified with special shielding to protect workers.

As of 2025, humans have only dug 0.2% the way to Earth's center

The Kola Superdeep Borehole revealed two billion-year-old fossils and underground water, but the immense temperature and pressure prevented further tunneling. Beyond those depths, scientists know of Earth's interior by analyzing how seismic waves move.