Exploring the intricate relationship between humans and ecosystems through the lens of the Biosphere 2 experiment
Imagine spending two years locked inside a giant, sealed glass structure containing miniature replicas of Earth's ecosystems—a tropical rainforest, a desert, an ocean with a coral reef. This wasn't a science fiction movie but a groundbreaking experiment called Biosphere 2 that unfolded in the Arizona desert in the early 1990s1 . Eight people entered this enclosed world to test whether humans could create and maintain a self-sustaining environment separated from Earth's natural systems—a capability that might one day be essential for space colonization1 .
What happened next would reveal profound lessons about human ecology—the study of how humans interact with their social and physical environments7 . The Biosphere 2 experiment demonstrated with startling clarity that we are deeply embedded within ecological systems rather than separate from them, and that these relationships are far more complex than we typically appreciate.
As we face escalating environmental challenges on our own Biosphere 1 (Earth), understanding these intricate connections has never been more critical.
This article explores the fascinating science of human ecology, from its theoretical foundations to its practical applications. We'll examine what the Biosphere 2 experiment taught us about the fragility of our relationship with natural systems, investigate the tools scientists use to study these connections, and discover emerging approaches that blend Western science with Indigenous wisdom to reimagine a sustainable human ecology.
Human ecology emerged as a distinct field in the 1920s when sociologists from the Chicago School began applying ecological concepts like community, competition, and succession to human societies7 . They observed similarities between the struggle for existence that Charles Darwin documented in nature and the social dynamics of immigrant communities adapting to American cities7 .
Recognizes humans as one species among many that interact with bounded environmental conditions7 .
Emphasizes complexity and change in relationships between people, organisms, and environments7 .
Bronfenbrenner's model showing human development across multiple environmental systems8 .
| System Level | Definition | Example Influences |
|---|---|---|
| Microsystem | Immediate settings containing the developing person | Family, school, workplace |
| Mesosystem | Interconnections between microsystems | Parent-teacher relationships |
| Exosystem | External settings that indirectly affect development | Parent's workplace, school board policies |
| Macrosystem | Overarching patterns of culture and society | Societal values, economic systems, belief systems |
The field continues to evolve, incorporating new understandings from across disciplines. Unlike purely mechanistic views of nature that dominated the Scientific Revolution, human ecology recognizes that living systems cannot be fully understood by breaking them down into their constituent parts. Instead, it embraces a holistic perspective that acknowledges the emergent properties that arise from complex interactions.
In September 1991, eight "biospherians" entered a massive sealed structure in the Arizona desert designed to be an entirely closed ecological system1 . The $150 million facility covered three acres (1.2 hectares) and contained meticulously engineered replicas of several Earth ecosystems1 :
With a 25-foot (7.6m) waterfall
Arid and semi-arid environments
Mangrove-studded wetland ecosystem
Larger than an Olympic swimming pool
Despite meticulous planning, the experiment encountered serious challenges that revealed unexpected complexities in ecological relationships:
Oxygen levels dropped from the normal 21% to just 14%—equivalent to elevation at 3,350 meters (11,000 feet)—causing altitude sickness, fatigue, and making physical labor arduous1 .
CO2 levels spiked unpredictably, partly buffered by an unforeseen sink: the facility's concrete structures absorbed excess CO21 .
Most pollinating insects went extinct, threatening plant reproduction1 . Many trees became weak and prone to breaking because the enclosed environment lacked wind1 .
The biospherians lost significant weight despite their farming efforts, becoming a case study in calorie restriction1 .
| Problem Area | Consequence | Eventual Understanding |
|---|---|---|
| Oxygen depletion | Levels dropped to 14%, causing health issues | Microbial activity in rich soils outpaced plant oxygen production |
| CO2 fluctuations | Dangerous spikes in greenhouse gas | Concrete surfaces unexpectedly absorbed CO2, providing partial buffering |
| Pollinator extinction | Threatened plant reproduction | Ant overpopulation and lack of UV light disrupted insect ecology |
| Structural weakness in plants | Trees became prone to breaking | Lack of wind prevented development of strengthening "stress wood" |
Estimated monthly cost per person to provide comparable ecosystem services in space colonies1
Although initially dismissed by many as a failure, Biosphere 2 is now recognized as a pioneering experiment in closed ecological systems1 . It generated invaluable insights:
Revealed the critical importance of normally invisible soil microbiomes for atmospheric regulation1 .
Demonstrated unexpected ways that built environments interact with biological systems1 .
Underscored the immense difficulty of replicating Earth's ecosystem services1 .
"I firmly believe that this really is our only planet ever" - David Tilman, ecologist1
Perhaps the most profound lesson was summarized by ecologist David Tilman: "I firmly believe that this really is our only planet ever"1 . The experiment transformed how participants viewed their relationship with nature, as one biospherian noted: "Just being in a small system where you see that reality—that you're part of that system, and that system is your life support—changes the way you think at a very deep level"1 .
Studying human-environment interactions requires diverse methodological approaches. Ecologists generally employ three broad research strategies, each with particular strengths for investigating different aspects of complex systems5 .
| Method | Description | Application Example |
|---|---|---|
| Observation and Field Work | Documenting species and environments in their natural state through direct or indirect surveys | Tracking population changes, studying community ecology, environmental impact assessments |
| Experimentation | Manipulative, natural, or observational experiments to test specific hypotheses | Reintroducing species to observe ecosystem effects, testing responses to controlled changes |
| Modeling | Using mathematical and statistical models to predict ecosystem changes over time or in response to changing conditions | Climate change projections, population dynamics, analyzing systems too complex for traditional methods |
Organizations like the Ecology Center's Healthy Stuff Lab engage communities in designing studies about chemical hazards in water, air, soil, and consumer products3 . This approach shifts power dynamics inherent in traditional institutional research.
Tools like X-ray Fluorescence (XRF) analyzers and Fourier Transform Infrared Spectrometers (FTIR) help identify chemical hazards in environments and products3 .
Methods for studying complex interactions across multiple scales, from microscopic chemical analyses to global climate modeling.
These diverse tools and methods allow human ecologists to study complex systems across multiple scales, from microscopic chemical analyses to global climate modeling.
Contemporary human ecology is increasingly embracing Indigenous knowledge systems and systems thinking to address the limitations of Western scientific paradigms.
Australian Aboriginal belief systems, for instance, maintain a sophisticated understanding of dynamic equilibrium through reciprocal relationships based on deep ecology and interconnection between all living things. This perspective is embodied in the four pillars of Kanyini: Ngurra (home), Walytja (family), Kurunpa (spirit), and Tjukurpa (Knowledge of creation or Dreaming).
Home or country - connection to land
Family and kinship relationships
Spirit, soul or essence
Dreaming or creation knowledge
Historical accounts now recognize that many Indigenous communities practiced sophisticated ecological management long before European colonization. Writer Bruce Pascoe documents extensive aquaculture and food preservation practices in Australia that preceded colonisation, challenging the hunter-gatherer myth that was traditionally taught.
Systems thinkers like Fritjof Capra and Pier Luigi Luisi argue that a poverty of perception exists in Western culture due to reductionist thinking—the tendency to break complex systems down into their parts rather than understanding them as wholes. They trace this to the rise of a mechanistic worldview during the Scientific Revolution that viewed living things as automata and nature as a clockwork universe.
There is growing recognition that education must better embed these broader perspectives. Heather ahtone (Choctaw/Chickasaw) describes the distinction between Western paradigms that interpret aesthetics as value ascribed to human products, versus Indigenous perspectives of aesthetics as "tribally-specific systems grounded in epistemological cosmologies".
This points toward developing eco-aesthetics—an approach to learning that is both relational and immersive, helping students overcome what researchers call "plant blindness," the inability to see or notice plants in one's own environment. Such approaches aim to restore what ancient Greek philosophy originally meant by aesthetics—"to perceive through all the senses".
The Biosphere 2 experiment ultimately taught us that our own Biosphere 1 is far more complex, resilient, yet fragile than we often appreciate. What initially appeared as a failure of a sealed ecosystem became a powerful demonstration of the irreplaceable services that natural systems provide humanity—from oxygen production to pollination, water purification to waste decomposition1 .
As we face the growing challenges of climate change, biodiversity loss, and environmental degradation, human ecology offers crucial insights for creating sustainable relationships with our planetary home. It reveals that technical fixes alone are insufficient—we need deeper transformations in how we perceive and value natural systems.
The path forward likely integrates the best of Western science with the wisdom of Indigenous knowledge systems, combining technological innovation with a renewed ethical orientation toward reciprocity and balance. As one Biosphere 2 participant reflected, understanding that our ecosystems are our life support changes how we think at a profound level1 . This shift in perspective—from seeing ourselves as separate from nature to recognizing our embeddedness within it—may be the most important step toward creating a sustainable human ecology for future generations.
"Just being in a small system where you see that reality—that you're part of that system, and that system is your life support—changes the way you think at a very deep level"1