Biological Complexity and Biosphere 2
Exam date and scope: September 24; modules one and information literacy; focus framed through White-nose syndrome (a fungal disease affecting North American bat populations).
Transition to Biosphere 2: a field-trip-style section focusing on a large, sealed ecological research facility in Southern Arizona; context provided for ecological concepts via a real-world example.
Biosphere 2 location and scale:
Located north of Tucson, near the Catalina Mountains; elevation ~4,000 ft; mountains reach ~11,000 ft (Bigelow is ~11k ft).
Described as one of the largest greenhouses by volume; an enormous, multi-biome enclosure used to study biomes, ecosystems, and nutrient cycling.
Inside Biosphere 2 are several biomes in separate bays, including a desert biome, savannah biome, the world’s highest elevation saltwater body, an ocean, a rainforest, and a large agricultural complex.
The living habitat includes laboratories, living quarters, kitchens, medical facilities; built in the late 1980s–early 1990s.
The structure is designed to test whether a closed or semi-closed habitat can sustain human life for extended periods (original plan: three years of self-sustained living).
The facility is enclosed by glass; UV-absorbing glass reduces need for sunscreen and affects working conditions in the desert biome.
Notable design elements and terminology:
The facility’s “lung”: a large balloon-like volume that inflates during daytime as air expands and deflates at night when air cools, due to temperature-driven volume changes in a sealed environment.
Aesthetic and cultural context: described as visually reminiscent of Star Trek Next Generation interiors (mauve/maroon pastel tones; a “time capsule” look).
Founding and funding:
Built with private funding by Ed Bass, an eccentric billionaire with wealth from oil and real estate.
The project’s intent: explore if a self-contained ecosystem could simulate space-travel life-support and yield insights into carbon, water, and nutrient cycling.
History of management and ownership:
Biosphere 2 passed from private funds to Columbia University (Ivy League) for research.
Later, Columbia transferred the facility to the University of Arizona; it remains there as a combination educational and scientific facility.
Today, Biosphere 2 operates as both an educational site and a scientific campus; tickets are sold for tours.
Personal anecdote and field experience (instructor’s perspective):
Worked at Biosphere 2 post-PhD during a postdoctoral appointment at UC Irvine; PhD advisor Travis Huxman (then director of Biosphere 2) connected the instructor’s group.
Research conducted: how different plant species respond to temperature regimes within the biosphere; demonstrates the facility’s capability to precisely control climate in connected biomes.
Interactions with visitors: tours entered every ~30 minutes; researchers sometimes felt observed; after initial awkwardness, crowds became routine; compared experience to open-kitchen work environments.
Practicalities of research and operation:
Biosphere 2’s scale allows deliberate manipulation of the environment: e.g., cooling the savannah a few degrees during the day, warming the desert, etc.
The setting functions as a research campus with guesthouses for researchers and staff.
There are ongoing discussions about the original project’s motives and outcomes, including debates about publicity and the project’s ultimate scientific value.
Human health and nutrition within Biosphere 2 (historical observations):
An emergency evacuation occurred after an injury to a crew member; the individual needed hospitalization, complicating the sealed environment’s integrity.
In the nine-month experiment, crew members lost an average of about 30 pounds, largely due to insufficient rapid food production within the bays.
Ecosystem concepts and definitions (as introduced in the lecture):
Biosphere 2 demonstrates a closed-system approach to matter; energy flows in and out via solar input while matter cycles internally.
The Earth is described as materially closed for most practical purposes: nothing significant enters or leaves the system (except trace cometary water, which is minuscule relative to Earth’s total water mass).
Energetic openness: the Sun continuously injects energy; some energy is reflected, some absorbed and re-emitted as heat; matter cycles within the system.
Hierarchy of biological organization (as presented):
Biosphere (the largest unit of life on Earth)
Biomes (regions with distinct climates and distinctive plant/animal assemblages)
Ecosystems (living and nonliving components interacting within a biome)
Communities (the living portion of ecosystems; all populations interacting in an area)
Populations (groups of individuals of the same species that can breed amongst each other)
Species (groups of organisms with high similarity that can generally interbreed)
Individuals (single organisms)
Habitat (the physical environment where a species is found)
Niche (the role a species plays in its community, including energy/nutrient acquisition, habitat needs, and interactions with other species)
Key terms and clarifications:
Ecosystem: a slippery concept; a concrete working definition is a specific portion of a biome including living (biotic) and nonliving (abiotic) components interacting with one another.
Species: a group with high similarity that can generally interbreed; multiple definitions exist in evolutionary biology, hence “slippery” in practice.
Habitat vs niche: habitat is the physical environment; niche is the “job” or functional role within the ecosystem (how energy and nutrients are obtained, what resources are required, and how it interacts with other species).
Biomes and their representative examples discussed:
Desert: warm winters, hot summers; receives precipitation in both winter and summer; Sonoran Desert (Southern Arizona) highlighted; notable for high plant diversity including Saguaro cacti; dry conditions with dual rainy seasons.
Savanna: scattered trees with a grassland understory (iconic in East Africa, Maasai Mara).
Tropical rainforest: warm and wet year-round; high biodiversity.
Boreal forest (taiga): cold, with conifers such as spruce; located in northern latitudes; requires flight north into Canada to access; limited population density relative to temperate regions.
Tundra: cold and often dry; high latitudes.
Mediterranean scrub: warm, dry summers and cool, wet winters; geographically dispersed (around the Mediterranean, California, Chile, parts of South Africa, Australia); named for climate rather than proximity to the sea.
Temperate forest and temperate grassland: discussed in context of Buffalo, NY mean annual temperature ~9°C and mean annual precipitation ~102 cm; map interpretation used to deduce likely biome.
Climate axes and data interpretation:
Biomes defined by mean annual temperature (°C) and mean annual precipitation (cm); the axes are conceptually used to map biomes to climatic space.
Temperature conversion reference: room temperature in the classroom ~22°C (approx. 72°F); freezing point is 0°C.
Mean annual temperature: the average of daily temperatures over a year, i.e., T{mean} = rac{1}{365} rac{ ext{sum of daily temps}}{1} ightarrow T{mean} = rac{1}{365} igg(
ext{sum}{d=1}^{365} Td igg)
Precipitation units: cm of water per year, with 100 cm = 1 m; some biomes receive as much as 450 cm/year (4.5 m).
Graphical and map observations discussed:
The biome map ignores oceans and focuses on terrestrial biomes; this is a limitation when considering a truly planetary perspective.
Human activity has massively transformed terrestrial environments; the map reflects natural vegetation but not modern anthropogenic changes (agriculture, urbanization, etc.).
Deserts occupy a wide temperature range, from around -5°C to about 30°C, making packing difficult for travel.
Temperate forests and grasslands occupy mid-range temperature and precipitation bands and are common around populated areas; Buffalo-Minneapolis corridor is used as a real-world example that shows agricultural land (corn and soybeans) dominating the landscape rather than broad grassland.
Important pedagogical points and discussion prompts:
Why aren’t all biomes found everywhere? The combination of climate (temperature and precipitation), geography, and human influence explains biome distribution.
The concept of scale: defensible boundaries for ecosystems are slippery; biomes are broad, whereas ecosystems are local and context-dependent.
The relationship between climate space and biome distribution is a key tool in environmental science and geography; mapping climate to biomes helps with travel planning, conservation, and understanding ecological constraints.
Practical implications and reflections:
Biosphere 2 as a testbed for closed-system ecology provides insight into how near-Earth habitats might be managed for long-duration spaceflight or remote sustainability projects.
The ethical and practical considerations of private funding in science (boondoggle vs. genuine research) and the tension between publicity and scientific value.
The instructor’s experiences underscore the human dimension of fieldwork: working in a highly public setting, balancing science communication with research objectives, and managing the social dynamics of a high-visibility project.
Real-world relevance and connections:
The discussion ties to foundational ecology concepts: energy flow, matter cycling, and the organization of life from individuals to biosphere.
The exercise of reading a biome map reinforces how climate variables structure ecological communities and how human actions modify these patterns.
The biosphere framework links to broader questions about sustainability, climate change adaptation, and the design of artificial ecosystems for space or extreme environments.
Summary takeaways:
Biosphere 2 demonstrated the feasibility and challenges of a closed, human-contained ecological system with multiple biomes; it highlighted both the potential and limitations of such experiments for understanding Earth systems.
Key ecological concepts—biosphere, biome, ecosystem, habitat, population, species, community, individual, and niche—provide a scalable framework for thinking about life-supporting systems and how organisms interact with their environment.
Climate is a primary driver of biome distribution, but modern human activities can alter those patterns, complicating simple climate-to-biome predictions.
Notable numerical references for study:
Biosphere 2 construction period: late 1980s–early 1990s
Desert biodiversity example: Sonoran Desert (Southern Arizona)
Biome dimensions: some agricultural bays are “as big as the biggest cathedral,” illustrating enormous scale; a seven-story-tall enclosed forest canopy in some biosphere sections
Mean annual temperature benchmarks: room temperature ≈ T{room} \approx 22^{\circ}C; freezing point T{freeze}=0^{\circ}C
Precipitation scale: from near 0 cm/year to about 450 cm/year; 1 m = 100 cm
Population-level effects in the private-venture Biosphere 2: observed average weight loss of ~30 pounds over the nine-month run
Hypothetical scenarios and thought prompts included in the talk:
If engineers could tune temperatures in each biome by a few degrees for a sustained period, what would be the cascading effects on plant growth, water use, and nutrient cycling?
How would one design a robust monitoring regime to distinguish climate-driven changes from other stressors inside a closed system?
Consider the ethical implications of privately funded experiments that aim to simulate Earth-system processes; how should transparency and public benefit be weighed against private investment and publicity?
Quick glossary (for study):
Biosphere: the global sum of all living systems; the largest biological unit.
Biome: large geographic biotic units defined by climate and dominant vegetation (e.g., tundra, boreal forest, deserts, tropical rainforest, Mediterranean scrub).
Ecosystem: a biotic-abiotic network within a biome; includes living and nonliving components interacting in a system.
Habitat: the physical location or environment where a species lives.
Niche: the functional role of a species within its ecosystem, including energy acquisition, resource use, and interactions with other species.
Population: individuals of the same species that can interbreed.
Community: the assemblage of all populations (the living component) within a given area.
Individual: a single organism within a population.
Final reminder from the session: The class will revisit these ideas with more problem-solving (e.g., boundary-drawing exercises, biome classification based on climate data) in upcoming meetings.” ,