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A false color composite of global oceanic and terrestrial photoautotroph abundance, from September 2001 to August 2017. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE.[citation needed]

The biosphere (from Ancient Greek βίος (bíos) 'life' and σφαῖρα (sphaîra) 'sphere'), also called the ecosphere (from Ancient Greek οἶκος (oîkos) 'settlement, house' and σφαῖρα (sphaîra) 'sphere'), is the worldwide sum of all ecosystems. It can also be termed the zone of life on the Earth. The biosphere (which is technically a spherical shell) is virtually a closed system with regard to matter,[1] with minimal inputs and outputs. Regarding energy, it is an open system, with photosynthesis capturing solar energy at a rate of around 100 terawatts.[2] By the most general biophysiological definition, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, cryosphere, hydrosphere, and atmosphere. The biosphere is postulated to have evolved, beginning with a process of biopoiesis (life created naturally from non-living matter, such as simple organic compounds) or biogenesis (life created from living matter), at least some 3.5 billion years ago.[3][4]

In a general sense, biospheres are any closed, self-regulating systems containing ecosystems. This includes artificial biospheres such as Biosphere 2 and BIOS-3, and potentially ones on other planets or moons.[5]

Origin and use of the term

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A beach scene on Earth, simultaneously showing the lithosphere (ground), hydrosphere (ocean) and atmosphere (air)

The term "biosphere" was coined in 1875 by geologist Eduard Suess, who defined it as the place on Earth's surface where life dwells.[6]

While the concept has a geological origin, it is an indication of the effect of both Charles Darwin and Matthew F. Maury on the Earth sciences. The biosphere's ecological context comes from the 1920s (see Vladimir I. Vernadsky), preceding the 1935 introduction of the term "ecosystem" by Sir Arthur Tansley (see ecology history). Vernadsky defined ecology as the science of the biosphere. It is an interdisciplinary concept for integrating astronomy, geophysics, meteorology, biogeography, evolution, geology, geochemistry, hydrology and, generally speaking, all life and Earth sciences.

Narrow definition

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Geochemists define the biosphere as being the total sum of living organisms (the "biomass" or "biota" as referred to by biologists and ecologists). In this sense, the biosphere is but one of four separate components of the geochemical model, the other three being geosphere, hydrosphere, and atmosphere. When these four component spheres are combined into one system, it is known as the ecosphere. This term was coined during the 1960s and encompasses both biological and physical components of the planet.[7]

The Second International Conference on Closed Life Systems defined biospherics as the science and technology of analogs and models of Earth's biosphere; i.e., artificial Earth-like biospheres.[8] Others may include the creation of artificial non-Earth biospheres—for example, human-centered biospheres or a native Martian biosphere—as part of the topic of biospherics.[9]

Earth's biosphere

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Overview

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Currently, the total number of living cells on the Earth is estimated to be 1030; the total number since the beginning of Earth, as 1040, and the total number for the entire time of a habitable planet Earth as 1041.[10][11] This is much larger than the total number of estimated stars (and Earth-like planets) in the observable universe as 1024, a number which is more than all the grains of beach sand on planet Earth;[12][13][14][15] but less than the total number of atoms estimated in the observable universe as 1082;[16] and the estimated total number of stars in an inflationary universe (observed and unobserved), as 10100.[17]

Age

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Stromatolite fossil estimated at 3.2–3.6 billion years old

The earliest evidence for life on Earth includes biogenic graphite found in 3.7 billion-year-old metasedimentary rocks from Western Greenland[18] and microbial mat fossils found in 3.48 billion-year-old sandstone from Western Australia.[19][20] More recently, in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.[21][22] In 2017, putative fossilized microorganisms (or microfossils) were announced to have been discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that were as old as 4.28 billion years, the oldest record of life on earth, suggesting "an almost instantaneous emergence of life" after ocean formation 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.[23][24][25][26] According to biologist Stephen Blair Hedges, "If life arose relatively quickly on Earth ... then it could be common in the universe."[21]

Extent

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Rüppell's vulture
Xenophyophore, a barophilic organism, from the Galapagos Rift

Every part of the planet, from the polar ice caps to the equator, features life of some kind. Recent advances in microbiology have demonstrated that microbes live deep beneath the Earth's terrestrial surface and that the total mass of microbial life in so-called "uninhabitable zones" may, in biomass, exceed all animal and plant life on the surface. The actual thickness of the biosphere on Earth is difficult to measure. Birds typically fly at altitudes as high as 1,800 m (5,900 ft; 1.1 mi) and fish live as much as 8,372 m (27,467 ft; 5.202 mi) underwater in the Puerto Rico Trench.[3]

There are more extreme examples for life on the planet: Rüppell's vulture has been found at altitudes of 11,300 metres (37,100 feet; 7.0 miles); bar-headed geese migrate at altitudes of at least 8,300 m (27,200 ft; 5.2 mi); yaks live at elevations as high as 5,400 m (17,700 ft; 3.4 mi) above sea level; mountain goats live up to 3,050 m (10,010 ft; 1.90 mi). Herbivorous animals at these elevations depend on lichens, grasses, and herbs.

Life forms live in every part of the Earth's biosphere, including soil, hot springs, inside rocks at least 19 km (12 mi) deep underground, and at least 64 km (40 mi) high in the atmosphere.[27][28][29] Marine life under many forms has been found in the deepest reaches of the world ocean while much of the deep sea remains to be explored.[30]

Under certain test conditions, microorganisms have been observed to survive the vacuum of outer space.[31][32] The total amount of soil and subsurface bacterial carbon is estimated as 5 × 1017 g.[27] The mass of prokaryote microorganisms—which includes bacteria and archaea, but not the nucleated eukaryote microorganisms—may be as much as 0.8 trillion tons of carbon (of the total biosphere mass, estimated at between 1 and 4 trillion tons).[33] Barophilic marine microbes have been found at more than a depth of 10,000 m (33,000 ft; 6.2 mi) in the Mariana Trench, the deepest spot in the Earth's oceans.[34] In fact, single-celled life forms have been found in the deepest part of the Mariana Trench, by the Challenger Deep, at depths of 11,034 m (36,201 ft; 6.856 mi).[35][36][37] Other researchers reported related studies that microorganisms thrive inside rocks up to 580 m (1,900 ft; 0.36 mi) below the sea floor under 2,590 m (8,500 ft; 1.61 mi) of ocean off the coast of the northwestern United States,[36][38] as well as 2,400 m (7,900 ft; 1.5 mi) beneath the seabed off Japan.[39] Culturable thermophilic microbes have been extracted from cores drilled more than 5,000 m (16,000 ft; 3.1 mi) into the Earth's crust in Sweden,[40] from rocks between 65–75 °C (149–167 °F). Temperature increases with increasing depth into the Earth's crust. The rate at which the temperature increases depends on many factors, including the type of crust (continental vs. oceanic), rock type, geographic location, etc. The greatest known temperature at which microbial life can exist is 122 °C (252 °F) (Methanopyrus kandleri Strain 116). It is likely that the limit of life in the "deep biosphere" is defined by temperature rather than absolute depth.[citation needed] On 20 August 2014, scientists confirmed the existence of microorganisms living 800 m (2,600 ft; 0.50 mi) below the ice of Antarctica.[41][42]

Earth's biosphere is divided into several biomes, inhabited by fairly similar flora and fauna. On land, biomes are separated primarily by latitude. Terrestrial biomes lying within the Arctic and Antarctic Circles are relatively barren of plant and animal life. In contrast, most of the more populous biomes lie near the equator.

Annual variation

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On land, vegetation appears on a scale from brown (low vegetation) to dark green (heavy vegetation); at the ocean surface, phytoplankton are indicated on a scale from purple (low) to yellow (high). This visualization was created with data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer.
On land, vegetation appears on a scale from brown (low vegetation) to dark green (heavy vegetation); at the ocean surface, phytoplankton are indicated on a scale from purple (low) to yellow (high). This visualization was created with data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer.

Artificial biospheres

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Biosphere 2
Biosphere 2 in Arizona

Experimental biospheres, also called closed ecological systems, have been created to study ecosystems and the potential for supporting life outside the Earth. These include spacecraft and the following terrestrial laboratories:

Extraterrestrial biospheres

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No biospheres have been detected beyond the Earth; therefore, the existence of extraterrestrial biospheres remains hypothetical. The rare Earth hypothesis suggests they should be very rare, save ones composed of microbial life only.[46] On the other hand, Earth analogs may be quite numerous, at least in the Milky Way galaxy, given the large number of planets.[47] Three of the planets discovered orbiting TRAPPIST-1 could possibly contain biospheres.[48] Given limited understanding of abiogenesis, it is currently unknown what percentage of these planets actually develop biospheres.

Based on observations by the Kepler Space Telescope team, it has been calculated that provided the probability of abiogenesis is higher than 1 to 1000, the closest alien biosphere should be within 100 light-years from the Earth.[49]

It is also possible that artificial biospheres will be created in the future, for example with the terraforming of Mars.[50]

See also

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References

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Biosphere

View on Grokipedia
from Grokipedia
The biosphere is the global sum of all ecosystems on , comprising the narrow zone where exists and interacts with the planet's physical environment, including all living organisms such as microorganisms, , animals, and humans, as well as the they produce. This layer extends vertically from approximately 8 kilometers above 's surface into the atmosphere to about 11 kilometers below in the ocean depths. It overlaps with the other major systems—the atmosphere, , and —forming a dynamic interface that sustains across diverse biomes like forests, grasslands, deserts, tundras, and aquatic environments. The concept of the biosphere originated in the late , when Austrian Eduard Suess coined the term in 1875 to describe "the place on Earth's surface where life dwells." This idea was later expanded by Russian scientist in the 1920s, who viewed the biosphere as a geochemical system driven by living organisms, transforming Earth's materials through processes like and cycling. Vernadsky's work emphasized the biosphere's role as a self-regulating entity, influencing fields such as and . The biosphere supports millions of and is crucial for Earth's , as biological processes within it—such as —produce oxygen, sequester carbon, and regulate by interacting with atmospheric gases and oceanic currents. These interactions make the biosphere integral to global environmental stability, with human activities increasingly impacting its balance through habitat alteration and . Ongoing monitors biosphere using to track , , and responses to environmental shifts.

Definition and History

Etymology and Origin

The term "biosphere" originates from the Greek words bios (βίος), meaning "life," and sphaira (σφαῖρα), meaning "sphere," reflecting the concept of the global envelope where life exists. Austrian Eduard Suess introduced the term Biosphäre in in his work on the structure of the , using it to describe the narrow zone on the planet's surface—encompassing the land, oceans, and lower atmosphere—where living organisms interact with their inorganic environment. Suess's formulation emphasized the geological context, viewing the biosphere as a thin, life-sustaining layer distinct from deeper structures like the . Precursors to Suess's coinage appeared in the early , notably in the work of French naturalist . In his 1802 book Hydrogéologie, Lamarck discussed the concept of the realm of living matter on as the aggregate of living bodies influencing geological processes, though without the broader inorganic integrations later developed by others. This early idea laid a foundational notion of life as a distinct planetary domain, influenced by emerging evolutionary thought, but it remained focused on biological entities rather than systemic interactions. The concept underwent significant expansion in the 1920s through the contributions of Russian geochemist , who transformed the biosphere into a dynamic geochemical system. In his seminal 1926 The Biosphere, Vernadsky portrayed life not merely as a passive occupant of the planet but as an active geological force capable of altering Earth's chemical composition, atmosphere, and surface through biogeochemical processes. He integrated Suess's geological framework with biochemical cycles, emphasizing living matter's role in transforming inert materials and maintaining planetary equilibrium. By the mid-20th century, the term evolved from its primarily geological roots toward broader ecological applications, influenced by advances in and global environmental studies. This shift, accelerated during the 1950s and 1960s through initiatives like the International Biological Program, reframed the biosphere as an interconnected network of ecosystems, energy flows, and , highlighting its role in sustaining life amid planetary-scale changes.

Definitions and Scope

The biosphere refers to the narrow zone of , , and atmosphere that supports , encompassing the thin layer where occurs, from the upper reaches of the to the of . This , often termed the "life-support zone," limits the biosphere to regions of active biotic processes, excluding vast lifeless expanses such as the deep mantle or the upper . It emphasizes the spatial confinement of to interfaces where energy, water, and nutrients interact to sustain organisms. In contrast, a broader interpretation views the biosphere as the integrated global ecological system comprising all living organisms and their interconnections with the , , and atmosphere, functioning as a dynamic entity that influences planetary conditions. This perspective, aligned with the proposed by , posits the biosphere as a self-regulating system that maintains Earth's through feedback mechanisms among biotic and abiotic components. The Encyclopedia of Earth adopts the narrower view, defining it strictly as the zone of life, while the framework expands it to a holistic, regulatory planetary layer. The scope of the biosphere includes diverse biomes and microbial communities, extending from deep subsurface lithotrophic in crustal rocks to airborne microbes in atmospheric aerosols and extremophiles in hypersaline or acidic environments. This encompasses terrestrial forests, oceanic pelagic zones, polar ice caps, and even transient forms in the lower atmosphere, highlighting the biosphere's role in global biogeochemical cycles without rigid vertical boundaries. Such inclusivity underscores the biosphere's adaptability across environmental gradients, integrating prokaryotes, eukaryotes, and viruses within a unified life-sustaining envelope.

Earth's Biosphere

Formation and Age

The formation of Earth's biosphere began shortly after the planet's accretion approximately 4.54 billion years ago, with the earliest evidence of life emerging around 3.7 billion years ago during the eon. This evidence consists of structures—layered microbial mats formed by ancient cyanobacteria-like prokaryotes—preserved in metasedimentary rocks from the Isua Supracrustal Belt in . These fossils represent the initial establishment of in shallow marine environments, where simple, single-celled organisms began interacting with the geochemical cycles of a young, volatile dominated by volcanic activity and a . Throughout the eon (roughly 4.0 to 2.5 billion years ago), the biosphere was characterized by anaerobic prokaryotes, including and , which relied on chemolithotrophic and anoxygenic photosynthetic metabolisms in an oxygen-scarce world. A transformative milestone occurred with the around 2.4 billion years ago, when oxygenic by led to the production and eventual atmospheric accumulation of free oxygen, fundamentally reshaping global conditions and enabling the diversification of metabolic pathways. This event, evidenced by banded iron formations and sulfur isotope excursions in rocks, marked the transition from a predominantly anaerobic biosphere to one capable of supporting aerobic respiration. Subsequent developments in the eon included the origin of eukaryotic cells around 2 billion years ago, likely through endosymbiotic events involving archaeal hosts and bacterial symbionts that gave rise to mitochondria. Multicellular life emerged approximately 600 million years ago in the period, as seen in fossil assemblages of soft-bodied organisms exhibiting coordinated cell differentiation. The biosphere's expansion onto land began around 470 million years ago during the period, with the colonization by early vascular and arthropods, facilitated by symbiotic fungi that enhanced nutrient uptake in terrestrial soils. As a dynamic intertwined with Earth's , the biosphere has endured for about 4 billion years, continuously evolving through geological and biological feedbacks.

Spatial Extent and Layers

The biosphere encompasses a thin shell around , with a vertical extent spanning approximately 20 kilometers from the deepest reaches of the to the upper . In the subsurface, extremophiles thrive up to about 5 kilometers deep within the , where microbial life persists in basaltic rocks under high pressure and limited nutrients. At the upper boundary, stratospheric microbes, including and fungal spores, have been detected as high as 10 kilometers altitude, though viable populations diminish rapidly above the . This narrow vertical profile highlights the biosphere's confinement to zones where liquid , sources, and suitable temperatures intersect. Horizontally, the biosphere blankets nearly all of Earth's surface, covering about 71% of the planet with aquatic environments while extending across continental landmasses, including diverse biomes from tropical rainforests to polar ice caps. Oceanic realms dominate this coverage, hosting the majority of in surface waters, deep-sea sediments, and hydrothermal vents, whereas terrestrial regions feature in soils, forests, and deserts. Sterile zones, such as the deep mantle beyond the crust, remain devoid of due to extreme and . This global distribution underscores the biosphere's in linking surface processes across vast scales. The biosphere integrates with other planetary spheres through distinct layers: the lithobiosphere at the interface of the crust and , where terrestrial organisms interact directly with rock and ; the hydrobiosphere encompassing all aquatic forms from freshwater to abyssal ; and the aerbiosphere comprising airborne microbes and aerosols in the lower atmosphere. These layers facilitate critical interactions with the , such as roots penetrating to access minerals and , which in turn rocks and cycle nutrients. Such overlaps enable the biosphere to influence and be influenced by geological processes, maintaining stability. Quantitatively, the biosphere's living contains approximately 550 gigatons of carbon, predominantly in and soil microbes, representing a minuscule fraction of Earth's total . Its overall , including subsurface, oceanic, and atmospheric components, accounts for approximately 1% of the planet's , emphasizing its delicate and localized nature amid the vast . These metrics illustrate the biosphere's efficiency in sustaining life despite its limited spatial footprint.

Temporal and Seasonal Variations

The biosphere exhibits notable annual variations in primary , driven primarily by fluctuations in solar radiation input. Global gross primary (GPP) experiences an approximate 5-10% interannual fluctuation, with peaks occurring during spring and summer in the respective hemispheres due to increased insolation and favorable growing conditions. In the , which accounts for the majority of terrestrial , these peaks align with extended daylight and warmer temperatures, enhancing photosynthetic activity across forests, grasslands, and croplands. Seasonal dynamics further shape the biosphere's temporal patterns, manifesting in synchronized biological responses across ecosystems. In temperate zones, leaf phenology— the timing of budburst, leaf expansion, and —regulates canopy development, with spring leaf-out boosting GPP by up to 50% in forests before autumnal shedding reduces it. Oceanic regions see seasonal algal blooms, particularly in nutrient-rich areas and polar seas, where proliferation in spring and summer can double local , contributing significantly to global carbon fixation. Animal migration patterns, such as those of birds, mammals, and fish, redistribute seasonally, concentrating resources in productive summer breeding grounds and dispersing during winter, thereby influencing trophic dynamics and nutrient transport across landscapes. Daily cycles underscore the biosphere's responsiveness to light and temperature rhythms. , the dominant process during daylight, peaks around midday when is maximal, driving net carbon uptake in vegetated areas. Conversely, nighttime respiration releases CO2, as and soils respire accumulated carbohydrates, resulting in a diurnal atmospheric CO2 swing of approximately 6 ppm at mid-latitude monitoring sites, reflecting the balance between daytime fixation and nocturnal efflux. On slightly longer timescales, climatic oscillations like El Niño-Southern Oscillation (ENSO) events impose abrupt variations. The 1997-98 El Niño, one of the strongest on record, reduced global net primary production (NPP) by more than 2 PgC per year through widespread droughts and altered precipitation, suppressing terrestrial GPP in tropical regions and disrupting oceanic . La Niña phases, by contrast, often enhance productivity via increased rainfall, though the net effect underscores the biosphere's sensitivity to such interannual perturbations.

Biosphere Dynamics

Energy Flow and Nutrient Cycling

The biosphere is sustained by the continuous flow of energy, primarily derived from solar radiation, which enters the system at an approximate rate of 3.8 × 10^{24} joules per year after accounting for Earth's absorption of incoming sunlight. This energy is captured through photosynthesis by autotrophs, such as plants and phytoplankton, with a global efficiency of about 1-2%, converting solar energy into chemical energy stored in biomass. The resulting organic matter forms the base of food webs, where energy transfers across trophic levels—producers, primary consumers, secondary consumers, and so on—following Lindeman's law, which posits that approximately 10% of energy from one level is available to the next after losses to metabolism, heat, and waste. Nutrient cycling complements energy flow by recycling essential elements through biotic and abiotic processes, ensuring the availability of building blocks for life. The involves fixation via , incorporating atmospheric CO_2 into organic compounds, and release through respiration and , with a global flux of approximately 120 gigatons of carbon (GtC) per year cycling through terrestrial and oceanic ecosystems. Similarly, the features biological and atmospheric fixation converting N_2 into usable forms like , followed by , assimilation, and back to N_2, supporting protein synthesis across ecosystems. The , lacking a significant gaseous phase, relies on rock to release into soils and waters, uptake by organisms, and eventual return via or runoff, with fluxes tightly linked to geological processes. Primary production metrics quantify these dynamics, where gross primary production (GPP) represents the total carbon fixed by , related to net primary production (NPP)—the biomass available to higher trophic levels—by the equation: GPP=NPP+Ra\text{GPP} = \text{NPP} + R_a Here, RaR_a denotes autotrophic respiration, the energy expended by producers for maintenance and growth. Disruptions to these cycles, as framed by planetary boundary models, highlight thresholds for and flows, beyond which stability is compromised due to excessive loading from natural and intensified processes. These flows and cycles interconnect to regulate Earth's ; for instance, oceans serve as a major , absorbing about 25% of anthropogenic CO_2 emissions through physical and biological pumps, thereby mitigating atmospheric buildup.

Biodiversity and Ecosystem Interactions

within the biosphere operates at three interconnected levels: , , and , each contributing to the resilience and functionality of life on . represents the variation in alleles and genotypes within individual , enabling to environmental changes and underpinning evolutionary processes. quantifies the number and variety of distinct , with estimates from 2011 indicating approximately 8.7 million eukaryotic exist globally, though approximately 2.3 million have been formally described and cataloged as of 2025. encompasses the array of habitats and biological communities, including major biomes such as , tropical rainforests, temperate broadleaf forests, grasslands, savannas, deserts, and boreal forests (), which collectively support distinct assemblages of adapted to specific climatic conditions. Ecosystem interactions highlight the interdependencies among organisms that sustain biosphere dynamics. Food webs depict interconnected trophic structures where energy transfers from producers like to consumers, including herbivores and predators, maintaining balance through predation and competition. Symbiotic associations, such as mycorrhizal networks linking plant roots with fungal hyphae underground, enable mutualistic nutrient sharing—fungi supply phosphorus and to in exchange for carbohydrates—enhancing stability and . exert outsized influence on community composition; for instance, the reintroduction of gray wolves (Canis ) to in 1995 regulated elk populations, reducing overbrowsing on vegetation and allowing riparian ecosystems to recover, thereby boosting overall . Global patterns of exhibit pronounced geographic variation, influencing interactions worldwide. The latitudinal diversity gradient shows increasing toward the , with tropical regions harboring over half of all terrestrial due to favorable temperatures, rainfall, and habitat complexity that promote . hotspots, like the of , concentrate unique taxa isolated by geographic barriers, where more than 90% of and approximately 96% of plant are found exclusively within its boundaries, fostering specialized interactions in rainforests and spiny thickets. Key metrics quantify these patterns and interactions for scientific analysis. The Shannon diversity index (H' = -\sum p_i \ln p_i, where p_i is the proportion of i) evaluates community structure by integrating and evenness, revealing higher complexity in diverse compared to uniform polar assemblages. Biomass distribution underscores the biosphere's foundational layers, with comprising roughly 80% of total global (approximately 450 gigatons of carbon), primarily in terrestrial forests, while microbes—, , and fungi—account for about 15% (around 80 gigatons of carbon), driving and availability essential for higher trophic levels.

Human Impacts and Management

Anthropogenic Influences

Human activities have profoundly altered the biosphere through , , , and , leading to widespread disruptions in ecosystems and . These influences, primarily intensified since the , have reduced the biosphere's capacity to sustain life and maintain ecological balance. is a primary driver of biosphere alteration, with alone resulting in the annual loss of approximately 10 million hectares of forest worldwide between 2015 and 2020. This loss, driven by , , and infrastructure development, fragments ecosystems and diminishes the vertical and horizontal extent of the biosphere, particularly in tropical regions where is highest. exacerbates this by converting natural lands into impervious surfaces; although urban areas currently cover less than 3% of Earth's terrestrial surface, their expansion contributes to habitat loss for 26-39% of assessed by encroaching on critical ecosystems. Pollution from human sources further degrades the biosphere by introducing contaminants that bioaccumulate and disrupt biological processes. In marine environments, plastics have been ingested by or entangled with over 800 species, leading to physical harm, reduced feeding efficiency, and toxicity that cascades through food webs. On land and in freshwater systems, —formed from and emissions—leaches essential minerals like calcium from soils, thereby disrupting cycles and impairing growth and health. Climate change, largely anthropogenic due to , is reshaping the biosphere's structure and function. Global warming has driven biome shifts poleward at an average rate of about 6 km per decade, as migrate to track suitable climates, resulting in novel compositions and potential mismatches in interactions. In oceanic realms, acidification from absorbed CO2 reduces seawater pH, impairing calcification rates and threatening ecosystems that support 25% of marine . Overexploitation, including unsustainable harvesting and the introduction of , accelerates biosphere degradation. Current rates of are 10 to 100 times higher than natural background rates, as documented in the 2019 IPBES Global Assessment, endangering stability and services. facilitates the spread of invasive alien species through and , with these non-native organisms outcompeting locals, altering habitats, and contributing to up to 40% of known extinctions in affected regions.

Conservation and Sustainability

Conservation efforts for the biosphere emphasize the establishment of protected areas to safeguard ecosystems and . As of 2024, approximately 17.6% of global terrestrial and inland water areas, along with 8.4% of marine areas, are conserved through protected areas and other effective area-based conservation measures. These targets build on the Aichi Biodiversity Targets set under the , which aimed for at least 17% terrestrial and 10% marine coverage by 2020. These efforts continue under the , which aims to protect 30% of Earth's land and ocean by 2030. National parks and similar reserves play a crucial role, covering about 15% of Earth's land and contributing significantly to the preservation of hotspots. International initiatives provide frameworks for coordinated action. The , signed in 1992 at the Rio Earth Summit, promotes the conservation of biological diversity, sustainable use of its components, and fair sharing of benefits from genetic resources, with 196 parties committed to its implementation. Complementing this are the United Nations Sustainable Development Goals (SDGs), particularly SDG 14, which focuses on conserving and sustainably using oceans, seas, and marine resources to reduce pollution and protect marine life, and SDG 15, which targets the sustainable management of forests, combating , halting , and preventing . Restoration techniques are vital for repairing degraded biosphere components and enhancing resilience. Reforestation initiatives, such as the Trillion Trees partnership led by , the , and WWF, aim to protect, restore, and grow one trillion trees by 2030 to support and combat through improved forest cover. Similarly, wetland rehabilitation restores hydrological functions and vegetation, turning these ecosystems into effective carbon sinks; studies show that restored s can sequester carbon rapidly, becoming net sinks within two years when vegetation cover exceeds 55%. These approaches not only rebuild habitats but also bolster the biosphere's capacity to mitigate human-induced pressures like habitat loss. Success in conservation is measured through standardized assessments. The evaluates the extinction risk of , providing a global that informs policy and tracks trends in decline, with over 172,600 assessed as of 2025. Additionally, the framework, proposed by Rockström et al. in 2009, defines nine biophysical thresholds—such as and biogeochemical flows—that delineate humanity's safe operating space within the system, guiding efforts to avoid irreversible environmental changes. These metrics enable monitoring of progress toward sustainable biosphere management.

Beyond Earth

Artificial Biospheres

Artificial biospheres are human-engineered, sealed environments designed to replicate the self-sustaining processes of 's biosphere, primarily for scientific on closed ecological systems and to develop technologies for long-duration missions. These systems aim to recycle air, , and nutrients while producing , drawing inspiration from natural nutrient cycles to achieve high degrees of closure and efficiency. One of the most ambitious examples is the project, a 3.14-acre sealed facility constructed in , and operational from 1991 to 1993. This structure housed diverse biomes including a , with , wetlands, savannah , , and intensive areas, supporting eight human inhabitants in a materially intended to demonstrate global ecological dynamics in miniature. The mission faced significant challenges, notably oxygen depletion that reduced levels to as low as 14.5% by 1993—equivalent to high-altitude conditions—partly due to unanticipated absorption by uncured surfaces, which bound oxygen and released , alongside excessive buildup from . Other notable projects include the European Space Agency's (Micro-Ecological Life Support System Alternative), initiated in 1995, which develops a compartmentalized closed-loop using microorganisms, , and animals to recycle into oxygen, water, and edible for . NASA's (CELSS) program, active since the 1980s, focuses on bioregenerative technologies for space habitats, integrating higher and microbial processes to regenerate air and water while producing food. Key components of these artificial biospheres emphasize resource recycling, with goals of 95% or higher efficiency in air and water systems through physicochemical and biological methods, such as algal photobioreactors for oxygen production and filtration for . Food production relies on hydroponic and aeroponic cultivation of crops like , potatoes, and soybeans, optimized to provide caloric needs in limited —typically requiring about 50 square meters per person for full dietary support. Lessons from these efforts highlight the fragility of closed systems, including persistent CO2/O2 imbalances driven by unforeseen chemical reactions and biological feedbacks, as well as the dominant role of and aquatic microbes in nutrient cycling, which can both stabilize and destabilize ecosystems. These insights have informed applications in , such as closed-loop farming techniques that enhance resource efficiency on , reducing waste and improving crop yields in controlled environments.

Extraterrestrial Possibilities

The search for extraterrestrial biospheres focuses on environments beyond Earth that could support microbial life, drawing from astrobiological evidence of liquid water, energy sources, and organic compounds. On Mars, the subsurface is a prime candidate due to its potential to harbor protected habitats from surface radiation. NASA's Perseverance rover, operational since 2021, has collected rock samples containing potential biosignatures, such as organic molecules and chemical patterns suggestive of ancient microbial activity, including possible remnants of methanogenic microbes that could have thrived in subsurface aquifers billions of years ago. These findings, analyzed through instruments like SHERLOC and PIXL, indicate that Mars may have once sustained a biosphere reliant on geochemical energy, though confirmation awaits sample return missions planned for the 2030s. Among the solar system's icy moons, subsurface oceans offer promising venues for biospheres insulated by thick shells. Jupiter's moon Europa harbors a global saltwater beneath its icy crust, estimated to contain more water than all of Earth's oceans combined, with potential hydrothermal vents providing chemical energy for life. NASA's mission, launched on October 14, 2024, completed a Mars flyby on March 1, 2025, and will conduct dozens of flybys starting in 2030 to map the surface, measure the ocean's salinity and depth via magnetic fields, and search for plume ejections that could sample subsurface materials for biosignatures like or isotopic anomalies. Similarly, Saturn's moon features a subsurface venting through south polar plumes of and particles, rich in hydrogen, methane, and complex organics that suggest methanogenic processes akin to Earth's deep-sea ecosystems. Cassini spacecraft flybys from 2008–2015 sampled these plumes, detecting molecular hydrogen as a key energy source for potential microbial life, while proposed future missions like the Enceladus Life Finder aim to directly analyze plume contents for cellular material. In September 2025, the selected as a target for its next large-class mission under the Voyage 2050 program to further investigate habitability. Beyond our solar system, exoplanets in —regions where stellar could sustain liquid water—represent vast possibilities for biospheric detection through atmospheric . The system, hosting seven Earth-sized planets around an star 40 light-years away, includes three in the habitable zone where rocky surfaces might support oceans or subsurface habitats. The (JWST) has begun observing these worlds, targeting gases such as oxygen (O₂) and (CH₄) imbalances that could indicate biological disequilibrium, as these molecules react quickly but persist in atmospheres influenced by life processes like or . Early JWST data from 2023–2025 on suggest thin atmospheres with potential for such gases, and as of November 2025, new observations continue to probe this possibility, with hints of an atmosphere raising hopes for habitability though abiotic sources must be ruled out via multi-wavelength . Astrobiological frameworks guide the probability and detection of extraterrestrial biospheres, emphasizing both microbial and intelligent variants. The , formulated in 1961, estimates the number of communicative civilizations in the by multiplying factors like rates, habitable fractions, and the longevity of technological societies, yielding results from near-zero to thousands depending on parameter values informed by exoplanet surveys. 's astrobiology program integrates this with observational data to refine estimates, highlighting how recent discoveries of thousands of exoplanets bolster the likelihood of life-bearing worlds. Complementing biosignature hunts, the Search for Extraterrestrial Intelligence (SETI) targets technosignatures—artificial signals or structures indicating advanced biospheres evolved into civilizations. Efforts by the and , using telescopes like the Allen Array and JWST, scan for narrowband radio signals, laser pulses, or megastructures, with recent AI-enhanced analyses of millions of stars yielding no confirmed detections but expanding search volumes exponentially.

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