Biosphere

Last updated

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. Seawifs global biosphere.jpg
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.

The biosphere (from Greek βίος bíos "life" and σφαῖρα sphaira "sphere"), also known as the ecosphere (from Greek οἶκος oîkos "environment" and σφαῖρα), is the worldwide sum of all ecosystems. It can also be termed the zone of life on 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 130 terawatts per year. [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]

Contents

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

A beach scene on Earth, simultaneously showing the lithosphere (ground), hydrosphere (ocean) and atmosphere (air) 90 mile beach.jpg
A beach scene on Earth, simultaneously showing the lithosphere (ground), hydrosphere (ocean) and atmosphere (air)

The term "biosphere" was coined by geologist Eduard Suess in 1875, which he defined 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

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.[ citation needed ]

Earth's biosphere

Age

Stromatolite fossil estimated at 3.2-3.6 billion years old Stromatolithe Paleoarcheen - MNHT.PAL.2009.10.1.jpg
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 [9] and microbial mat fossils found in 3.48 billion-year-old sandstone from Western Australia. [10] [11] More recently, in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. [12] [13] 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. [14] [15] [16] [17] According to biologist Stephen Blair Hedges, "If life arose relatively quickly on Earth ... then it could be common in the universe." [12]

Extent

Ruppell's vulture Ruppelsvulture.jpg
Rüppell's vulture
Xenophyophore, a barophilic organism, from the Galapagos Rift. XenophyophoreNOAA.jpg
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. [18] [19] [20] 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. [21]

Microorganisms, under certain test conditions, have been observed to survive the vacuum of outer space. [22] [23] The total amount of soil and subsurface bacterial carbon is estimated as 5 × 1017 g. [18] 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). [24] 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. [25] 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). [26] [27] [28] 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, [27] [29] as well as 2,400 m (7,900 ft; 1.5 mi) beneath the seabed off Japan. [30] 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, [31] 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 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), and 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. [32] [33]

Earth's biosphere is divided into a number of 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, while most of the more populous biomes lie near the equator.

Annual variation

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. Mollweide Cycle.gif
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

Biosphere 2 in Arizona Biosphere 2 4888964549.jpg
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

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. [37] On the other hand, Earth analogs may be quite numerous, at least in the Milky Way galaxy, given the large number of planets. [38] Three of the planets discovered orbiting TRAPPIST-1 could possibly contain biospheres. [39] 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. [40]

It is also possible that artificial biospheres will be created in the future, for example with the terraforming of Mars. [41]

See also

Related Research Articles

<span class="mw-page-title-main">Astrobiology</span> Science concerned with life in the universe

Astrobiology is a scientific field within the life and environmental sciences that studies the origins, early evolution, distribution, and future of life in the universe through investigating its deterministic conditions and contingent events. As a discipline, astrobiology is founded on the premise that life may exist beyond Earth.

<span class="mw-page-title-main">Extraterrestrial life</span> Life that did not originate on Earth

Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside of Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might range from simple forms like prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more advanced than humankind. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology.

<span class="mw-page-title-main">Extremophile</span> Organisms capable of living in extreme environments

An extremophile is an organism that is able to live in extreme environments, i.e. environments with conditions approaching or expanding the limits of what known life can adapt to, such extreme temperature, radiation, salinity, or pH level.

<span class="mw-page-title-main">Life</span> Matter with biological processes

Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energy transformation, and reproduction. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Biology is the science that studies life.

<span class="mw-page-title-main">Microorganism</span> Microscopic living organism

A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells.

<span class="mw-page-title-main">Panspermia</span> Hypothesis on the interstellar spreading of primordial life

Panspermia is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraft carrying unintended contamination by microorganisms. Panspermia is a fringe theory with little support amongst mainstream scientists. Critics argue that it does not answer the question of the origin of life but merely places it on another celestial body. It is also criticized because it cannot be tested experimentally.

<span class="mw-page-title-main">Geomicrobiology</span> Intersection of microbiology and geology

Geomicrobiology is the scientific field at the intersection of geology and microbiology and is a major subfield of geobiology. It concerns the role of microbes on geological and geochemical processes and effects of minerals and metals to microbial growth, activity and survival. Such interactions occur in the geosphere, the atmosphere and the hydrosphere. Geomicrobiology studies microorganisms that are driving the Earth's biogeochemical cycles, mediating mineral precipitation and dissolution, and sorbing and concentrating metals. The applications include for example bioremediation, mining, climate change mitigation and public drinking water supplies.

<span class="mw-page-title-main">Biogeochemical cycle</span> Chemical transfer pathway between Earths biological and non-biological parts

A biogeochemical cycle is the pathway by which a chemical substance cycles the biotic and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, hydrosphere and lithosphere. There are biogeochemical cycles for chemical elements, such as for calcium, carbon, hydrogen, mercury, nitrogen, oxygen, phosphorus, selenium, iron and sulfur, as well as molecular cycles, such as for water and silica. There are also macroscopic cycles, such as the rock cycle, and human-induced cycles for synthetic compounds such as polychlorinated biphenyls (PCBs). In some cycles there are reservoirs where a substance can remain or be sequestered for a long period of time.

<span class="mw-page-title-main">Life on Mars</span> Scientific assessments on the microbial habitability of Mars

The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms, but habitable conditions do not necessarily indicate life.

<span class="mw-page-title-main">Microbial ecology</span> Study of the relationship of microorganisms with their environment

Microbial ecology is the ecology of microorganisms: their relationship with one another and with their environment. It concerns the three major domains of life—Eukaryota, Archaea, and Bacteria—as well as viruses.

<span class="mw-page-title-main">Microbial mat</span> Multi-layered sheet of microorganisms

A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts. A few are found as endosymbionts of animals.

<span class="mw-page-title-main">Marine microorganisms</span> Any life form too small for the naked human eye to see that lives in a marine environment

Marine microorganisms are defined by their habitat as microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism is any microscopic living organism or virus, that is too small to see with the unaided human eye without magnification. Microorganisms are very diverse. They can be single-celled or multicellular and include bacteria, archaea, viruses and most protozoa, as well as some fungi, algae, and animals, such as rotifers and copepods. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses as microorganisms, but others consider these as non-living.

Directed panspermia is the deliberate transport of microorganisms into space to be used as introduced species on lifeless but habitable astronomical objects.

Biological dark matter is an informal term for unclassified or poorly understood genetic material. This genetic material may refer to genetic material produced by unclassified microorganisms. By extension, biological dark matter may also refer to the un-isolated microorganism whose existence can only be inferred from the genetic material that they produce. Some of the genetic material may not fall under the three existing domains of life: Bacteria, Archaea and Eukaryota; thus, it has been suggested that a possible fourth domain of life may yet be discovered, although other explanations are also probable. Alternatively, the genetic material may refer to non-coding DNA and non-coding RNA produced by known organisms.

The Deep Carbon Observatory (DCO) is a global research program designed to transform understanding of carbon's role in Earth. DCO is a community of scientists, including biologists, physicists, geoscientists and chemists, whose work crosses several traditional disciplinary lines to develop the new, integrative field of deep carbon science. To complement this research, the DCO's infrastructure includes public engagement and education, online and offline community support, innovative data management, and novel instrumentation development.

<span class="mw-page-title-main">Tanpopo mission</span> 2015–18 ISS astrobiology experiment

The Tanpopo mission is an orbital astrobiology experiment investigating the potential interplanetary transfer of life, organic compounds, and possible terrestrial particles in the low Earth orbit. The purpose is to assess the panspermia hypothesis and the possibility of natural interplanetary transport of microbial life as well as prebiotic organic compounds.

Astro microbiology, or exo microbiology, is the study of microorganisms in outer space. It stems from an interdisciplinary approach, which incorporates both microbiology and astrobiology. Astrobiology's efforts are aimed at understanding the origins of life and the search for life other than on Earth. Because microorganisms are the most widespread form of life on Earth, and are capable of colonising almost any environment, scientists usually focus on microbial life in the field of astrobiology. Moreover, small and simple cells usually evolve first on a planet rather than larger, multicellular organisms, and have an increased likelihood of being transported from one planet to another via the panspermia theory.

<span class="mw-page-title-main">Earliest known life forms</span> Putative fossilized microorganisms found near hydrothermal vents

The earliest known life forms on Earth are believed to be fossilized microorganisms found in hydrothermal vent precipitates, considered to be about 3.42 billion years old. The earliest time for the origin of life on Earth is at least 3.77 billion years ago, possibly as early as 4.28 billion years ago—not long after the oceans formed 4.5 billion years ago, and after the formation of the Earth 4.54 billion years ago. The earliest direct evidence of life on Earth is from microfossils of microorganisms permineralized in 3.465-billion-year-old Australian Apex chert rocks.

The deep biosphere is the part of the biosphere that resides below the first few meters of the surface. It extends down at least 5 kilometers below the continental surface and 10.5 kilometers below the sea surface, at temperatures that may reach beyond 120 °C, which is comparable to the maximum temperature where a metabolically active organism has been found. It includes all three domains of life and the genetic diversity rivals that on the surface.

References

  1. ↑ "Biosphere" in The Columbia Encyclopedia, 6th ed. (2004) Columbia University Press.
  2. ↑ Nealson, Kenneth H.; Zeki, S.; Conrad, Pamela G. (1999). "Life: past, present and future". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 354 (1392): 1923–1939. doi:10.1098/rstb.1999.0532. PMC   1692713 . PMID   10670014.
  3. 1 2 Campbell, Neil A.; Brad Williamson; Robin J. Heyden (2006). Biology: Exploring Life. Boston, Massachusetts: Pearson Prentice Hall. ISBN   978-0-13-250882-7. Archived from the original on 2014-11-02. Retrieved 2008-09-14.
  4. ↑ Zimmer, Carl (3 October 2013). "Earth's Oxygen: A Mystery Easy to Take for Granted". The New York Times . Archived from the original on 3 October 2013. Retrieved 3 October 2013.
  5. ↑ "Meaning of biosphere". WebDictionary.co.uk. WebDictionary.co.uk. Archived from the original on 2011-10-02. Retrieved 2010-11-12.
  6. ↑ Suess, E. (1875) Die Entstehung Der Alpen [The Origin of the Alps]. Vienna: W. Braunmuller.
  7. ↑ Möller, Detlev (December 2010). Chemistry of the Climate System . De Gruyter. pp.  118–119. ISBN   978-3-11-022835-9.
  8. ↑ Bebarta, Kailash Chandra (2011). Dictionary of Forestry and Wildlife Science. New Delhi: Concept Publishing Company. p. 45. ISBN   978-81-8069-719-7.
  9. ↑ Ohtomo, Yoko; Kakegawa, Takeshi; Ishida, Akizumi; Nagase, Toshiro; Rosing, Minik T. (8 December 2013). "Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks". Nature Geoscience . 7 (1): 25–28. Bibcode:2014NatGe...7...25O. doi:10.1038/ngeo2025.
  10. ↑ Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News . Archived from the original on 29 June 2015. Retrieved 15 November 2013.
  11. ↑ Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M. (8 November 2013). "Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia". Astrobiology . 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC   3870916 . PMID   24205812.
  12. 1 2 Borenstein, Seth (19 October 2015). "Hints of life on what was thought to be desolate early Earth". Excite . Yonkers, NY: Mindspark Interactive Network. Associated Press. Archived from the original on 1 October 2018. Retrieved 8 October 2018.
  13. ↑ Bell, Elizabeth A.; Boehnike, Patrick; Harrison, T. Mark; et al. (19 October 2015). "Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon". Proc. Natl. Acad. Sci. U.S.A. 112 (47): 14518–21. Bibcode:2015PNAS..11214518B. doi: 10.1073/pnas.1517557112 . PMC   4664351 . PMID   26483481. Early edition, published online before print.
  14. ↑ Dodd, Matthew S.; Papineau, Dominic; Grenne, Tor; Slack, John F.; Rittner, Martin; Pirajno, Franco; O'Neil, Jonathan; Little, Crispin T. S. (2 March 2017). "Evidence for early life in Earth's oldest hydrothermal vent precipitates" (PDF). Nature. 343 (7643): 60–64. Bibcode:2017Natur.543...60D. doi: 10.1038/nature21377 . PMID   28252057. S2CID   2420384. Archived (PDF) from the original on 23 July 2018. Retrieved 19 February 2019.
  15. ↑ Zimmer, Carl (1 March 2017). "Scientists Say Canadian Bacteria Fossils May Be Earth's Oldest". The New York Times . Archived from the original on 2 March 2017. Retrieved 2 March 2017.
  16. ↑ Ghosh, Pallab (1 March 2017). "Earliest evidence of life on Earth 'found". BBC News . Archived from the original on 2 March 2017. Retrieved 2 March 2017.
  17. ↑ Dunham, Will (1 March 2017). "Canadian bacteria-like fossils called oldest evidence of life". Reuters . Archived from the original on 2 March 2017. Retrieved 1 March 2017.
  18. 1 2 University of Georgia (25 August 1998). "First-Ever Scientific Estimate Of Total Bacteria On Earth Shows Far Greater Numbers Than Ever Known Before". Science Daily . Archived from the original on 10 November 2014. Retrieved 10 November 2014.
  19. ↑ Hadhazy, Adam (12 January 2015). "Life Might Thrive a Dozen Miles Beneath Earth's Surface". Astrobiology Magazine . Archived from the original on 12 March 2017. Retrieved 11 March 2017.{{cite web}}: CS1 maint: unfit URL (link)
  20. ↑ Fox-Skelly, Jasmin (24 November 2015). "The Strange Beasts That Live In Solid Rock Deep Underground". BBC Online . Archived from the original on 25 November 2016. Retrieved 11 March 2017.
  21. ↑ Briand, F.; Snelgrove, P. (2003). "Mare Incognitum? An overview". CIESM Workshop Monographs. 23: 5–27.
  22. ↑ Zhang, K. Dose; A. Bieger-Dose; R. Dillmann; M. Gill; O. Kerz (1995). A. Klein, H. Meinert, T. Nawroth, S. Risi, C. Stride. "ERA-experiment "space biochemistry"". Advances in Space Research. 16 (8): 119–129. Bibcode:1995AdSpR..16h.119D. doi:10.1016/0273-1177(95)00280-R. PMID   11542696.
  23. ↑ Horneck G; Eschweiler U; Reitz G; Wehner J; Willimek R; Strauch K. (1995). "Biological responses to space: results of the experiment "Exobiological Unit" of ERA on EURECA I". Adv. Space Res. 16 (8): 105–18. Bibcode:1995AdSpR..16h.105H. doi:10.1016/0273-1177(95)00279-N. PMID   11542695.
  24. ↑ Staff (2014). "The Biosphere". Aspen Global Change Institute . Archived from the original on 10 November 2014. Retrieved 10 November 2014.
  25. ↑ Takamia; et al. (1997). "Microbial flora in the deepest sea mud of the Mariana Trench". FEMS Microbiology Letters. 152 (2): 279–285. doi: 10.1111/j.1574-6968.1997.tb10440.x . PMID   9231422.
  26. ↑ "National Geographic, 2005". Archived from the original on 2012-08-22. Retrieved 2012-12-18.
  27. 1 2 Choi, Charles Q. (17 March 2013). "Microbes Thrive in Deepest Spot on Earth". LiveScience. Archived from the original on 2 April 2013. Retrieved 17 March 2013.
  28. ↑ Glud, Ronnie; Wenzhöfer, Frank; Middelboe, Mathias; Oguri, Kazumasa; Turnewitsch, Robert; Canfield, Donald E.; Kitazato, Hiroshi (17 March 2013). "High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth". Nature Geoscience . 6 (4): 284–288. Bibcode:2013NatGe...6..284G. doi:10.1038/ngeo1773.
  29. ↑ Oskin, Becky (14 March 2013). "Intraterrestrials: Life Thrives in Ocean Floor". LiveScience. Archived from the original on 2 April 2013. Retrieved 17 March 2013.
  30. ↑ Morelle, Rebecca (15 December 2014). "Microbes discovered by deepest marine drill analysed". BBC News . Archived from the original on 16 December 2014. Retrieved 15 December 2014.
  31. ↑ Szewzyk, U; Szewzyk, R; Stenstrom, TR. (1994). "Thermophilic, anaerobic bacteria isolated from a deep borehole in granite in Sweden". Proceedings of the National Academy of Sciences of the USA. 91 (5): 1810–1813. Bibcode:1994PNAS...91.1810S. doi: 10.1073/pnas.91.5.1810 . PMC   43253 . PMID   11607462.
  32. ↑ Fox, Douglas (20 August 2014). "Lakes under the ice: Antarctica's secret garden". Nature . 512 (7514): 244–246. Bibcode:2014Natur.512..244F. doi: 10.1038/512244a . PMID   25143097.
  33. ↑ Mack, Eric (20 August 2014). "Life Confirmed Under Antarctic Ice; Is Space Next?". Forbes . Archived from the original on 22 August 2014. Retrieved 21 August 2014.
  34. ↑ Salisbury FB; Gitelson JI; Lisovsky GM (Oct 1997). "Bios-3: Siberian experiments in bioregenerative life support". BioScience. 47 (9): 575–85. doi: 10.2307/1313164 . JSTOR   1313164. PMID   11540303.
  35. ↑ Nakano; et al. (1998). "Dynamic Simulation of Pressure Control System for the Closed Ecology Experiment Facility". Transactions of the Japan Society of Mechanical Engineers Series B. 64 (617): 107–114. doi: 10.1299/kikaib.64.107 . Archived from the original on 2012-03-18. Retrieved 2009-11-14.
  36. ↑ "Institute for Environmental Sciences". Ies.or.jp. Archived from the original on 2011-11-08. Retrieved 2011-11-08.
  37. ↑ Ward, Peter D.; Brownlee, Donald (2004). Rare earth: why complex life is uncommon in the universe (2nd rev. ed.). New York: Copernicus. ISBN   978-0-387-95289-5.
  38. ↑ Choi, Charles Q. (21 March 2011). "New Estimate for Alien Earths: 2 Billion in Our Galaxy Alone". Space.com. Archived from the original on 24 August 2017. Retrieved 25 September 2017.
  39. ↑ Rees, Sir Martin (22 February 2017). "These new worlds are just the start. There are many more life-supporting planets out there waiting to be discovered". The Telegraph. Archived from the original on 25 September 2017. Retrieved 25 September 2017.
  40. ↑ Amri Wandel, On the abundance of extraterrestrial life after the Kepler mission Archived 2018-08-17 at the Wayback Machine
  41. ↑ Zubrin, Robert; Wagner, Richard (2011). The Case for Mars: The Plan to Settle the Red Planet and Why We Must. Simon & Schuster. ISBN   978-1451608113.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.