Endoliths are organisms ( archaea , bacteria , fungi , lichens , algae , amoeba ) that live inside stones, corals , shells of animals or in the pores between particles of stone. Many are extremophiles and live in places that at first seem inhospitable to living organisms. They are of particular interest to astrobiologists who construct theories that the endolithic habitats of Mars and other planets can represent potential refugia (shelters) for interplanetary microbial communities [1] .
Content
- 1 Divisions
- 2 Habitats
- 3 Survival
- 4 Power
- 5 notes
- 6 See also
Units
The following 3 groups of endoliths are distinguished [2] :
- Chazmoendoliths : live in crevices and rock faults
- Cryptoendoliths : live in voids in porous rocks, including in spaces formed and abandoned by euendolites
- Auendoliths : actively penetrate deep into the stones, forming tunnels corresponding in shape to their body
Habitats
Endoliths can be found in the depths of stony rocks at a depth of up to 3 km, although it is not known whether this is their limit [3] [4] . The main threat to their existence is not the pressure created at such a huge depth, but the temperature that increases as the depth deepens. Judging by hyperthermophiles , the temperature limit is 120 ° C (recently discovered strain 121 propagated at 121 ° C), therefore, the maximum depth is 4–4.5 km in the continental crust and 7 or 7.5 in the oceanic. Endolithic organisms have also been found on the surface of stones in regions with low humidity ( hypoliths ) and low temperature ( psychrophiles ), including the McMurdo Dry Valleys and permafrost in Antarctica [5] , as well as the Alps [6] and the Rockies [7] [8] .
Survival
Endoliths can survive by receiving energy from iron , potassium or sulfur (see lithotrophs ). They metabolize them exclusively from the surrounding stones or, more often, secrete the acid that dissolves them. The Ocean Drilling Program discovered microscopic traces containing DNA in basalt from the Indian , Atlantic and Pacific Oceans [9] [10] . In addition, photosynthetic endoliths were discovered.
Since water and nutrients are rare in endolithic habitats, they have a very slow reproductive cycle. According to some, earlier data, some endoliths carry out cell division once every hundred years. Most of their energy is used to repair damage caused to the cell by cosmic rays and racemization , and only a small amount of it goes to growth and reproduction. It is believed that they experienced long ice ages in this state, manifesting themselves when it was warm around [4] .
Nutrition
Most endoliths are autotrophs ; they can create the necessary organic compounds from inorganic compounds for life. Some endoliths feed on their autotrophic relatives. The microbiotopes where these various endoliths live are called the Subsurface Lithotrophic Microbial Ecosystem (PLiME) ( eng. Subsurface lithotrophic microbial ecosystem (SLiME) ) [11] . .
Notes
- ↑ J. WIERZCHOS, B. CA ´ MARA, 1 A. DE LOS RI ´ OS, AF DAVILA, IM SA´ NCHEZ ALMAZO, O. ARTIEDA, K. WIERZCHOS, B. GO´ MEZ-SILVA, C. MCKAY AND C ASCASO (2011) Microbial colonization of Ca-sulfate crusts in the hyperaridcore of the Atacama Desert: implications for the search for life on Mars. "Geobiology", Vol.9, pages 44-60]
- ↑ Stjepko Golubic, E.Imre Friedmann, and Jürgen Schneider (1981) The lithobiotic ecological niche, with special reference to microorganisms. Journal of Sedimentary Research , Vol. 51, No. 2, June: pages 475-478 unopened (unreachable link) . Date of treatment July 24, 2012. Archived December 30, 2010.
- ↑ Two miles underground - Gold mines present "ideal environment" for geologists studying subsurface microbes
- ↑ 1 2 Looking for life in all the wrong places - research on cryptoendoliths Discover , May, 1997 by Will Hively
- ↑ Microbial Diversity of Cryptoendolithic Communities from the McMurdo Dry Valleys, Antarctica
- ↑ Horath Th, Bachofen R (2009) Molecular Characterization of an Endolithic Microbial Community in Dolomite Rock in the Central Alps (Switzerland) Microb Ecol 58: 290-306 Archived July 20, 2012.
- ↑ Walker JJ, Spear JR, Pace NR (2005) Geobiology of a microbial endolithic community in the Yellowstone geothermal environment. Nature 434: 1011–1014
- ↑ Walker JJ, Pace NR (2007) Phylogenetic composition of Rocky Mountain endolithic microbial ecosystems. Appl Environ Microbiol 73: 3497-3504
- ↑ Glass Munchers Under the Sea Archived on February 20, 2013. - NASA Astrobiology Institute - Leslie Mullen
- ↑ Microbial Populations in Ocean Floor Basalt: Results from ODP Leg 187
- ↑ Frequently Requested Information about the SLiME Hypothesis Archived on September 30, 2006.
See also
- Lithotrophs
- Lithophiles