ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Tab. 3: Substrate pH values of crypthoendolithic microbial communities
    PANGAEA
    In:  Supplement to: Friedmann, E Imre; Hua, Maosen; Ocampo-Friedmann, Roseli (1988): 3.6 Cryptoendolithic lichen and cyanobacterial communities of the Ross Desert, Antarctica. Polarforschung, 58(2/3), 251-259, hdl:10013/epic.29621.d001
    Details
    Publication Date: 2023-05-12
    Description: Cryploendolithic microbial communities in the Ross Desert (McMurdo Dry Valleys) are characterized on the basis of photosymlictic microorganisms and fungi. Two eukaryotic communities (the lichen-dominated and Hemichloris communities) and three cyanobacterial communities (the red Gloeocapsa, Hormathonema-Gloeocapsa and Chroococcidiopsis communities) are described. Eleven coccoid. ohne pleurocapsoid, and five filamentous cyanobacteria occurring in these communities are characterized and illustrated. The moisture grade of the rock substrate seems to affect pH. Formation of primary iron stain, and the distribution of microbial communities.
    Keywords: Area/locality; Battleship Promontory, Alatna Valley, Victoria Land, Antarctica; BP-ant; Event label; HAND; Linnaeus Terrace, Asgard Range, southern Victoria Land; Location type; LT-ant; pH; Sample code/label; Sampling by hand
    Type: Dataset
    Format: text/tab-separated-values, 64 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 2
    facet.materialart.
    Unknown
    Table 3: Reproductive viability of Hemichloris antarctica after cycles of cooling und warming (1988)
    PANGAEA
    In:  Supplement to: Meyer, M A; Huang, G-H; Morris, G J; Friedmann, E Imre (1988): 2.2 The effect of low temperatures on Antarctic endolithic green algae. Polarforschung, 58(2/3), 113-119, hdl:10013/epic.29606.d001
    Details
    Publication Date: 2023-07-10
    Description: Laboratory experiments show that undercooling to about -5°C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5°C and -5°C or -10°C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50°C. l4CO2 incorporation after freezing to -20°C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.
    Keywords: Age; Cycles; Range; Standard deviation; Viability
    Type: Dataset
    Format: text/tab-separated-values, 112 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 3
    Electronic Resource
    Electronic Resource
    The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Light in the photosynthetically active region (1988)
    Springer
    Microbial ecology 16 (1988), S. 271-289 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The vertical zonation of the Antarctic cryptoendolithic community appears to form in response to the light regime in the habitat. However, because of the structure of the habitat, the light regime is difficult to study directly. Therefore, a mathematical model of the light regime was constructed, which was used to estimate the total photon flux in different zones of the community. Maximum fluxes range from about 150μm photons m−2 s−1 at the upper boundary of the community to about 0.1μm photons m−2 s−1. Estimates of the annual productivity in the community indicate that the lowest zone of the community is light limited, with the maximal annual carbon uptake equivalent to less than the carbon content of one algal (Hemichloris) cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02011700
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Mathematical models of the thermal regime (1988)
    Springer
    Microbial ecology 16 (1988), S. 253-270 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microbial activity in the Antarctic cryptoendolithic habitat is regulated primarily by temperature. Previous field studies have provided some information on the thermal regime in this habitat, but this type of information is limited by the remoteness of the site and the harsh climatic conditions. Therefore, a mathematical model of the endolithic thermal regime was constructed to augment the field data. This model enabled the parameters affecting the horizontal and altitudinal distribution of the community to be examined. The model predicts that colonization should be possible on surfaces with zenith angle less than 15°. At greater zenith angles, colonization should be restricted to surfaces with azimuth angles less than 135° or greater than 225°. The upper elevational limit of the community should be less than 2,500 m. The thermal regime probably does not influence the zonation of the community within a rock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02011699
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Water relations and photosynthesis in the cryptoendolithic microbial habitat of hot and cold deserts (1990)
    Springer
    Microbial ecology 19 (1990), S. 111-118 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two cryptoendolithic microbial communities, lichens in the Ross Desert of Antarctica and cyanobacteria in the Negev Desert, inhabit porous sandstone rocks of similar physical structure. Both rock types adsorb water vapor by physical mechanisms unrelated to biological processes. Yet the two microbial communities respond differently to water stress: cryp-toendolithic lichens begin to photosynthesize at a matric water potential of −46.4 megaPascals (MPa) [70% relative humidity (RH) at 8°C], resembling thallose desert lichens. Cryptoendolithic cyanobacteria, like other prokaryotes, photosynthesize only at very high matric water potentials [〉 −6.9 MPa, 90% RH at 20°C].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02015057
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Nitrogen economy of endolithic microbial communities in hot and cold deserts (1980)
    Springer
    Microbial ecology 6 (1980), S. 95-108 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The source of combined nitrogen in endolithic microbial communities was studied in samples from desert localities in North and South America, the Middle East, South Africa, and Antarctica. Nitrogen fixation (acetylene reduction) seems to occur only exceptionally. Evidence suggests that, in general, the nitrogen source for endolithic microorganisms in deserts is abiotically fixed nitrogen produced by atmospheric electric discharges (lightning or aurorae), conveyed to the rock by atmospheric precipitation. Nitrogen is apparently not a limiting factor in these low-productivity communities. An incomplete nitrogen cycle seems to be present which includes the following pathways: supply of nitrates and ammonia from the atmosphere; decomposition of organic matter to ammonia; reassimilation of ammonia; ammonia volatilization; loss of organic matter through weathering (only in certain Antarctic rocks); biological nitrogen fixation (exceptional).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010548
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effects of water stress on cryptoendolithic cyanobacteria from hot desert rocks (1981)
    Springer
    Archives of microbiology 130 (1981), S. 267-271 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Chroococcidiopsis ; Chroococcus ; Water stress ; Photosynthesis ; Endolithic ; Matric ; Osmotic ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four strains of Chroococcidiopsis and one Chroococcus, all isolated from extreme arid desert rocks, and one marine Chroococcus, were subjected to water stress using both matric and osmotic control methods. For all Chroococcidiopsis strains, photosynthetic rates decreased with decreasing water potential. After 24h preincubation the decrease was linear but after 72h there was a sharp drop below-3400 kPa (a w≏0.976). In contrast, the two Chroococcus strains showed optimum photosynthesis between-3000 and-4000 KPa. It appears, therefore, that Chroococcidiopsis in deserts may have a different survival strategy in response to aridity than Chroococcus (rare in deserts). Absolute rates of 14CO2 uptake were higher in matric than in osmotic control systems. It is suggested that, in a matric experimental system, the water status is more representative of the natural conditions in arid environments. The consistent differences between different strains in their response to water stress suggest that this character in Cyanobacteria may be of taxonomic significance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425938
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Endolithic microbial life in hot and cold deserts (1980)
    Springer
    Origins of life and evolution of the biospheres 10 (1980), S. 223-235 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Endolithic microorganisms (those living inside rocks) occur in hot and cold deserts and exist under extreme environmental conditions. These conditions are discussed on a comparative basis. Quantitative estimates of biomass are comparable in hot and cold deserts. Despite the obvious differences between the hot and cold desert environment, survival strategies show some common features. These endolithic organisms are able to ‘switch’ rapidly their metabolic activities on an off in response to changes in the environment. Conditions in hot deserts impose a more severe environmental stress on the organisms than in the cold Antarctic desert. This is reflected in the composition of the microbial flora which in hot desert rocks consist entirely of prokaryotic microorganisms, while under cold desert conditions eukaryotes predominate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00928400
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The cryptoendolithic microbial environment in the Antarctic cold desert: Temperature variations in nature (1985)
    Springer
    Polar biology 4 (1985), S. 19-25 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the Antarctic cold desert, cryptoendolithic microorganisms live under the surface of porous sandstone rocks. During the austral summer, the environment of the near-surface rock layers colonized by organisms is characterized by two kinds of temperature oscillations, both occurring across the freezing point. Low-frequency (diurnal) and large-amplitude (up to about 20°C) oscillations on the sunlit surface of rocks result in a daily freeze-thaw cycle. This is a result of the diurnal changes in the sun altitude and angle with respect to the rock surface. The biological effect of this oscillation is the regulation of the onset and cessation of metabolic activity. The high-frequency (few minutes) oscillations occur only under certain weather conditions (sunny days with light winds) and are superimposed on the low-frequency oscillations. They are caused by the cooling effect of wind gusts on rock surfaces that are much warmer than ambient air temperatures. High-frequency oscillations result in a rapid freeze-thaw cycle on the surface, which, however, does not reach the microbial zone. These high-frequency freeze-thaw oscillations are probably the cause of the abiotic nature of the rock surface. Both oscillations seem to have an effect on rock weathering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286813
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Satellite-transmitted continuous nanoclimate data, 1984 to 1986 (1987)
    Springer
    Polar biology 7 (1987), S. 273-287 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A satellite mediated station for monitoring nanoclimate (climate in the millimeter range) data, suitable for use in polar regions is described. The station, located in the Ross desert of Antarctica, has been in operation for more than 3 years, measuring rock temperatures, air temperature, light, snow, wind, and moisture. The data indicate that biological activity in the cryptoendolithic microbial ecosystem is limited to the period from mid November to mid February. The total number of hours of biological activity, based on assumptions of the minimum light, temperature and moisture requirements of the community, is less than 1000 h/year. The time above 0°C, representing more nearly optimal conditions, is between 50 and 550 h/year, depending on the orientation of the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00443945
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...