Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
215
result(s) for
"McKay, Chris"
Sort by:
What Is Life—and How Do We Search for It in Other Worlds?
[...]the Sun and the outer Solar System have more than 10,000 times the carbon content of the bulk of Earth (McKay 1991). On Jupiter's moon Europa, the cracks and icebergs on the surface of the ice indicate water beneath the ice, but not necessarily at the present time. Organic material of biological origin will eventually lose its distinctive pattern when exposed to heat and other types of radiation, (examples of this include the thermal racemization of amino acids), but at the low temperatures in the Martian permafrost, calculations suggest that there has been no thermal alteration (Kanavarioti and Mancinelli 1990).
Journal Article
Characterization of the microbial diversity in a permafrost sample from the Canadian high Arctic using culture-dependent and culture-independent methods
A combination of culture-dependent and culture-independent methodologies (Bacteria and Archaea 16S rRNA gene clone library analyses) was used to determine the microbial diversity present within a geographically distinct high Arctic permafrost sample. Culturable Bacteria isolates, identified by 16S rRNA gene sequencing, belonged to the phyla Firmicutes, Actinobacteria and Proteobacteria with spore-forming Firmicutes being the most abundant; the majority of the isolates (19/23) were psychrotolerant, some (11/23) were halotolerant, and three isolates grew at -5°C. A Bacteria 16S rRNA gene library containing 101 clones was composed of 42 phylotypes related to diverse phylogenetic groups including the Actinobacteria, Proteobacteria, Firmicutes, Cytophaga - Flavobacteria - Bacteroides, Planctomyces and Gemmatimonadetes; the bacterial 16S rRNA gene phylotypes were dominated by Actinobacteria- and Proteobacteria-related sequences. An Archaea 16S rRNA gene clone library containing 56 clones was made up of 11 phylotypes and contained sequences related to both of the major Archaea domains (Euryarchaeota and Crenarchaeota); the majority of sequences in the Archaea library were related to halophilic Archaea. Characterization of the microbial diversity existing within permafrost environments is important as it will lead to a better understanding of how microorganisms function and survive in such extreme cryoenvironments.
Journal Article
Is there anybody out there?
Davies gives a clear and up-to-date summary of the search for life in all its forms ... from scouring Earth for microscopic aliens, through the search for signs of life on Mars and on to possibilities of life and intelligence on planets beyond the Solar System. Because these questions must be answered if we are to understand our place in the Universe, the search must go on.
Journal Article
Perennial spring occurrence in the Expedition Fiord area of western Axel Heiberg Island, Canadian High Arctic
This paper documents perennial spring activity at Expedition Fiord on western Axel Heiberg Island in the Canadian High Arctic. Two groups of mineralized springs occur near the McGill University Axel Heiberg Research Station located at 79°26'N, 90°46'W. The first is at Gypsum Hill, 3 km from the terminus of the White and Thompson glaciers, and the second site is at Colour Peak, approximately 10 km downvalley near the head of Expedition Fiord. Each spring group consists of 20-40 vents spread over several hundred square metres. The highly mineralized nature of the discharge causes a freezing-point depression of 7-10°C and produces a range of precipitates and travertine deposits. Year-round water temperature and discharge rate measurements have been obtained, demonstrating perennial activity at these sites. Results indicate that temperatures range from -4.0 to 6.6°C among the individual sources; however, water temperatures at the various outlets remain constant throughout the year despite a mean annual air temperature of -15°C. Although discharge from any one outlet is low (<0.5 to 2.0 L/s), the total discharge is substantial, each year producing several seasonal frost mounds and an icing 180 000 - 300 000 m
2
at the Gypsum Hill site.
Journal Article