DISCLAIMER: This article is being kept online for historical purposes. Though accurate at last review, it is no longer being updated. The page may contain broken links or outdated information.
Borgonie, Gaetan Nematology Section, Department of Biology, Ghent University, Ghent, Belgium.
- Habitat and ecology
- Additional observations
- Related Primary Literature
- Additional Reading
The deep subsurface biosphere, extending more than 3 km (1.86 mi) under the Earth's surface, comprises a significant fraction of the global planetary biosphere. Limitations imposed by temperature, energy, oxygen, and space led to the conviction that the deep subsurface was populated exclusively by bacteria and viruses with a total biomass equaling that of the surface. However, no multicellular organisms were believed to be able to survive at these depths. Although many lower invertebrate phyla have a reputation for being able to survive in harsh conditions, the phylum Nematoda (also termed Nemata, comprising the roundworms) is second to none. (Roundworms are not to be confused with earthworms, which belong to the phylum Annelida.) Nematodes have been recovered from the seafloor of deep oceans, hot springs, and acidic seeps (pH 0), and some species recover easily from deep freezing or decades of desiccation. However, the most impressive example of stress resistance in nematodes was demonstrated by the survival of the species Caenorhabditis elegans during the 2003 breakup of the space shuttle Columbia upon reentry, and the subsequent free fall and impact of the biological container in which the species was contained. In addition to the ability of nematodes to undergo anabiosis (a state of suspended animation induced by desiccation and reversed by the addition of moisture) for extended periods, these organisms continue to metabolize aerobically in hypoxic (oxygen-deficient) environments where the partial pressure of oxygen (O2) is only 0.4 kPa (2% of the atmospheric value). Therefore, nematodes were regarded as prime candidates to look for in the deep subsurface because they are one of the most successful metazoan phyla on the surface with respect to their abundances, distribution, and physiological tolerances.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 46 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information