Environmental Engineering Reference
In-Depth Information
SUMMARY
1. Organisms have special adaptations to extreme habitats, allowing
them to utilize a tremendous range of extremes. Bacteria and Archaea
dominate in the most extreme habitats.
2. Physiological adaptations to high temperature include lipids with
higher melting points and stabilizing features of proteins and nucleic
acids.
3. Organisms in high-salinity habitats need to regulate osmotic pressure,
as do those that can withstand drying.
4. Diversity decreases as habitats become more extreme.
5. Hot springs have served as attractive communities for study because
of their stable nature, low diversity, and the adaptations of the
organisms that are able to live in near-boiling water.
6. Temporary pools are colonized quickly by organisms that are able to
withstand desiccation or those that can move in from nearby sources.
7. Active microbial communities are found in regions of melted water in
ice and snow, in ultraoligotrophic habitats, and in groundwater up to
1000 m below the earth's surface.
8. The air-water interface (neustonic habitat) is an extreme environment.
High surface tension and high irradiance are characteristics of this
habitat.
QUESTIONS FOR THOUGHT
1. Can extreme habitats serve as models for early life on Earth or
possible life on other planets?
2. Should efforts be made to conserve the biodiversity of unusual
habitats such as hot springs?
3. Should companies be able to patent and take full profit from gene
sequences taken from organisms collected in national parks without
remuneration to the government?
4. Are “extreme” habitats really extreme for organisms adapted to live
in them?
5. Why can the depth of a saline lake be highly variable from year to
year and from decade to decade, and how may global climate change
influence such lakes?
6. Why might saltworks that precipitate brines be interested in the
microbiology of saline waters?
7. How much (%) is the estimated thickness of the biosphere increased
by the understanding that organisms can inhabit up to 500-m depth?
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