Some Like It Hot, Some Like It Cold
It was long believed that no organism could survive in the desolate, cold Dry Valleys of Antarctica or in the areas of the Earth where geothermal activity is evident. Psychrophiles are organisms that live in cold environments. Living at temperatures between 1oC and 15oC, these organisms include algae, diatoms, and bacteria. Because they grow so slowly, these organisms are much more difficult to culture. In Lake Bonney, a lake permanently covered with 4 meters of ice, biologic activity is found between 12 and 20 meters. Below this suboxic region, little bacterial activity is evident.
Thermophiles are organisms that have optimal growth temperatures above 50oC. These bacteria have been isolated from hot springs, where oxygen is limited and in hydrothermal vents in deep oceans where life is dependent on organisms that use chemicals instead of sunlight for primary production.
What are the temperature ranges for the growth of common bacteria, such as Eshcerichia coli and Pseudomonas aeruginosa? Do either of these organisms withstand extremes of heat or cold? What kinds of bacteria are found in these unfriendly environments? In this activity, students will have the opportunity to witness the fragile nature of these organisms, with regard to temperature. Students will understand the role of temperature in determining what kinds of organisms are found in these unforgiving environments.
Back to: TEA Activities Page