Yayanos, A. A.. University of California San Diego, Scripps Institution of Oceanography, 619 534-7313
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THE STRESSES AND STRAINS ON LIFE IN THE DEEP SEA: THE INFLUENCE OF PRESSURE, TEMPERATURE, NUTRITION AND RADIATION ON DEEP-SEA BACTERIA
Bacteria of the cold deep sea are piezophilic. The concept of piezophily is an outcome from the study of bacterial growth physiology with PTk-diagrams where P is the pressure, T the temperature and k the exponential growth rate constant. Each bacterial isolate studied is thus described by an infinite number of PTk surfaces, each for a given set of nutrient conditions. A PTk surface when growth is under copiotrophic conditions shows a single maximum value of k which occurs at non-habitat pressures and temperatures. When growth is under nutrient limited conditions, the PTk diagram of bacterial isolate PE36 is modified by the carbon source utilized. Furthermore, comparisons with PTk diagrams of bacteria from habitats of different T and P show that pressure adaptation is not a single parameter phenomenon but one that is modulated by T as well as by nutrition. Comparisons of PTk diagrams of hyperthermophiles with those of hyperpiezopsychrophiles show that there are likely potential PT habitats which are not found on Earth. Evidence so far supports the hypothesis that bacteria of the dark deep-sea are ultra-sensitive to UV light and unremarkably sensitive to ionizing radiation. Deep-sea bacteria are windows to the past, the future, and other worlds.
Day: Tuesday, Feb. 2
Time: 08:45 - 09:00am
Location: Sweeney Center