Temperature recorded in DNA and soft-tissue biomass: Implications for the deep-sea biosphere

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This is potentially transformative research that focuses on whether the oxygen isotope ratios in phosphate in DNA record the temperature at which organisms grow. Its purpose is to explore the environmental conditions and temperature optima for life in ancient and modern extreme environments. The approach uses controlled laboratory experiments in which microbes and a limited number of model macrofauna, such as zebra fish, are cultured/grown over a wide range of temperatures. Microbial studies will be done on pure cultures of species with known growth temperature ranges. The impacts of growth rate, nutrient limitation, pH, and phosphate uptake rate on the temperature dependence of the oxygen isotope ratio of phosphate in DNA will also be examined. In addition the work will test the robustness of the DNA and biomass isotope temperature record by analyzing natural samples of micro-and macro-organisms collected from thermally extreme environments such as hot springs and deep-sea hydrothermal vents. Because DNA is a fundamental unit of all life, this work will provide a robust understanding of its temperature-recording properties which could have far-reaching implications for determining the upper temperature limit for life and will shed light on environments in which life can exist on Earth and other planets. Broader impacts of the work are significant and include complete integration of research and education from the high school to the postdoctoral level, support of students, and support of two researchers who are from groups under-represented in the sciences.