| Summary: | The goal of this proposal is to explore the microbiology of frost flowers -- delicate ice crystal structures with high brine content that form on the surface of new sea ice in winter -- through controlled experiments in the field (near Barrow, Alaska) and in the laboratory. The working hypothesis is that frost flowers, as they wick brine from sea ice during growth, serve as upward vectors for microbes and viruses, concentrating them in structures where some microbial and viral activity may proceed prior to aerial dispersal or following collapse under snow. In the field, experimental plots will enable time-course sampling of frost flowers and environs to examine these ideas. Laboratory work will track 1-um fluorescent beads (as passive bacterial mimics), live bacteria, and a coldstable virus, singly and in combination, from source seawater into frost flowers. Further tests will address selective transport or ice retention due to exopolymer coatings. Microbial activity in frost flower brines will be tested both in situ and in the laboratory using the respiratory stain CTC, while selective transport, ice-retention or virally mediated loss of specific phylotypes (of Bacteria and Archaea) will be evaluated using a DNA fingerprinting approach (T-RFLP). Outreach and educational activities associated with proposed research include coordinating fieldwork with the NASA JPL project on the Astrobiology of Icy Worlds, involving residents of Barrow in fieldwork, participating in Barrow K-12 classroom activities, and training of undergraduate and graduate students.
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