ice
; air temperature
; Antarctica
; article
; evolution
; freshwater environment
; habitat structure
; lake
; lake ecosystem
; melting point
; microbial growth
; priority journal
; sediment
; shear stress
; stress strain relationship
; water temperature
; Antarctic Regions
; Bacteria
; Elementary Particles
; Ice
; Temperature
英文摘要:
Airborne radar has detected ≈100 lakes under the Antarctic ice cap, the largest of which is Lake Vostok. International planning is underway to search in Lake Vostok for microbial life that may have evolved in isolation from surface life for millions of years. It is thought, however, that the lakes may be hydraulically interconnected. If so, unsterile drilling would contaminate not just one but many of them. Here we report measurements of temperature vs. depth down to 2,345 m in ice at the South Pole, within 10 km from a subglacial lake seen by airborne radar profiling, We infer a temperature at the 2,810-m deep base of the South Pole ice and at the lake of -9°C, which is 7°C below the pressure-induced melting temperature of freshwater ice. To produce the strong radar signal, the frozen lake must consist of a mix of sediment and ice in a flat bed, formed before permanent Antarctic glaciation. It may, like Siberian and Antarctic permafrost, be rich in microbial life. Because of its hydraulic isolation, proximity to South Pole Station infrastructure, and analog to a Martian polar cap, it is an ideal place to test a sterile drill before risking contamination of Lake Vostok. From the semiempirical expression for strain rate vs. shear stress, we estimate shear vs. depth and show that the IceCube neutrino observatory will be able to map the three-dimensional ice-flow field within a larger volume (0.5 km3) and at lower temperatures (-20°C to -35°C) than has heretofore been possible.
Price, P.B., Physics Department, University of California, Berkeley, CA 94720, United States; Nagornov, O.V., Moscow Engineering Physics Institute, Moscow 115409, Russian Federation; Bay, R., Physics Department, University of California, Berkeley, CA 94720, United States; Chirkin, D., Physics Department, University of California, Berkeley, CA 94720, United States; He, Y., Rosetta Inpharmatics, 12040 115th Avenue, Kirkland, WA 98034-4399, United States; Miocinovic, P., Physics Department, University of California, Berkeley, CA 94720, United States; Richards, A., Indigo Systems Corporation, 5385 Hollister Avenue, No. 103, Santa Barbara, CA 93111, United States; Woschnagg, K., Physics Department, University of California, Berkeley, CA 94720, United States; Koci, B., Space Sciences and Engineering Laboratory, University of Wisconsin, Madison, WI 53706, United States; Zagorodnov, V., Byrd Polar Research Center, Ohio State University, Columbus, OH 43210, United States
Recommended Citation:
Price P.B.,Nagornov O.V.,Bay R.,et al. Temperature profile for glacial ice at the South Pole: Implications for life in a nearby subglacial lake[J]. Proceedings of the National Academy of Sciences of the United States of America,2002-01-01,99(12)