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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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All life needs nitrogen, but most organisms can use only nitrogen that has been “fixed,” or transformed into a biologically useful form by microbes. A dearth of fixed nitrogen has even been invoked as an explanation for Earth’s “Boring Billion,” a 1-billion-year period in the Proterozoic when the expansion and evolution of life seem to have ground to a halt. A new study shows purple sulfur bacteria in Proterozoic-analogue Lake Cadagno, Switzerland, can fix nitrogen at rates comparable to the low end achieved by cyanobacteria. Jennifer Glass, associate professor in the School of Earth and Atmospheric Sciences who was not involved in the study, comments on the research.
