What is it like to dive beneath 6 meters of ice?  If you could travel back in time to the dawn of life, how would the nascent microbial ecosystems appear? In many ways, diving into the perennially ice-covered lakes of the Antarctic is like traveling back in time on our own planet - to an era when plants and animals that are so common to us today did not yet exist - microbes ruled the world! Some of these microbes had discovered how to harness sunlight as an energy source - a biochemical process we call photosynthesis. A byproduct of photosynthesis is oxygen and the vast communities of microorganisms present on early Earth gradually helped to transform the atmosphere into what we have today - an oxygen/nitrogen rich mix.