097: The Cool World of Glacial Microbiology with Christine Foreman

Christine Foreman explains how microbes can survive and grow on glaciers, and what we can learn from microbes in glacier ice cores.

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Julie’s Biggest Takeaways

Liquid inclusions between ice crystals create a vein-like network that allow microbes to survive between the ice crystals.

Microbes living in glaciers have to adapt to a number of extreme environments: low water, low nutrients, extreme cold, and 6 months each of full sun or complete darkness mean there are many adaptive requirements to live in glaciers.

Air bubbles trapped in ice cores provide data on the atmosphere 40,000 or 100,000 years ago. Using very old samples like these can inform scientists about the precipitation, temperature, and major cataclysmic events that occured at those time periods.

Because so many researchers share ice core samples, a research group like Foreman’s will often get a very small sample, as low as 7 ml, for a particular time period. Given that there are only 100 to 10,000 cells per ml, that is not a lot of sample to work with!

Aggregation of life, including microbial biofilms, changes the absorption of solar radiation. A clear, white surface radiates back as much as 90% of the solar radiation, but as aggregates form, they allow more of the solar radiation to be trapped. This in turn can increase microbial metabolic activity and allow even more microbial growth, leading to a feedback loop that increases absorption of solar energy and loss of glacial surfaces.

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