Geomicrobiological Experiments in Altered Gravity

Two experiments with Sphingomonas desiccabilis are being carried out in order to investigate how reduced- and hyper-gravity affect biofilm formation and the biological leaching of elements from rock substrates. One experiment will take place on-board the ISS at Martian and micro-gravity, using new hardware designed specifically for biomining studies in space. The other experiment has been conducted at 10 x g in a geotechnical centrifuge at the university of Dundee, and is the first experiment to grow and study biofilms in a hyper-gravity environment.

After exposure, the methods used to study the samples from both experiments are laser scanning confocal microscopy to image the biofilms, and inductively coupled mass spectrometry to measure the differences in elemental release rates. Additional analysis in the hyper-gravity experiment consists of crystal violet assays to quantify the differences in biomass, and colony forming unit counts backed up with optical density to determine planktonic growth. Results so far show that biofilms will form in conditions with higher than terrestrial gravity environments, and that there are differences in the biofilm structure and biomass.