Exploring Earth's Atmospheric Biology using a Platform-Extensible Sampling Payload

The interactions between Earth's atmosphere and its biosphere, or aerobiology, remain a significant unknown. What few studies have been done conclusively show that Earth's atmosphere has a rich and dynamic microbial presence[Bowers et al., 2010]; that microbes suspended in air survive over long times (1-2 weeks)[Smith et al., 2010] and travel great distances (>5000 km)[Kellogg and Griffin, 2006]; that some airborne bacteria actively nucleate ice crystals, affecting meteorology[Delort et al., 2010]; and that the presence of microbes in the atmosphere has other planetary-scale effects[Delort et al., 2010]. Basic questions, however, such as the number of microbes present, their activity level and state, the different species present and their variance over time and space, remain largely unquantified. Compounding the significant physical and environmental challenges of reliable aerobiological sampling, collection and analysis of biological samples at altitudes above ~10-20 km has traditionally used ad hoc instrumentation and techniques, yielding primarily qualitative analytical results that lack a common basis for comparison[Bowers et al., 2010]. There is a strong need for broad-basis, repeatable, reliably comparable data about aerobiological basics. We describe here a high-altitude environmental and biological sampling project designed specifically to address these issues. The goal is a robust, reliable, re-usable sampling system, with open reproducibility and adaptability for multiple low-cost flight platforms (including ground-tethered systems, high-altitude balloons, and suborbital sounding rockets); by establishing a common modular payload structure for high-altitude sampling with appeal to a broad user base, we hope to encourage widespread collection of comparable aerobiological data. We are on our third prototype iteration, with demonstrated function of two sample capture modules, a support backbone (tracking, data logging, event response, etc.), a simple ground station, and a partially complete environmental sensing module. Successful deployments include ground sampling (Dec. 2011-ongoing, with biological and environmental data correlation) and instrument verification suborbital launches (Apr. 2012). Intensive calibration and characterization of the sampling modules is ongoing. Full three-module balloon flights are scheduled for Sep. 2012. References: Bowers, R. et al. (2010), Spatial variability in airborne bacterial communities across land-use types and their relationship to the bacterial communities of potential source environments, The ISME Journal (2010), 1-12, doi:doi:10.1038/ismej.2010.167. Delort, A. M. et al. (2010), A short overview of the microbial population in clouds: Potential roles in atmospheric chemistry and nucleation processes, Atmospheric Research, 98249-260, doi:10.1016/j.atmosres.2010.07.004. Kellogg, C. A., and Griffin, D. W. (2006), Aerobiology and the global transport of desert dust, Trends in Ecology and Evolution, 21(11), 638-644, doi:10.1016/j.tree.2006.07.004. Smith, D. J. et al. (2010), Stratospheric microbiology at 20 km over the Pacific Ocean, Aerobiologia, 26(1), 35-46, doi:10.1007/s10453-009-9141-7.