Determining Microbial Assemblages in Snow Using Different G rowth Media Ama Agyekum

1. Determining Microbial Assemblages in Snow Using Different Growth Media Ama Agyekum Department of Biological Sciences, York College of Pennsylvania Plates showing microbial diversity Mold and yeast on R2A plates Material and Methods • Introduction • Studies have been done on the microbial diversity of thermophiles from extremely hot environments but only a handful have focused on the microbial diversity of microbes that live in extremely cold environments (Jungblut et al 2012). • Molecular methods of soil and water microbial populations have been done using genetic sequencing of small subunits (SSU) ribosomal RNA(Crump et al 2012 , Imazaki and Kobori 2010) • Microbial population analyses of snow taken from two different lakes in Canada revealed a diverse collection of taxa with a total of 25 bacterial operational taxonomic units (OTUs) and 23 eukaryotic OTUs (Harding et al 2012). • Bacterial and eukaryotic communities, taken from snow and ice sheet covers of high mountain top lakes, were morphologically diverse (Felip et al 1995). • In determining the viability of bacteria, the spread-plate procedure has been used to isolate and recover bacteria from environmental samples because it is an easy and reliable technique (Imazaki and Kobori 2010). • Molecular methods for measuring diversity do not measure viability. Also, since few microbes can be cultured, determining the diversity of viable environmental microbes is challenging. • Viability and diversity can be determined by counting microbes grown on various enriched and selective medias. Table. 1. The grams of nutrients in 1 liter of the 2 different media. R2A agar has a wide variety of nutrient but the total amount per Liter is half as much as the Nutrient agar. • R2A results • Mold was present in all 5 sites • Bacteria present at sites 1, 2, 4,5 • Yeast present in site 1 and 5 • Nutrient agar results • Bacteria and yeast was present in sites 1, 2 and 5 • Mold was only present in site 4 • Objectives • To investigate the diversity and likely source environments of microbes in the snow in York College of Pennsylvania Campus. • To access the ability of different media to culture microorganisms Results • Conclusion • There was more microbial diversity on R2A, which was expected because of nutrient content of agar. • Site 5 had the highest microbial counts on both plates so location (closest to city) might influence concentration. • Yeast counts were low which was probably due to competition for nutrients (plates overgrown by fungus and/or bacteria). Literature Cited Felip, M., Sattler B., Psenner, R., and Catalan, J. 1995.Highly Active Microbial Communities in the Ice and Snow Cover of High Mountain Lakes. Applied and Environmental Microbiology 61: 2394–2401 Harding, T., Jungblut, A. D., Lovejoy, C. and Warwick , V. F. 2011. Microbes in High Arctic Snow and Implications for the Cold Biosphere. Available from: http://aem.asm.org/content/77/10/3234.full. Accessed 2013 September 12 Imazaki, I., and Kobori, Y. (2010). Improving the culturability of freshwater bacteria using FW70, a low-nutrient solid medium amended with sodium pyruvate. Canadian Journal Of Microbiology 56: 333-341. Jungblut, A. D., Lovejoy, C. and Vincent, W. F. 2010. Global distribution of cyanobacterial ecotypes in the cold biosphere. The ISME Journal 4:191–202. Morris, C. E et al. 2008. The life history of the plant pathogen Pseudomonas syringae is linked to the water cycle. Available from:http://www.nature.com/ismej/journal/v2/n3/full/ismej2007113a.html. Accessed 2013 September 13. Figure 1. Pictures of bacteria (top right and left), mold (bottom left) and yeast (bottom right). Pictures were taken with Samsung Illusion camera phone