Seasonal Variations in Microbial Phylogeny and the Atmospheric Pools of Primary Biopolymers in Temperate Sub-Alpine Settings, Colorado USA

ALINA M. HANDOREAN (1), Kevin M. McCabe (1), Alison Ling (1) and Mark T. Hernandez (1)

(1) University of Colorado at Boulder

     Abstract Number: 728
     Last modified: May 14, 2010

Abstract

While generally considered oligotrophic, the atmosphere carries biochemical hallmarks of life – both in primary and weathered forms. The contribution of the most primary biopolymers — DNA, lipids, carbohydrates and proteins — to the pool of atmospheric organic carbon remains relatively unknown, as is their potential to participate in secondary aerosol formation in different environments.
We report here, the first phylogenetic characterization of atmospheric DNA pools juxtaposed to the carbohydrate, proteins and phospholipids content of airborne particulate matter in samples from the Manitou Experimental Forest (Colorado, USA). Size segregated PM10, retained on 90 mm quartz filters were extracted with chloroform-isopropanol mixtures, and airborne genomic DNA was precipitated with ammonium acetate using glycogen as a carrier. DNA was amplified by polymerase chain reaction using universal ribosomal subunit primers for bacteria and fungi. These PCR products were cloned, sequenced and compared to the NCBI sequence database for genus level identification. We report the diversity of the microbiological populations present in air during summer 2008 to be remarkably low, exhibiting near daily variation, and dominated by only a few genera. In a source-tracking paradigm, we correlated the presence of specific genera with a suite of meteorological data including air temperature, wind speed and direction, humidity, and precipitation collected onsite by National Center for Atmospheric Research, which oversees the Manitou Experimental Forest.
Aerosol biodiversity was compared to primary pools of water-soluble carbohydrate, proteins and solvent-extracted phospholipids from the same filters. The mass and OC fraction of these biopolymers is presented as an index of vegetative materials and microbial biomass (PMBIO) comprising total bioaerosol loads and correlated to the types of microorganisms present in this unique and pristine setting.