MSB: Air as an Active Bacterial Ecosystem

Fennell, Donna Elaine IOS-1022254

Air as an Active Bacterial Ecosystem

The atmosphere harbors many biological particles including bacteria and fungi. Even so, the atmosphere has long been thought to be an environment where living organisms such as bacteria are present, but biologically inactive. However, the air contains moisture, organic and inorganic particles, and chemicals that bacteria can use as food sources. This suggests that air could be an active biological ecosystem where bacteria may grow or at least consume food sources. The investigators for this project will determine whether the bacteria in the natural ambient air are growing or actively degrading chemical contaminants contained in air. The project will investigate atmospheric bacterial activity by collecting and characterizing bacteria found in the natural air. The investigators will also study ambient airborne bacteria by collecting and placing them in rotating reactors that keep the bacteria suspended in air for days while measuring their activity. Specific bacteria that are frequently detected in air will also be studied. Bacterial activity will be measured using cellular biomarkers such as ribosomes (the cell machinery that produce proteins) and adenosine triphosphate (ATP, the major energy carrier for cells). Airborne bacteria will also be fed isotopically labeled chemicals and the investigators will determine if the label is taken up by active cells, used to synthesize genomic molecules, or emitted as end products of metabolism. This project seeks to make new discoveries that reveal the potential for bacterial metabolism and/or growth in the natural air environment and to train young scientists in techniques of monitoring aerial bacteria. The work is important because it is currently unknown whether aerial bacteria transform atmospheric chemical pollutants or if they are capable of inducing biogeochemical change on a global scale. Discoveries from this project could extend our current knowledge of the biosphere by showing that the atmosphere also hosts substantial bioactivity.