Elevated bacterial abundance and exopolymers in saline frost flowers and implications for atmospheric chemistry and microbial dispersal

Frost flowers (FF) have been studied for their potential influence on ice-surface reflectivity and roles in atmospheric chemistry, but not as microbial habitats. We examined FF grown in a freezer laboratory from a bacteria-containing saline solution and FF formed naturally in the coastal (April) and central Arctic Ocean (September). All FF contained bacteria (up to 3.46 x 10(6) ml(-1) in natural FF) with densities 3-6-fold higher than in underlying ice. Bacterial abundance correlated strongly with salinity in FF (p values <= 0.001), a correlation that held for all components of the surface-ice environment (p < 0.0001, coastal samples). Concentrations of extracellular polysaccharides were also elevated in FF and brine skim relative to underlying ice (up to 74-fold higher). Here we consider implications of finding microbes and exopolymers within the chemically reactive surface-ice environment to the photolytic production of oxidants and long-range transport of potential ice-nucleating particles in the atmosphere. Citation: Bowman, J. S., and J. W. Deming (2010), Elevated bacterial abundance and exopolymers in saline frost flowers and implications for atmospheric chemistry and microbial dispersal, Geophys. Res. Lett., 37, L13501, doi: 10.1029/2010GL043020.