The Biology of Coastal Fog

Bacteria suspended in the atmosphere, or microbial aerosols, affect climate through serving as ice, cloud and fog nucleators, and have the metabolic potential to alter atmospheric chemistry. Microbial aerosols are known to be diverse in identity and biogeochemical capacity, and can be transported between seemingly isolated biomes (e.g. ocean to land, desert to ocean). On the coast of Maine, we found that fog presence increased microbial aerosol viability, and the deposition of viable microbial aerosols increased by three orders of magnitude. Molecular identification of depositing microbes revealed a diverse community of predominantly marine organisms, confirming the atmospheric transfer of viable bacteria from the ocean surface to the coastal environment. Important environmental controls on this transfer include onshore wind speeds and tidal movement. Implications for this transfer include bi-directional atmospheric feedbacks between terrestrial and coastal ocean systems and the potential for water quality to affect air quality at coastal sites.