Measuring biological dust in the wind
In the popular children’s story “Horton Hears a Who!” author Dr. Seuss tells of a gentle and protective elephant who stumbles upon a speck of dust that harbors a community of microscopic creatures called the Whos living the equally tiny town of Whoville. Throughout their journey together, Horton argues for the existence of the Whos traveling around in the air on a dust speck, while doubters dispute the finding. Ultimately, through observation, evidence for the organisms emerges, but regardless of the outcome, this speck altered a world greater than its own. While this tale is a work of fiction, climate and atmospheric scientists have considered a real-life Whoville scenario — biological particles and inorganic material riding around in the atmosphere affecting the climate. Previous research has shown that some aerosols are very good at nucleating ice, which could form clouds in the troposphere. But due to complex atmospheric chemistries and a lack...