In nature, the rarest ingredient can be the one that holds everything together. In a new article published in Trends in Ecology Evolution, Dr. Erika C. Freeman of the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin argues that a handful of scarce molecules can shape ent ire living communities, far out of proportion to how little is present. These are what ecologists call "keystone molecules." ...read more read less