In the world’s oceans, microbes capture solar energy, catalyze key biogeochemical transformations of important elements, produce and consume greenhouse gases, and comprise the base of the marine food web. Microbial ecologists working within Sonya Dyhrman’s laboratory at Lamont-Doherty Earth Observatory strive to understand the oceans’ ecosystem processes by studying a multitude of creatures, most too small for the human eye to see. These are the tiny microbes called phytoplankton that live beneath the ocean’s surface, taking in carbon dioxide, sunlight and nutrients to produce oxygen. That oxygen is essential to human survival.