Biogeochemistry, temperature, and precipitation combine to form the abiotic template constraining ecological abundance and function. The importance of biogeochemistry thus far rests largely on studies of carbon, nitrogen, and phosphorus. However, ca. twenty five elements are required to build an organism; their biogeochemistry is nonrandomly distributed at multiple spatial scales; and the shortfall of any can cause pathology in organisms, slow growth rates of populations, and reduce the work they do in ecosystems. Micronutrients like sodium, calcium, zinc, and copper thus have enormous potential to inform physiological, community, and geographical ecology. We highlight the growing body of work revealing how micronutrients, particularly sodium, catalyze ecological interactions, constrain the abundances and activity of herbivores and detritivores, and shape food web structure. We show that the way populations and communities behave often tracks the biogeography of biogeochemistry. We highlight a variety of ways that understanding the distribution of micronutrients may answer old questions and pose new opportunities for ecology.