Maga Gei is an ecosystem ecologist with expertise in biogeochemistry of tropical forests and the legume-rhizobia symbiosis. Gei completed her Ph.D. in Ecology at the University of Minnesota in the Spring of 2014. She also holds a BS in Biology and a Licenciate (specialization) in Botany from the University of Costa Rica.

In 2010, Gei was awarded a L'Oréal-UNESCO Fellowship for Young Women in Life Sciences to conduct dissertation research in northwestern Costa Rica's Área de Conservación Guanacaste. She carried out an in-depth survey of nitrogen inputs to the dry forests of Guanacaste, focusing on nitrogen fixation. Her results suggest conceptual models of nitrogen fixation developed in tropical wet forests may not necessarily be appropriate to highly seasonal, dry forests. She was also able to show that tropical legumes exhibit a range of nitrogen fixation strategies or phenotypes ranging from facultative to obligate. Overall, results from her dissertation have shown there is great functional trait variation within what is usually considered a single, well-defined group of species. In 2013, Gei received a pre-doctoral fellowship from the Committee on Institutional Cooperation and the Smithsonian Institution to study the plant-rhizobia symbiosis in tropical legumes. While working at the Smithsonian Tropical Research Institute in Panama, she conducted experiments to determine whether the response of nitrogen fixation to the variation in soil nitrogen in tropical legumes is a function of the plant or the symbiont identity.

As a postdoctoral researcher in the Department of Ecology, Evolution and Behavior at the University of Minnesota, she studied the broad-scale patterns of distribution of legume tree species across neotropical forests. Her goal is to determine whether the variation in a suite of key functional traits, over and above N fixation, among legume species explains their distribution across environmental gradients defined by climate or successional stages in tropical forests.