[2] As a teenager, the National Science Foundation selected her for a summer placement in the laboratory of Donald Ritchie at Barnard College.
She also completed a summer program at Colorado State University, and spent time working in a molecular biology lab.
[citation needed] Ehrenfeld worked on wetlands ecology and was particularly interested in the relationships between biodiversity and human disease.
[3] Ehrenfeld investigated how the Berberis thunbergii (Japanese barberry) impacted soil processes and micro-organisms.
[6] She found that barberry tissue is high in nitrogen-rich compounds akaloids, which causes a loss of organic matter in nearby soil due to excessive nitrogen cycling.
[6] Ehrenfeld removed barberry in the Morristown National Historical Park and attempted to restore native shrubs (spice-bush and witch-hazel).