John D Wehr is a Professor of Biological Sciences at Fordham University and works at the Louis Calder Center - Biological Field Station. He and his students have conducted studies on phytoplankton in large rivers, harmful cyanobacteria blooms, diatom biodiversity, fatty acids in food webs, road salt effects on river algae, and ecological stoichiometry. Currently he is studying impacts of drought and hydroelectric dams on epiphytic algae in the Colorado River with Dr. Larry Stevens.