John W. Marr received his PhD in Ecology from the University of Minnesota in 1942, under William S. Cooper. His dissertation research was on the ecology of the forest-tundra ecotone on the east coast of Hudson Bay.
During World War II, Marr served as Arctic Regions Specialist with the Air Force, and was stationed for a time in Greenland.
In 1944, he joined the faculty of the Biology Department at the University of Colorado, Boulder, where he continued until his retirement in 1982. At that time, he received the Stearn's Award for exceptional service to the University.
Marr's observations in the alpine areas of Colorado convinced him that processes operating in the winter played a major role in the ecology of the region. Since very little data were available, he established a year-round environment measurement program in 1951 with the aid of federal grants. One station in each ecosystem region has continued to operate.
Marr founded the internationally-known Institute of Arctic and Alpine Research (INSTAAR) in 1951 and was its director until 1967 when he resigned in order to devote more time to his own research. He developed the University's Mountain Research Station as a year-round teaching and research facility and secured funding to build an Alpine Laboratory which was later named the John W. Marr Alpine Laboratory in his honor. The alpine areas on Niwot Ridge thus became accessible to students and researchers from many parts of the world.
His classic monograph, "Ecosystems of the East Slope of the Front Range in Colorado", describes ecosystems present as well as the relationships between organisms, physical environment, and ecological processes.
Marr died in October, 1989, following a long illness with Parkinson's Disease.