Cooper served briefly in 1914-1915 as a lecturer in plant ecology at
Stanford University before beginning his long career in the botany department at the University of Minnesota, where he taught from 1915 to 1951. Among his students at Minnesota were
Henry J. Oosting,
Murray Fife Buell,
Rexford F. Daubenmire,
Frank Edwin Egler and Arnold M. Schultz; the latter went on to teach "Ecosystemology" at U.C. Berkeley, and received U.C. Berkeley's "Distinguished Teaching Award" in 1992. Cooper was the president of the
Ecological Society of America in 1936 and the president of the Minnesota Academy of Science in 1937. Other professional accolades included receipt of the
Botanical Society of America's Merit Award in 1956 and the
Eminent Ecologist Award from the Ecological Society of America in 1963. Cooper's travels in
Glacier Bay, Alaska, compelled him to lead scientists in nominating it as a national park or monument. He also established the oldest permanent plot network in post-glacial areas in the world in 1916 in the Glacier Bay basin, now maintained by
Brian Buma at the University of Colorado. At the Ecological Society of America's 1922 meeting, Cooper headed a committee that drafted a resolution adopted by the organization and sent to President
Calvin Coolidge asking him to name the bay a monument. His 1935 monograph on the late glacial and postglacial environment of the Glacier Bay Basin is considered a classic.
Mount Cooper in Glacier Bay is named in his honor. The
Ecological Society of America recognizes Cooper's work in the discipline by bestowing its annual William Skinner Cooper Award on scientists who produce outstanding publications on geobotany, physiographic ecology, plant succession, or the distribution of plants along environmental gradients. ==References==