Probing the Depths of Crater Lake: A Century of Scientific Research by Douglas Larson
During the summer of 1947 and again in August 1950, ranger-naturalists collected samples of vegetative material from submerged rocks and sediments along the shore of Wizard Island. The samples were sent to H. E. Sovereign in Seattle for analysis. Sovereign, whose expertise was the taxonomy and ecology of diatoms, identified 112 diatom species, several of which were described as new and rare. These findings demonstrated that life in Crater Lake, in this case the lake’s diatom populations, was far more diverse and complex than earlier scientists had believed. The findings also showed that a significant portion of the lake’s algae lived attached to the wave-swept surfaces of submerged rocks and sediments in shallow waters, unlike the phytoplankton that lived suspended in the lake’s open waters. Most important, perhaps, the discovery of new and rare diatom species added to the world’s inventory of diatoms and other algae. It also broadened scientific knowledge about the ecology of diatoms, that is, the interaction of diatoms with their environment, in this case a deep, clear lake in which life is adapted to harsh weather, barren waters, and limited growing conditions.
Like J. S. Brode, who had studied the lake independently during the mid-1930s, many of the Crater Lake scientists worked as summertime employees of the National Park Service. During their off hours, provided that boats and equipment were available, they pursued their special research interests on the lake. John R. and Joanne Rowley, for example, were botanists at the University of Minnesota who spent their summers working at Crater Lake as ranger-naturalists. Their summertime research contributed further to the growing lexicon of knowledge about the nature of Crater Lake.
In July and August 1954, C. W. Fairbanks, a ranger-naturalist, and John Rowley spent several days on the lake collecting plankton, benthic invertebrates, mosses, and fish. Using a trap device, they collected plankton from various depths and grabbed benthic invertebrates and mosses from the lake bottom using an Ekman dredge and a Peters grappling hook. Samples were collected in Fumerole Bay, at Cleetwood Cove, offshore of the Wineglass (a prominent rockslide), and at two or three locations in the middle of the lake. They recorded three temperature gradients, obtained Secchi-disk readings, and collected fish for size measurements and stomach analyses. Fairbanks and Rowley made (1) mosses were found at depths ranging from 85 to 425 feet; (2) six species of flowering plants were collected, including water buttercup (also collected by Brode in 1935) and Pennsylvania bittercress, with large beds of these plants covering the bottom of Fumerole Bay eight to ten feet below the surface; and (3) an unusual invertebrate called a “water bear” (Class Tardigrada) was found among mosses and other vegetation collected from Fumerole Bay. In 1956, while dragging a grappling hook across the lake bottom northwest of Wizard Island, Rowley made a rare find by snagging a flowering plant identified as Myriophyllum verticillatum, or whorl-leaved water milfoil. Three years later, on July 14, 1959, Kuno Thomasson of the Vaxtbiologiska Institutionen of Uppsala, Sweden, collected phytoplankton samples from Crater Lake. Thomasson noted that the phytoplankton was “very sparse” and identified several new species for the lake.