A limnological oxidation technique, based on procedures employed in soil chemistry, was developed and tested by use of purified organic compounds and various natural substrates. A sample is oxidized by dichromate in a strongly acid medium maintained at 100 C. The amount of dichromate reacting (determined titrimetrically as the difference between the initial and final quantities) is reckoned as Oxygen Consumed, or weigh of oxygen required by the sample. The oxidation serves as the principal step for sensitive determinations of organic carbon (as CO2) and nitrogen (as NH3).

In this thoroughly updated third edition, the authors provide a series of carefully designed and tested field and laboratory exercises that represent the full scope of limnology. In using the text, students will gain a solid foundation in this complex, multidisciplinary field of ecology as they explore the physical, chemical, and biological characteristics of standing and running waters. The book illustrates accepted standard methods as well as modern metabolic and experimental approaches and their research applications. Each exercise is preceded by an introductory section and concludes with questions for students as well as suggestions for further reading. As a textbook, this is a highly structured, concise presentation with a research-oriented approach that openly invites active participation by students.

Limnological Analyses, a classic, second, thoroughly updated edition, consists of a series of carefully designed and tested field and laboratory exercises covering the full scope of limnology. It provides the student with a solid foundation in this complex multidisciplinary field of ecology and illustrates modern experimental approaches. Among the topics covered by such exercises are: major physical components of lakes and streams; important mineral nutrients; cycling of organic matter; benthic fauna; primary productivity of phytoplankton; quantitative methods in biota analysis; diurnal changes; experimental manipulation of model ecosystems; effects of sewage outfall and other human activities; whole ecosystem and community analyses. Each exercise is preceded by an introductory section and concludes with questions for the student and a selection of suggested reading. Teachers and students of limnology will value Limnological Analyses for its highly structured, concise presentation. Its research-oriented approach encourages active participation.

Fluctuations in strength of year classes from 1945 to 1956 of Yellowstone Lake cutthroat from Pelican and Chipmunk Creeks are compared with the parental stock and several climatically influenced factors of the environment. Variations in year-class strength in the two tributaries were highly correlated with fluctuations in lake water levels. Strong year classes occurred in yeas of low water. Female spawner escapement, timing of the runs, and summer air temperatures were not significant factors. A formula based on water levels is presented for predicting year-class strength in Pelican Creek and in the Fishing Bridge area fishery. Stocking of fry in years of high water is suggested as a means of supplementing natural production. A method of forecasting lake water levels several months in advance of their occurrence is discussed.