Ecological Studies and Mathematical Modeling of Cladophora in Lake Huron: 4. Photosynthesis and Respiration as Functions of Light and Temperature

Laboratory experiments were conducted with Cladophora glomerata isolated from Lake Huron near Harbor Beach, Michigan, to determine gross and net photosynthesis and respiration as functions of temperature and light intensity. Rates of net photosynthesis and respiration were measured in three replicate cultures at all combinations of eight temperatures (1° to 35° C) and eight light levels (12 to 1235 μE/m 2•sec) using oxygen electrode techniques. Maximum net photosynthesis occurred between 13 and 17° C and 300 to 600 μE/m 2•sec. The data were converted to specific rates of growth and respiration for use in a mathematical model, and three-dimensional response surfaces were generated for gross and net growth and respiration over the entire range of light levels and temperatures examined.