The School of Oceanography and the Electrical & Computer Engineering Department at Oregon State University will undertake a collaborative project to design and construct a reflective-tube chlorophyll absorption meter using quantum well technology light emitting diodes (LEDs). The instrument will make in-situ measurements of chlorophyll absorption at 675 and 750 nm. The key to this instrument is the applica- tion of newly developed LED technology. A new dual wave- length light source at 675nm and 750nm will be designed and fabricated. They will then be placed in a prototype instru- ment and validated. The absorption meter will measure the ratio of light source output to received signal at a fixed distance within the submerged tube. The ratio of light emitted to that received at the wavelengths of maximum chlorophyll absorption will then indicate the abundance of chlorophyll and phaeophytin pigments in the water. Such information is important in a variety of ecological, environ- mental, and remote sensing studies. The absorption meter will provide an unobtrusive measure of chlorophyll abundance and represents a major improvement over present methods of making these measurements using fluorometers. Furthermore, the LEDs require very little power so profiling and long-term mooring applications are more feasible.
