Interpreting bathyphotometer signals

This study will look at the digital signal obtained from various bathyphotometers employing either photomultiplier tube (PMT) or photodiode detectors. The U.S. Navy standard for measuring vertical distributions of bioluminescence is the High Intake Defined Excitation (HIDEX) bathyphotometer. Bioluminescence signals of the various bathyphotometers will be investigated based on response as compared to HIDEX-2. In recent years, advances in optical instrumentation have led to the development of more compact and more accurate photo-detectors. This has obvious implications in the measurement of bioluminescence, and it is important to ask whether these technologies will increase the capabilities of bathyphotometers. A well-designed bathyphotometer not only will consist of an accurate photodetector but also will take into account issues of temporal and spatial variability of the bioluminescent phenomenon. This is best accomplished by optimizing flow rate in relation to chamber volume while providing adequate stimulation to the organisms.