Final answer:
A spectrophotometer is typically used for identifying the absorption spectra of pigments in photosynthetic organisms, and not for measuring the O2 produced during photosynthesis. For oxygen measurements, other methods such as gas volume change or oxygen-sensitive electrodes are used.
Step-by-step explanation:
A spectrophotometer can be used to measure which wavelengths of light are absorbed by photosynthetic pigments in an organism by generating absorption spectra. However, a spectrophotometer is not typically used to measure the actual amount of O2 produced during photosynthesis. Instead, to measure oxygen production, scientists might use an apparatus that measures changes in the volume of gas in a closed environment or employ oxygen-sensitive electrodes. Additionally, to measure the metabolic rate related to photosynthesis and respiration, one could use an oxycalorimeter for indirect calorimetry, which measures the volume of oxygen consumed to estimate the caloric value of oxidation in organic nutrients.