An integrated fluorometer is a tool used to measure the amount of light a sample of water produces in response to a certain wavelength of light. Light travels through the sample in the form of wavelengths, which can be detected and measured. When the amount of light passing through the sample is measured, it creates a "fluorescence profile" that scientists can use to identify various substances in the water. This is useful for water quality testing, because it can identify pollutants or other contamination that may be present.