The Deep-Sea Chlorophyll Sensor utilizes fluorescence detection technology to measure chlorophyll-a concentration in marine environments. By exciting chlorophyll-a in algae with blue light and detecting the emitted red-band fluorescence, the sensor accurately infers chlorophyll-a levels. It features high sensitivity, rapid response, and is suitable for integration with mobile platforms such as Argo floats and underwater gliders, as well as fixed platforms like moorings and ship-based water samplers for deep-sea chlorophyll-a monitoring.