Detection of spontaneous fluorescence in algae under marine pollutant stress

Currently, the detection techniques for assessing environmental stress in active microalgae are fraught with complexities, expensive, and poor timeliness. Therefore, this paper introduces an algal fluorescence excitation and detection device based on spontaneous chlorophyll fluorescence, aimed at investigating the effects of marine pollutants on algal stress. In the experiments, different concentrations of mercuric chloride (HgCl₂) solution were added to algal samples. Under the pollutants stress, the fluorescence intensity of the algae weakened, and it continued to decrease as the stress time to the pollutants increased; under the same stress duration, higher concentrations of pollutants resulted in faster decreases in fluorescence intensity. Similarly, this device was also used to detect the stress effects of cadmium chloride (CdCl₂) and sodium hypochlorite (NaClO) solutions on Chlorella. This paper proposes a simple, convenient algal fluorescence excitation and detection device for studying the impact of heavy metals and common inorganic substances in bleach on the fluorescence excitation characteristics of Chlorella. Experimental results demonstrate the feasibility of using the proposed algal fluorescence excitation device to detect the concentration and stress time of pollutants stressing the algae.