Epiphytic phytoplankton in response to divergent air pollutants from urban and commercial zones of Chennai District, Tamil Nadu, India: A case study towards phytoplankton based Air Quality Index.

Joseph, Sagaya John Paul; Gopidas, Sreekala Kannikulathel; Gnanam, Gomathi; Boopathi, Sathish Kumar; Subramani, Nagaraj

Microalgae are an effective source of bioindicators to screen any changes of the natural ecosystem in the environment. With the increase in air pollution due to different potential sources, pollution monitoring stations are deployed across the nation with sophisticated analytical methodologies. However, phytoplankton can also serve as an indicator of air pollution as they possess the ability to absorb particulate contaminants. With previous studies on indicator species based on aquatic habitats, this study was carried out to comprehend the interaction between gaseous oxides of sulphur and nitrogen, particulate matter with diameter less than 10 and 2.5 μm (PM10, PM 2.5), with the population density, abundance and frequency of terrestrial epiphytic microalgae from residential and commercial areas of Chennai District, Tamil Nadu. There was a significant correlation between the members of Chlorophyceae, Bacillariophyceae and Cyanophyceae with the abovementioned air pollutants. Cluster analysis, CCA and NMDS analysis were done to find the interaction pattern. The results suggested few indicator species from genera Chlorella, Phormidium, Nitzschia, Navicula, Spirogyra and Oscillatoria. Species of Desmodesmus, Gleocapsa, Gleocyctis and Lyngbya can be considered as an addition to Palmer's list of tolerant species. During this study, the occurrence of filamentous Cladophora crispata is reported for the first time from Tamil Nadu, India. This study unveiled the list of microalgal species resistant to air pollutants from one of the highly polluted cities of India.