Impact of lockdown on the environmental quality along the Indian coast and a tropical estuary

Abstract

The COVID-19 lockdown significantly improved the global environmental quality by restricted anthropogenic activities. We aimed to understand the response of Indian coastal environmental quality and an estuarine (Zuari estuary, central west coast of India) water quality to the lockdown using satellite-derived data sets and in-situ measurements, respectively. The in-situ study was carried out for two weeks (during August and September 2020) to measure chlorophyll-a and macro-nutrients. Recent 5-years (2015-2019; March-August) data sets of aerosol optical depth (AOD), rainfall, air temperature, sea surface temperature (SST), chlorophyll-a, particulate inorganic carbon (PIC) and particulate organic carbon (POC) were compared with lockdown period (2020). The AOD was decreased during the lockdown period (23 ± 11%) as compared with recent 5-years shows the significant impact of lockdown on industrial, transport and urbanization activities. The water quality parameters and chlorophyll-a biomass have remained similar to the past data sets, indicating the insignificant effect of lockdown on these parameters. The results of the case study were compared with the previous reports, which showed a decrease in the concentration of nitrate, phosphate and silicate and comparable concentration of chlorophyll-a. Recent studies show significant impacts of lockdown on the atmospheric parameters and water quality parameters, however the present study did not observe any significant variations in the in-situ and satellite derived data sets of water quality and chlorophyll-a. We have discussed the possible reasons underlying in the less/undetectable response of the chlorophyll-a and water quality of the Indian coastal waters and estuaries during the lockdown.