Seasonal effluxes of microbial pollution and physiochemical assemblages along south east coast of India during southwest and northeast monsoon

Abstract

Three interrelated zones were examined to analyze the trend in physicochemical and microbiological parameters assemblages especially at the southwest (premonsoon) and northeast monsoons (monsoon) in Nagapattinam district and its surroundings. To comprehend the influence and pattern of pollution at beachgoer/pilgrim/fishing ports, various coastal sites including Nagapattinam, Nagore, and Velankanni coastline spatial, were studied. A total of 30 physiochemical parameters (split into anion/cation and nutrient parameters) and fifteen microbiological parameters were examined from 76 samples belonging to estuary, intermediate, and onshore regions. It revealed that the coastal water body was radically influenced by the input of freshwater during northeast monsoon. Significantly silicate (SiO 4) was found to be higher ranges from 11.99 to 392.29 μM during northeast monsoon at estuary and intermediate zone. TN, NH3, DO and Chlorophyll-a (chl a) were increased in northeast monsoon rather than southwest monsoon at estuary and intermediate zone, whereas Chlorophyll-b (chl b), NO2, NO3, and PO4 were increased in southwest monsoon. The northeast monsoon has a higher concentration of pollution indicators in water and sediments than southwest monsoon, in the following order; TVC>TC>TV>TS>FC>FS. In order to explore the shoreline pollution condition; Nagore regions showed higher bacterial load followed by Velankanni, Nagapattinam, North Poigainallur and South Poigainallur; Additionally, for coastal transects, the bacterial load was followed by NS 0.5>NS>2B>NS E3>NC; and 0.5 displayed a immense escalation of bacterial pollution indicators. Significantly the elevated bacterial load during northeast monsoon has diffident connection with NH3, suggesting that surface waters may comprise NH3 oxidizers; with the exception of DO and TN. TN showed a positive correlation between DO and SPM, whereas TP showed a negative correlation between DO and SPM. Typically, in a principal component analysis, all microbiological parameters (except PI-Pollution Index) had high loading (above 0.90) with 36.046% of variance.