Representation, dispersion, and variation of bacterial indicators in the coastal waters of Nagore (east coast of India)

Abstract

The occurrence of bacterial indicators in the coastal waters of Nagore on the east coast of India was studied during two monsoon and nonmonsoon cycles from 1995 to 1996. Proteus/Klebsiella, Virbio parahaemolyticus, and total coliforms were generally present at a mean level of 10 u9 cfu/g dry sediment, whereas other indicators such as Salmonella, Shigella, and V. cholerae were at the 10 u5 level. In the water column, total coliforms and Salmonella, Shigella, and V. cholerae were at the 10 u5 level. In the water column, total coliforms and Salmonella were 2 to 3 orders of magnitude lower than in sediment. Higher numbers of indicators were retrieved at 10- and 15-m depth lines than at a 5-m depth line. While southwest monsoons caused increased bacterial input to the coastal sediment of Nagore, cyclonic effect on indicators was observed only in the water samples. Although physicochemical parameters did not influence the variation in coliform population significantly, most of the indicators in the sediment showed significant negative correlation with chlorophyll a, indicating an inverse relationship between them. With ever-increasing development of Nagore, nonpoint sources of pollution may become a serous problem. Continued monitoring of these groups of bacteria over longer periods of time would help develop models for their regulation and may suggest remedial measures