Ecological and laboratory studies on the role of luminous bacteria and their luminescence in coastal pollution surveillance

Abstract

This study was aimed at finding out how bacterial bioluminescence, a trait very sensitive to toxicants, is affected in coastal environs which receive various types of effluents. For this, observations on occurrence and distribution of visibly luminous bacteria from both polluted and nonpolluted environments were documented during a 7 yr period. While luminous colonies were abundant, often contributing over 10% of the total colony-forming units in the pollutant free areas, none of over 200 water, sediment, fish, shellfish and plankton samples from the polluted localities yielded any visibly luminous colony. On analysing several bacterial strains originating from the latter environment, it was evident that there were many dark (nonvisibly luminous) strains of the usually luminescent Photobacterium leiognathi. Laboratory studies on the effect of various chemicals on light emission by different luminous species suggested a strong depression (and/or irreversible loss) of luminescence in them. Results of this study suggest that in addition to several advantages known with these bacteria, they are useful as biomarkers in the assessment of environmental health.