Microfouling of Manganese-oxidizing microorganisms in Rameswaram Coastal Waters.

Abstract

Manganese oxidizing marine microorganisms was studied from the coupons of PVC, Titanium, Brass, Copper and Stainless Steel were immersed one meter below water surface, using wooden rafts. The metal coupons, Brass, Titanium and Brass were exposed for a period of six months (October 2005 to March 2006). The PVC and SS were suspended in the sea for two months (February and March 2006). Sea water samples were also collected from the study area using water sampler to estimate the physiochemical and nutrients were analyzed. The population of HB and MHB on PVC was registered as 3.62 x 107 CFU/cm2 and 2.87 x 107 CFU/cm2, respectively while on Stainless Steel the population density of HB and MHB was recorded as 3.79 x 105 CFU/cm2 and 1.34 x 105 CFU/cm2. The PVC and titanium coupons were recorded relatively higher values comparing with other coupons, and it may be due to the non-toxic nature of the substratum. Brass also recorded higher bacterial population density compared to copper. The least population density observed in copper coupons could be due to it toxic nature. The generic composition of heterotrophic bacterial strains isolated from biofilm samples, both Gram-positive and Gram-negative groups were noted on all the materials studied. The notable thing was that Gram-positive group was fond to be dominant. The genera identified under Gram-positive were Bacillus sp., Staphylococcus sp. and Micrococcus sp. and the Gram-negative strains identified as Pseudomonas sp., Salmonella sp., Vibrio sp. and Proteus sp. Among the five types of coupons tested PVC exhibited highest Mn value of 5543 mg/g. Bacterial slim samples generated on the exposed coupons were scrapped and characterized by Bergey’s method.

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