Distribution and biochemical activity of heterotrophic bacterial population off Madras coast

The quantitative distribution and biochemical activity of heterotrophic bacteria capable of multiplying in organic media of pertinacious composition from, shelf and slope waters off Madras coast between 1 lo 30' N and 14 30' N were studied during March, 1986. The percentage of samples yielding more than 100 X 105 / ml colonies was only 12 in number in depth range 0-10 metres. Pigmented bacteria was encountered more in this depth range. Faecal coliform bacteria was not encountered throughout the observations. Total bacterial count varied from 8.6 X 105 to 3.08 X lo7/ ml in spread plate method of isolation. Pseudomonas, Vibrio, Alcaligenes, Flacvobacterium, Cytophaga, Agarobacterium and Chromobacterium formed the predominant flora isolated. Their correlation with environmental parameters like temperature, salinity, oxygen and pI 1 are discussed. The cultures were more proteolytic than amylolytic which indicated the process of organic decomposition and vigorous liberation of plant nutrients in these latitudes.