Investigation of Bacteria in coastal waters of King George Island

We determined the numbers of free-living and associated (aggregated or bonded with particles) bacteria in the coastal water of King George Island at an offshore (St. 1) and a nearshore station (St. 2) as a function of physico-chemical parameters. Water sampIes were collected between March and October at St. 1 and between April and October at St. 2. Direct counts of total bacteria varied from 0.53*10**8 to 5.02*10**8 cells/l. Associated microorganisms accounted for 5 to 20 % of the total number of bacteria. Strong Spearman and Pearson correlations were observed (R = 0.82; P = 0.001) between the numbers of free-living and associated bacteria at St. 1. These two groups of bacteria were nearly evenly distributed in the horizontal transects from inshore to offshore waters at depths of 1-10 m in Ardley Cove. There were no substantial differences in the numbers of either free-living or associated bacteria in vertical transects too. Their number at St. 1, but not at St. 2, correlated significantly with all tested environmental parameters (salinity, temperature, solar radiation, nitrate, phosphate and chlorophyll a concentrations), except nitrite concentrations in water. The most probable reason for these correlations is that a common seasonal trend is characteristic of most tested parameters during the March to October period.