Investigations on the Influence of Coastal Upwelling and Polluted Rivers on the Microflora of the Northeastern Atlantic off Portugal. II. Activity and Biomass Production of the Bacterial Population

Abstract

During May, 1981 the following parameters were measured in the sea area off the west and south coast of Portugal: concentration of monosaccharides, number of actively metabolizing bacteria, maximum uptake velocity and turnover rate of glucose, specific activity rate of the microbial population and bacterial production. A good correlation between the activity parameters was found in all water samples. Highest values of bacterial activity were measured in the region off mouth of the Tejo River. Apart from this eutrophied area high bacterial activity was detected in the offshore region of the northern part of the study area (off Porto) and in the nearshore region of the Algarve coast, where aged upwelled water masses were encountered. A sharp decreae was found with increasing depth, where at 100 m and deeper the activity parameters and the number of active bacteria sometimes dropped below the detection limit. The concentration of monosaccharides did not reflect these strong regional and vertical differences.