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 the 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 nasses were encountered. A sharp decrease 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.

Bacterial carbon flow in the Humboldt Current System off Chile

“…Bacterial production and abundance in coastal upwelling ecosystems is similar to that reported for other coastal environments and seems to be closely coupled to upwelling cycles (Field et al 1980, Zimmermann et al 1980, Gocke et al 1983, Rheinheimer & Schmaljohann 1983, Hanson et al 1986, McManus & Peterson 1988. In the Benguela upwelling system, BSP has been shown to increase a few days after the peak of PP (Painting et al 1993).…”

Investigations on the Influence of Coastal Upwelling and Polluted Rivers on the Microflora of the Northeastern Atlantic off Portugal. I. Size and Composition of the Bacterial Population

“…Meanwhile, in the southern sections 7 and 9 the phytoplanktonic population had apparently already degenerated and, due to the resulting release of nutrients, a correspondingly large bacterial biomass developed. According to Gocke et al, (1983) the bacterial activity of the further offshore stations in the north was greater than in the corresponding southern stations. The bacterial population of the former, therefore, may still have been in a phase of growth, 'while its development in the latter was more ore less already complete.…”

“…The Chlorophyll a content (Gocke et al 1983) could be determined for those samples extracted from the surface region (4-20 m). It fluctuated between 0.05 and 5.6 μg Γ 1 , and the highest value was demonstrated at Station 152.…”

Bacterioplankton production in the nearshore zone during upwelling off central Chile

“…Although information on bacterioplankton in coastal upwelling ecosystems is scarce, the available data suggest that these systems are not unlike other coastal environments wlth regard to bacterial abundance and activity. Studies of upwelling off Portugal (Gocke et al 1983, Rheinheimer & Schmaljohann 1983, northwest Africa (Zimmermann et al 1980) and southwest Africa (Field et al 1980, Linley & Field 1982 reported bacterial populations on the order of 10' cells 1-l, the great majority of which were not attached to particles. Watson (1978) used indirect methods to estimate that about half of all primary productivity passed through bacteria in coastal upwelling ecosystems.…”

“…It has been estimated that 10 to 50 % of primary production passes through the bacterioplankton (Andrews & Williams 1971, Sieburth et al 1977, Hagstrom et al 1979, Fuhrman & Azam 1982 and that bacteria are dividing about 0.2 to 2 d-' (van Es & Meyer-Reil 1982, Ducklow 1983. Recent work in coastal upwelling ecosystems has shown that bacterial abundance is similar to that in other coastal environments and that it varies in response to the upwebng cycle (Field et al 1980, Zimmermann et al 1980, Gocke et al 1983, Rheinheimer & Schmaljohann 1983, Hanson et al 1986.…”