Sensitivity of Bacterioplankton in the Rhine River to Various Toxicants Measured by Thymidine Incorporation and Activity of Exoenzymes

Tubbing, Diny M.J.; Admiraal, Wim

doi:10.1897/1552-8618(1991)10[1161:sobitr]2.0.co;2

Cited by 7 publications

(13 citation statements)

References 17 publications

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“…Table 1 summarizes the acute effects of copper, expressed in 10 and 50% effective concentrations for the three experiments. These values are in the ranges as observed earlier [7]. The sensitivity to copper, expressed in EC50 values, varied threefold among these autumn experiments.…”

Section: Resultssupporting

confidence: 83%

“…Bacterial growth and protein synthesis were estimated as the incorporation rate of [methyL3H]thymidine and t3H]leucine, respectively, in cold trichloroacetic acid (TCA)-insoluble material [6]. Application of this method on bacterial communities of the River Rhine was described in Tubbing and Admiraal [7]. Triplicate samples ( Subsequently, bacterial cells harvested from the copperincubated river water were used for acute sensitivity tests.…”

Section: Methodsmentioning

confidence: 99%

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Successive Changes in Bacterioplankton Communities in the River Rhine After Copper Additions

Tubbing¹,

Admiraal²,

Katako³

1995

Environ Toxicol Chem

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The sensitivity of bacterioplankton to copper was analyzed to see whether initial steps in the selection of copper-tolerant life-forms in mixed populations of bacteria were accompanied by changes in basic metabolic parameters. Analysis took place by measuring the incorporation of [3H]thymidine and [3H]leucine, and the hydrolysis of leucyl-P-naphthylamide over a period of 4 d. In acute toxicity tests the radiochemically determined parameters showed the same sensitivities to copper, whereas in the enzyme test the dose-response curve had a much lower slope, indicating less sensitivity. Marked differences were observed in the susceptibility of the different processes after prolonged exposure to copper. Incorporation of [3H]thymidine, [3H]leucine, and proteolytic activity changed substantially during exposure to concentrations as low as 2 to 31 pg Cu L-I. Higher copper concentrations (126-1,000 pg Cu L-') led in the course of 24 to 48 h to the development of a bacterial community with a higher overall copper tolerance. In winter, these successive events in bacterial populations were observed In the absence of substantial populations of algae or zooplankton. In summer, the metabolic changes in bacterioplankton exposed to copper were strongly affected by the poisoning of other organisms, notably algae, and the subsequent release of organic material. Thus, moderate copper concentrations alter the metabolic profile of bacterial communities, probably as an initial step in the selection of tolerant life-forms.

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Section: Resultssupporting

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Successive Changes in Bacterioplankton Communities in the River Rhine After Copper Additions

Tubbing¹,

Admiraal²,

Katako³

1995

Environ Toxicol Chem

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“…Fuhrman & Azam, 1982, modified as in Tubbing & Admiraal, 1991). Two samples of 50 ml water were incubated with 5nM labelled thymidine (final concentration).…”

Section: Methodsmentioning

confidence: 99%

Seasonal variation in composition and production of planktonic communities in the lower River Rhine

et al. 1994

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1. The composition and activity of phytoplankton, zooplankton and bacterioplankton in the lower River Rhine were measured in 1990 as part of an international biological inventory of the river. A seasonal study was carried out on two stations: one in the river mouth (km 1019) and one at the German/Dutch border (km 863). 2. High densities of phytoplankton (with up to 140 ^ig chlorophyll a P^) and occasional depletion of dissolved silicate were observed at the upstream station. Phosphate concentrations were also lowered during blooms. 3. Phytoplankton blooms, donunated by a few spedes of centric diatoms, declined one order of magnitude during downstream transport. During non-bloom conditions (low) algal densities were maintained during transport, or increased slightly, indicating the suitability of the river reach for alga] growth. ' 4. Bacterial cell ntimber and production (measured by the ^H-thymidine method) showed a broad summer maximum with activity peaks (0.5 nM thymidine h~') coincident with declining phytoplankton blooms. Winter values of bacterial production (0.02-0.05nMh"') were substantial, probably as a result of allochthonous input of organic matter. 5. Rotifers and crustaceans made up the greater part of the zooplankton biovolume, but at the upstream station the contribution of Dreissena larvae and rhizopods was also substantial. High zooplankton biovolumes, of over 500 x 10^nm''l~\ were observed only during the phytoplankton spring bloom. 6. Quantitative relationships between the high phytoplankton production (2.1-3.4 gCm"^ day"^), the high bacterial substrate uptake (0.5-1 gCm"^ day'^), and grazing were analysed for the growing season 1990. Algal grazing by metazoan herbivores was substantial only during spring, while the role of phagotrophic microplankton and cell lysis were indicated as major factors responsible for the downstream decline of phytoplankton blooms in the lower Rhine.

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“…Only for the Dommel sites, 40 nM were added to avoid that higher bacterial activity might lead to a depletion of radiolabeled material. Cell replication was stopped with formaline after 0.5 h, and bacterial DNA was extracted as described by Tubbing and Admiraal (1991). The amount of incorporated 3 H was corrected for quenching and abiotic sorption.…”

Section: Short-term Toxicity Tests With Microbenthic Bacteriamentioning

confidence: 99%

Induced Metal Tolerance in Microbenthic Communities from Three Lowland Rivers with Different Metal Loads

Lehmann

Tubbing

Admiraal

1999

Arch. Environ. Contam. Toxicol.

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The response of microbenthic communities to sustained metal stress was studied in three lowland rivers with different levels of pollution. Tolerance against zinc and cadmium was determined in short-term toxicity tests with microbenthic assemblages colonizing glass discs. Photosynthetic activity served as an endpoint in tests for algae, whereas for bacteria thymidine incorporation was determined. For bacterial assemblages from unpolluted locations, EC50 values in short-term tests ranged between 6.7 and 56.2 &mgr;M zinc, and 8.7 and 25.5 &mgr;M cadmium, respectively. Bacterial assemblages from the two most polluted sites were significantly more tolerant for zinc (EC50: 994 &mgr;M and >1,000 &mgr;M) and cadmium (EC50: 218 &mgr;M and 154 &mgr;M). Results indicated a shift in community composition toward pollution-adapted organisms when a threshold concentration of 1 &mgr;M zinc is exceeded. Although an increasing community tolerance was also indicated for algae, EC50 values for microbenthic algae from all sites exceeded in most cases the highest metal concentrations tested (Zn: 1,000 &mgr;M; Cd: 320 &mgr;M). Since species composition of algal assemblages was found to change at much lower metal levels, it is concluded that short-term toxicity tests measuring photosynthesis inhibition do not reflect well the long-term effects of these metals. Toxic effects of metals on both algal and bacterial assemblages are attenuated by precipitation and complexing capacities of the biofilm.

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Sensitivity of Bacterioplankton in the Rhine River to Various Toxicants Measured by Thymidine Incorporation and Activity of Exoenzymes

Cited by 7 publications

References 17 publications

Successive Changes in Bacterioplankton Communities in the River Rhine After Copper Additions

Successive Changes in Bacterioplankton Communities in the River Rhine After Copper Additions

Seasonal variation in composition and production of planktonic communities in the lower River Rhine

Induced Metal Tolerance in Microbenthic Communities from Three Lowland Rivers with Different Metal Loads

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