In order to follow a spring phytoplankton bloom in an area affected by cooling waters discharged from a thermoelectric power plant as well as by high dissolved nutrient concentrations, hydrochemistry and phytoplankton time trends were studied in the industrial area of the Venice lagoon. Samples were collected weekly from the beginning of the bloom until it ended, from February to May 1986, in 10 stations. The centric diatom Skeletonema costatum (Grev.) Cl. (abundances up to 6 x 10(7) cells dm(-3)) was responsible for the bloom; afterwards, the community was mainly represented by phytoflagellates and pennate diatoms. At the end of May, slow growth of various taxa was recorded in the area. Statistical analyses were performed to highlight thermal and chemical effects : results showed that modifications in phytoplankton abundances due to thermal perturbation were only transient. Permanent effects on species composition were not observed, probably because of the strong hydrodynamics of the Malamocco-Marghera channel. The data also showed that thermal pollution was partly masked by pollutant inputs from industrial plant in the study area.
Effects of thermal pollution and nutrient discharges on a spring phytoplankton bloom in the industrial area of the Lagoon of Venice
Socal G;Bianchi F;
1999
Abstract
In order to follow a spring phytoplankton bloom in an area affected by cooling waters discharged from a thermoelectric power plant as well as by high dissolved nutrient concentrations, hydrochemistry and phytoplankton time trends were studied in the industrial area of the Venice lagoon. Samples were collected weekly from the beginning of the bloom until it ended, from February to May 1986, in 10 stations. The centric diatom Skeletonema costatum (Grev.) Cl. (abundances up to 6 x 10(7) cells dm(-3)) was responsible for the bloom; afterwards, the community was mainly represented by phytoflagellates and pennate diatoms. At the end of May, slow growth of various taxa was recorded in the area. Statistical analyses were performed to highlight thermal and chemical effects : results showed that modifications in phytoplankton abundances due to thermal perturbation were only transient. Permanent effects on species composition were not observed, probably because of the strong hydrodynamics of the Malamocco-Marghera channel. The data also showed that thermal pollution was partly masked by pollutant inputs from industrial plant in the study area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
