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Data of Thesis


Author: Luciana de Paula Lima e Schimidt de Andrade

Title: The influence of high concentrations of zinc in phytoplankton species in Sepetiba Bay, Rio de Janeiro, Brazil.

Year: 1993.    Full text (in Portuguese)


Sepetiba bay is a water body of fisheries and sonial importance that suffers from metal pollution coming mostly from a zinc and cadmium industry. Several researches have been performed concerning the bay. Three phytoplanktonic species from this water body were studied in laboratory cultures as a contribution to the knowledge of their physiology. Phaeodactylym tricornutum,. Chlorella sp. and Synechocystis sp. were cultivated under increasing zinc concentrations (control= 22µg.L-1; 20Zn=440 µg.L-1; 50Zn= 1100 µg.L-1; 100Zn= 22µg.L-1) and evaluated by means of culture growth (cel1 number • ml- 1), concentration o f chlorophyll a, carbohydrates and proteins. These cultures obtained data were compared taking into account the maximum chlorophyll a and protein concentrations as well as the minimum carbohydrate concentration during the exponential growth phase. The primary production measured with NaH14CO3 (µgC.µgChla-1.h-1) was determined in the exponential phase and the photosynthetic activity was ,calculated. The zinc incorporated to the cells quantified at the end of the cultivation periods by atomic absorption spectrometry. The high zinc levels led to an increase in chlorophyll a synthesis for the three species (up to 85%), and to a and Synechocystis sp. ( 47%). Photosynthetic activity was increased for all contaminated cultures for t he three species, with the exception of 100Zn condition of Chlorella sp,. At the enc of the cultivation periods Zn had been incorporated into the cells of P . triconutum (up to 1400%) and Chlorella sp. (up to 350%) . The conditions 20ZN, 50Zn and 100Zn de Synehocystis sp. incorporated less Zn than the control, indicating a detoxification process for this species. As this three species showed ability to grow even in the mentioned high zinc levels concentrations, and P. tricornutum and Chlorella sp. showed also ability to concentrate this metal, it can be concluded that this is certainly a process that allows zinc to be transferred to other trophic levels in natural environment ..