| dc.description.abstract | Studies related to the quality of the water in coastal environments as bays, estuaries and
tidal creeks are important due to the high productivity and intense influence of anthropic
activities in these areas. This study aims the physical, chemical and microbiological
characterization of diverse tidal creeks along Paraná coast. We analized seasonal
variations in four tidal creeks and differences among rainy and dry periods in two tidal
creeks. The cellular density of the pico, nano and microplanktonic fractions in different
trophic conditions, differentiating the auto and heterotrofic compartments were
performed. The temperature, salinity, pH, alkalinity, CO2, dissolved oxygen, nitrite,
nitrate, ammonium, phosphate, silicate, suspended matter, particulate organic and humic
matter, total chlorophyll, total coliforms and Escherichia coli were analyzed. The pico-
and the nanoplankton were analyzed by direct counting under epifluorescence
microscopy, while the microphytoplankton and the protozooplankton were through the
Utermöhl method. In relation to the physico-chemical and biological characteristics the
Perequê tidal creek exhibited larger saline intrusion, and in the Olho d´Água tidal creek
was detected great amount of discharged domestic effluents. Among the pico- and
nanoplanktonic fractions prevailed the heterotrophic compartment, in both phases. On
the other hand, the abundance of the phytoplankton prevailed under the
protozooplankton in the microplanktonic fraction along the whole study. Differences
between dry and rainy periods were confirmed. In the rainy period was observed in the
two tidal creeks an increase in nitrite, suspended matter, organic particulate matter and
picoplankton and a reduction of nitrate, chlorophyll, nanoplankton (auto- and
heterotrophic) and of the autotrophic microplankton. Increase of phosphate, ammonium
and humic substances were only observed in Barranco tidal creek and of dissolved
oxygen and E. coli in Olho d´Água. These results show that in periods of high
pluviosity elevated amounts of nutrients are exported by the tidal creeks to the adjacent
internal continental shelf. It was not possible to define a pattern for none of the variables
in relation to the tide and to the day and night periods. | |
