Publication Date:
2021-07-16
Description:
In recent years the incidence of algal blooms caused by Nodularia to become one of the serious problems and is threated life of aquatic organisms in the southern Caspian Sea. Nodularia is a Blue-green algae (cyanobacteria group) and due to production of nodularin toxin is importance. In this study, the first, three species of Pseudomonas including aeruginosa, putida and fluorescens were isolated from Tajan river estuary and identified using biochemical tests and compared to standard species. The trend of Nodularia spumigena biomass (log 5) and pseudomonas species (log 7 and 8) were examined in 30 treatments for 10 days in aquarium scale. Parameters such as chlorophyll a, dissolved oxygen, phosphate and nitrate were tested at different time the same time. The results showed that the decline trend of nodularia in aeruginosa and mixed species treatments were better than other treatments and log 8 of bacterium was also more inhibitory effect than to log 7. Similar results were observed in double layer on agar medium and latter treatments had algaecide effect on nodularia. However, putida and fluorescens treatments had algaestatic properties. Concentration of chlorophyll a, dissolved oxygen and nitrate in all treatments, especially aeruginosa and mixed bacteria have been often decreased (p〈0.05). Changes of latter factors in control treatment have been relatively consistent. Although the phosphate changes at different time of relative decline, but nevertheless significant differences were observed. The parameters examined in this study were in direct contact with the algae population and decrease or increase of these factors cause significant change in algae biomass. The conclusion showed that different strains of pseudomonas are able to reduce the population of algae N. spumigena in aquarium scale and the results observed in combination treatment were better than other treatments. The challenge examination of pseudomonas and nodularia in mesocosm scale, evaluation of bacterial metabolites, and also quality and quantity analysis of chemical and biological factors involved in the process is recommended and with achieve reasonable results can be made from this indicator bacteria during algal bloom in the larger ecosystem.
Keywords:
Ecology
;
Iran
;
Caspian Sea
;
Nodularia
;
Pseudomonas
;
Algal bloom
;
Biological control
Repository Name:
AquaDocs
Type:
monograph
Format:
application/pdf
Format:
application/pdf
Format:
42
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