Biological control of bloom algae in the southern of Caspian Sea

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

Determination of sediment nutrients in the cage fish culture area (before breeding) of the southern Caspian Sea (Mazandaran coast-Kelarabad)

This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were prepared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophorous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degradable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P>Ca-P>FeP>Al-P>Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorption and desorption were temperature, Eh and pH. Also, the form of NH4+/N was of a high percentage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottom water, it finds that released of those from the sediments to water will be happened with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom