List of Articles Anabaena flos- aquae - N: P ra

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  1 - The determination of N: P ratio in Cyanobacterial bloom of Anabaena flos- aquae in the Caspian Sea, Iran in situ
  Maryam Fallahi S.Mohammad Reza Fatemi Ali Mashinchian Atoosa Noori Koupaei
  Introduction: The aim of this study is determining the N: P ratio which causes the maximum bloomof toxic cyanobacteria: Anabaena flos- aquae of the Caspian Sea and finding the N: P ratio thateliminates its bloom. To perfect this study, the effect of different phosphorus More

  Introduction: The aim of this study is determining the N: P ratio which causes the maximum bloomof toxic cyanobacteria: Anabaena flos- aquae of the Caspian Sea and finding the N: P ratio thateliminates its bloom. To perfect this study, the effect of different phosphorus concentrations on thegrowth level was also inspected.Material and method: The experiments were carried out in situ (the temperature and light intensitywere kept at 25± 2 degrees centigrade and 3500± 350 lux respectively). Different N: P ratios andvarying phosphorus concentrations were applied as treatments with respect to logarithmic calculations.Three replicates were considered for each treatment and one control (Zinder media). The laboratoryexperiments lasted 96 hours. Visual counting at the start and end of the experiments were carried outto assess the growth percentage.Results: In this project, Anabaena bloomed in Zinder media (control) with 9.9 μg/lit ofnitrogen, 2.96 mg/lit of phosphorous and the 0.0033N:1P ratio.N: P ratios of 15: 1 to 22: 1 resulted in the maximum bloom of Anabaena flos- aquae. The maximumlevel of growth percentage was reached to 5219.84± 1486.69 in 18.15N: 1P ratio with 53.72 mg/lit ofnitrogen and 2.96 mg/lit of phosphorus. The bloom ended at 218.86N: 1P.Studies on the effect of phosphorus concentration showed phosphorus concentration in Zinder media(2.96 mg/l) is the optimum value for Anabaena bloom.1- Associate Professor, Inland waters research institute, Bandar Anzali2- Assistant Professor, Department of Marine Biology, Science and Research Branch, Islamic Azad University3- Assistant Professor, Department of Marine Biology, Science and Research Branch, Islamic Azad University4- PhD. Department of Marine Biology, Science and Research Branch, Islamic Azad UniversityAbstracts of Articles in EnglishJ.Env. Sci. Tech., Vol 17, No.2, Summer 2015190Conclusion: The whole results indicate, although in the presence of enough phosphorusconcentration, Anabaena bloomed even with low nitrogen concentrations (9.9 μg/l in Zinder media)by fixing atmospheric nitrogen when enough phosphorus and nitrogen concentrations supplied withlow N: P ratio the maximum bloom intensity was observed. Manuscript profile