TY: JOUR T1 - Differential inter-and intra-specific responses of Aphanizomenon strains to nutrient limitation and algal growth inhibition A1 - De Figueiredo, Daniela R. A1 - Gonçalves, Ana M. M. A1 - Castro, Bruno B. A1 - Gonçalves, Fernando A1 - Pereira, Mário J. A1 - Correia, António N2 - Cyanobacterial blooms of Aphanizomenon spp. occur worldwide, with deleterious effects on aquatic communities. The present work aimed to investigate the effects of different levels of phosphorus and nitrogen on the growth of Aphanizomenon bloom-forming strains, belonging to the species A. issatschenkoi, A. aphanizomenoides and A. gracile. Algal inhibition tests were also performed to assess the potential allelopathic effects of the strains? ?ltrates on the growth of four green algae (Pseudokirchneriella subcapitata, Chlorella vulgaris, Pandorina morum and Coelastrum astroideum). Phosphorus had a signi?cant effect on the growth of all the strains tested; orthophosphate concentrations 0.3 mg PO4 32 L21 led to a decrease of more than 50% in the cyanobacterial growth of most strains. The growth of A. gracile strains was unaffected by variation in nitrate levels, but strains of A. issatschenkoi (UADFA1) and A. aphanizomenoides (UADFA6, UADFA7 and UADFA13) were moderately to extremely sensitive to nitrate depletion in the medium. These results strengthen the idea that intra-speci?c variation may play an important role in bloom dynamics; however, culture conditions and mutations may explain the morphological and physiological changes observed. Allelopathic assays revealed signi?cant inhibition of microalgal growth by ?ltrates of strains from the three species, but also indicated intra-speci?c differences in allelopathic activity. UR - https://ria.ua.pt/handle/10773/25190 Y1 - 2011 PB - Oxford University Press