Nitrogen fixation (A) and accumulation of ammonium (B) in nitrogen-free synthetic growth medium during the
growth of Bacillus pumilus and Chlorella vulgaris cultured alone and jointly in immobilized alginate beads. Joint
immobilization without nitrogen (diagonal filling); B. pumilus immobilized without nitrogen (vertical filling); B. pumilus
immobilized with nitrogen (horizontal filling). Bar whiskers represent SE; their absence indicates negligible SE.