The eco-physiological responses of three
nitrogen-fixing cyanobacteria (N-fixing cyanobacteria),
Aphanizomenon gracile, Anabaena minderi, and Ana.
torques-reginae, to light were assessed under nutrient
saturation. The N-fixing cyanobacteria were isolated
into monocultures from a natural bloom in a shallow
colored lake and their growth irradiance parameters and
pigment composition were assessed. The different
ecological traits related to light use (lmax, a, Ik) suggest
that these N-fixing cyanobacteria are well adapted to
low light conditions at sufficient nutrients, yet interspecific
differenceswere observed.Aphanizomenon gracile
and Anabaena minderi had high relative growth rates at
lowirradiances (ca. 70%of those in high light), lowhalf
saturation constant for light-limited growth (Ik
9.09 lmol photon m-2 s-1) and high efficiency