Effects of copper on early developmental stages of Lessonia nigrescens Bory (Phaeophyceae)

Copper effects on the early developmental gametophytic and sporophytic stages of the kelp Lessonia nigrescens were tested in gradients of increasing concentrations of ASV-labile copper. The results demonstrated a high sensitivity to copper of all life-history stages of the alga, where even the lowest tested concentration affected spore release as well as their subsequent settlement. More significant, concentrations higher than 7.87 microg L(-1) totally interrupted the development of the spores after they settle. This effect led to a failure in the formation of male and female gametophytes and, as a consequence, to a complete disruption of the normal life cycle of the kelp. Thus, we suggest that the absence of L. nigrescens from copper-enriched environments results from the high sensitivity of its early life cycle stages, which limits growth and maturation of the gametophytic microscopic phase and, as a consequence, prevents development of the macroscopic sporophytic phase.