GAMETOPHYTIC GROWTH BY MACROCYSTIS PYRIFERA (PHAEOPHYTA) IN RESPONSE TO VARIOUS IRON AND ZINC CONCENTRATIONS1

Batch culturing experiments were conducted to examine effects on Macrocystis pyrifera (L.) C. A. Agardh gametophytic growth of various iron and zinc concentrations in the chemically defined, artificial seawater medium, Aquil. A least squares fit of experimental data represented the relative importance of these micronutrient effects. Optimal iron and zinc concentrations in Aquil were estimated at 340 nM (7 × 10^?11 nM as Fe³⁺]) and 135 nM (6 × 10^?2 nM as Zn²⁺]), respectively.