Experimental outdoor studies with ulva fasciata delile. II. Trace metal chemistry

Abstract

The effect of light and nitrate/nitrogen on the uptake of iron, manganese, zinc, cadmium and rubidium by Ulva fasciata Delile grown in outdoor continuous cultures was investigated. As the major determinant of growth in this experiment, light level exerted a greater overall effect than nutrient level on metal uptake by U. fasciata. Concentrations of cadmium and rubidium in the algae decreased as the specific growth rate increased. Algal nitrogen content controlled the uptake of zinc and iron. The concentration of manganese in this seaweed increased as specific growth rate increased. Because environmental growth factors may indirectly affect trace metal uptake, seaweed populations at different locations may have trace metal chemistries that are related differently to the chemistry of local waters. Growth characteristics should be considered when seaweeds are used as trace metal pollution indicators.