The effect of orthophosphate concentration on the growth of articulated coralline algae (Rhodophyta)

The growth of articulated coralline algae is significantly inhibited by a medium enriched with orthophosphate at a concentration normally used in culturing other groups of marine algae. A medium with one quarter or less of this phosphate concentration promotes the growth of coralline algae in culture. These results are related to the observation that phosphates are crystal inhibitors of calcification. The absence or presence of coralline algae in certain types of habitats may thus prove to be a reliable biological indicator of relative levels of man-made phosphate pollution in seawater.