
Fig. 7. Oxygen/sulfide ratio in Geukensia demissa gills (circles) and Mytilus edulis gills (squares) as a function of Na2S concentration. Gills were exposed to 0.5 µmol l-1 5-HT (open symbols) or 10 µmol l-1 5-HT (filled symbols). Values are means ± S.D. (N=3). To eliminate overlap of error bars, some points have been offset by 10 µmol l-1. Lines serve only to connnect data points.