Fig. 5. Plots of the effects of amiloride on metabolite uptake rates (A—C) (µmol g^-1 h^-1) and proton elimination rate (D) (µequiv g^-1 h^-1) by Riftia pachyptila. Worms were maintained under in situ conditions (see Materials and methods) until they exhibited signs of autotrophy. The arrow denotes the time at which amiloride was added to the seawater to achieve a final concentration of 1 mmol l^-1. A flow of fresh seawater was maintained through the aquaria after exposure to amiloride. Rates are expressed in terms of wet mass.