How a-Type Anomalies Can Depend on Marginal Couplings

Even dimensional defects and boundaries in conformal field theory support type a anomalies on their world volume. We show that the one-point functions of marginal operators, in the presence of defects and boundaries, are anomalous, and that the Wess-Zumino consistency condition relates them to the derivative of the a anomaly with respect to the marginal coupling. We also argue that the constant term F for odd dimensional surfaces can depend on marginal parameters.