Figure 4.

Contraction patterns of Tethya wilhelma during extracorporeal glycine application (a - b): Projected area of two specimens of T. wilhelma before and during glycine application (grey background). Glycine induced bi-phasic contractions in all experiments and attenuated the contraction amplitude (b; see additional file 4: Movie_S4.mov for the time-lapse movie of Fig. 4b). Filled arrowheads indicate the points in time when stock solutions of the substances were injected into the experimental reactor circulation system to reach final concentrations of 1.3 mM.