A small excursion leads us to the ocean floor. In numerous sediment samples we find foraminifera, microscopic single-celled organisms with calcitic shells, attached to hard substrates on the sediment surface. These samples were taken in the Strait of Gibraltar. The cibicids shown in the picture colonize elevated substrates in these regions to collect food transported by sustained bottom currents. They are highly adapted and use these habitats as ecological niches.