A constructivistic learning process was used with primary and secondary students in Genoa, Italy, to approach the problem of the diffusion of the alloctonous algae Caulerpa taxifolia in the northwestern Mediterranean Sea. Because of the lack of a continuous research program in Italy, the media played a heavy role in the transfer of information to the public, and an incomplete report by media personnel often caused great confusion in readers. To reach a self-made opinion about the Caulerpa case, students discussed all general information they could find. They observed that the opposite information often reported by the media prevented people from understanding the ecological problem and participating in its solution, but the group declared the scientists "must" know the answers to the problems produced by the exponential diffusion of the species. The learning process supported the disciplinary curriculum of the classes, allowing them to experience the scientific method and to construct knowledge. Discussion of evidence of differences arising from comparison of scientific reprints and the media promoted an awareness learning. Analysis of the concept map prepared by secondary students and the theater script of primary ones verified the positive impact of the process on students' knowledge. Some basic ecological concepts were well understood. (Contains 21 references.) (YLB)