E. Marcelo Acha is a biologist; his research interests focus primarily on plankton ecology, fish reproduction and ichthyoplankton. His current research activities are related to the role of marine fronts on diversity and biological production of the Argentine Sea, and its effects on the life histories of the species in the region. He is currently member of the National Council of Scientific of Scientific Research and Technology (CONICET); member of the Fisheries Ecology Project (INIDEP), and develops teaching activities at the Mar del Plata University (Argentina). Alberto R. Piola is a physical oceanographer; was Visiting Investigator at the Woods Hole Oceanographic Institution and Research Staff at Lamont-Doherty Earth Observatory of Columbia University. He is currently Research Director at Servicio de Hidrografia Naval, Argentina and Professor of Oceanography at Universidad de Buenos Aires, Argentina. His research is focused on the large scale ocean circulation, regional oceanography and the biological and biogeochemical impacts of ocean fronts. Oscar O. Iribarne is an ecologist; his research interests focus primarily on understanding the role of ecological processes in determining diversity and secondary production on marine ecosystems. He is currently member of the National Council of Scientific Research and Technology (CONICET, Argentina), full Professor at the National University of Mar del Plata (UNMDP, Argentina) and Director of the Institute of Marine and Costal Research (IIMyC, Argentina). Hermes W. Mianzan was a biologist dedicated primarily to the study of the ecology of gelatinous plankton. He was one of the leaders in thought and practice as the vision of planktonic dynamics grew to increasingly incorporate interactions between physical and biological processes, particularly involving his specialty of gelatinous zooplankton in marine fronts. He was member of the National Council of Scientific of Scientific Research and Technology (CONICET); and director of the Fisheries Ecology Project (INIDEP). He taught a variety of courses in Universities of Argentina and of Latin America.