The research line on marine invertebrates of the “Benthic Biology and Ecology Research Group” is formed by Associate Professors of the Animal Biology Department of the University of Barcelona and Researchers of the Centre of Advanced Studies of Blanes (Spanish Research Council, CSIC). The main groups studied are echinoids, opistobranchs, and ascidians, as well as meiofaunal groups in general. Our approach is focused on the biology, interactions, and population dynamics of the different groups, but we seek to keep a global perspective of the function of the whole ecosystem.