With the advent of deep submergence research vessels (DSRVs) biological and ecological studies of ocean deeps have made great strides. Especially these submersibles allowed to conduct physiological and biochemical experiments on benthic fauna directly on the bottom or on board with alive retrieved animals. A second great interest is the possibility to work in chaotic areas and on microenvironments. Without DSRVs most of measurements and observations obtained on hydrothermals vents would had been impossible. We will present the different equipment designed for the two French DSRVs used during the cruises conducted by the Departement "Environnement Profond" de l'IFREMER to study hydrothermal and "normal" deep-sea ecosystems. We will discuss the new devices required to progress especially in knowledge of physicochemical properties of micro-environments and the interest to use remotely operated tethered unmanned vehicles (ROV) instead of DSRVs.