EMSO-LO (European Multidisciplinary See floor Observatory and water column, Western Ligurian Site) is a second generation permanent submarine observatory deployed offshore of Toulon, France. This submarine network is part of the LSPM (Laboratoire Sous-Marin Provence Méditerannée, https://www.cppm.in2p3.fr/web/fr/LSPM/index.html), close to a neutrino telescope KM3NeT (https://www.km3net.org/) which has a modular topology designed to connect up to 120 neutrino detection units.

The Earth and Sea Science (ESS) instrumentation connected to KM3NeT is based on two complementary components: an Instrumented Interface Module (MII), an autonomous mooring line (ALBATROSS) and a Scientific Junction Box (BJS, developed by Ifremer). On the ocean floor, instruments and plateforms can be connected to the BJS whose role is to supply energy and internet connection to the instruments of the site.

Among the most relevant novelties, BathyBot is an underwater robot that joined the observatory site for several years, and deployed from a structure called BathyDock. BathyBot - A benthic robot to see the invisible in the depths of the Mediterranean Sea is a remotely-operated, cabled exploration robot. It is dedicated to long-term monitoring of deep-sea environmental variables (oxygen, temperature, salinity, pressure, current - the fluorimeter data flux is available through the aquadopp data flux) as well as biology, thanks to two different cameras (images available through a citizen science project https://ocean-spy.ifremer.fr/mediterranean-spy/), various colored LEDs and a proximity imaging system (UVP-6, data available at http://ecotaxa.obs-vlfr.fr/). In particular, BathyBot will enable to see the bioluminescence emitted by marine organisms and better understand its ecological role.