Photogrammetry, Optical SEnsors, and unmanned underwater vehIcles for noninvasive large-scale monitoring of meDiterranean benthic cOmmuNities and habitats

The Mediterranean benthic communities are facing both anthropogenic pressures and biogeochemical disturbances. International guidelines pursue the importance of preserving benthic environments, where a wide number of habitat-forming species is currently threatened. Monitoring provides essential information for mapping the ecological status of underwater environments and quantifying the impact of global changes on marine species. Detecting the health status of endangered species demands a high degree of accuracy and fine-scale resolution. Moreover, largescale mapping and monitoring activities require significant efforts in data collection, hardly sustained without taking advantage of using underwater remotely operated vehicles (UROVs). The main goal of the project lies in improving, testing and validating in the open water through an underwater drone a multi-parameter measuring system based on the integration of photogrammetry and fluorescence imagery. The innovative system was developed in a previous research project, named “SIMBAD - Sistemi Innovativi di rilievo per il Monitoraggio ambientale e la ricostruzione 3D di organismi Biocostruttori mArini con Droni subacquei” (FAR2020 “Mission Oriented” funds). Within SIMBAD, the system was implemented with an RGB camera and optical filters for capturing the fluorescence intensity signal. The combination was tested in laboratory, both in dry and wet environments through a 950 L recirculating seawater aquarium system with multiple tanks and controlled conditions, hosting samples of organisms mainly retrieved from fisherman by-catch. The SIMBAD project also allowed to buy a marine drone (the BlueRov2 of Blue Robotics) and to design and physically build a special device for mounting the measuring system on its bottom. If SIMBAD significantly contributed to increasing the hard skills of the team members and producing the basic elements of the system, with POSEIDON the research group will finalize the efforts spent by physically integrating the measuring system onboard of the already bought UROV and testing the overall system in the open water. In this way, we will foster the automation of the image collection process, increasing the amount and the quality of data and enabling large-scale investigations and more effective results than traditional in-situ measurements. High-resolution surveys indeed, will allow the development of novel digital analysis, such as the assessment of the health status of the species at a fine-scale using fluorescence high-resolution 3D models. The combination of both datasets will allow the non-destructive extraction of relevant biometric quantities from benthic communities. POSEIDON experiences the benefits of combining emerging techniques (that can be applied to a range of 3D morphometrics, different habitats and species) and paves the way to innovative procedures and methods in ecological research, fostering the targets of the European Green Deal and EU Biodiversity strategy.