Progress report for
Achievement at a glance
Since the immersion of the artificial reefs printed with a 3D printer in the marine protected area of Larvotto (Monaco), several research programs have been launched, in line with the natural laboratory vocation of this MPA implanted in a highly urbanized environment. These researches concerns (i) the study of the biofilm and the macrofouling which develop on the substrate, (ii) the development of a method of automatic counting of fish assemblages installed in and around the artificial reefs, (iii) the evaluation of the three-dimensional complexity of the AR, (iv) the use of photogrammetry to evaluate this 3D complexity and (v) the use of a submersible hyperspectral camera. These researches are led by the ECOSEAS laboratory, previously ECOMERS (CNRS & University of the Cte d\'Azur, Nice, France), in collaboration with BOREA laboratory (CNRS, MNHN), CREOCEAN company, and PlanBlue company.
Beneficiaries
The main vocation of the Larvotto MPA is to provide to researchers a natural laboratory where they can carry out scientific studies in the best conditions. Most of these researches aim to provide practicable deliverables allowing management issues. Consequently, the main beneficiaries are the managers: in first, the manager of the Larvotto MPA and thanks to her the other managers of the Mediterranean MPAs through the MEDPAN network. In addition, through the international publications, the others beneficiaries are the academic population.
Actions
Biofilm: its quality and richness determine the subsequent colonization by macrofouling. The objective is to determine the link between them and the substrate by comparing colonization on different samples (Dolomite sand, natural rock and concrete, the product normally used to build ARs).\r\nFish counts: Monitoring of fish fauna in and around 3D ARs is classically carried out by underwater visual census. The automatic tracking technique we are developing involves cameras placed near the reefs and left at the bottom of the water for 7 to 8 hours, taking a picture every 30 seconds. It may be an interesting technique to provide a monitoring standard.\r\nThree-dimensional complexity: To accurately assess the 3D complexity of ARs will allow to compare the complexity of the new 3D ARs with that of natural substrates. The results will be compared with more conventional technique as the fractal dimension. The aim is to establish a link between the complexity and the species abundance, showing that an increase in 3D complexity leads to a biodiversity increase.\r\nPhotogrammetry: This technique allows to develop a 3D model as close as possible to reality. We are testing if these models allow to assess the indices we developed (above) to calculate the 3D complexity.\r\nSubmersible hyperspectral camera: This camera scours the seabed using hyperspectral imagery, combining imaging and spectroscopy where each image is taken for a narrow band of the electromagnetic spectrum. Each species has a particular hyperspectral image. The development of a submersible camera allows to acquire underwater images and to quickly have a precise identification of the species present or to measure the spectral diversity, which could then serve as a proxy for specific diversity, a parameter widely used in benthic ecology, but often difficult to assess in situ.
