In this study, we present a framework for seagrass habitat mapping in shallow (5–50 m) and very shallow water (0–5 m) by combining acoustic, optical data and Object-based Image classification. The combination of satellite multispectral images-acquired from 2017 to 2019, together with Unmanned Aerial Vehicle (UAV) photomosaic maps, high-resolution multibeam bathymetry/backscatter and underwater photogrammetry data, provided insights on the short-term characterization and distribution of Posidonia oceanica (L.) Delile, 1813 meadows in the Calabrian Tyrrhenian Sea. We used a supervised Object-based Image Analysis (OBIA) processing and classification technique to create a high-resolution thematic distribution map of P. oceanica meadows from multibeam bathymetry, backscatter data, drone photogrammetry and multispectral images that can be used as a model for classification of marine and coastal areas. As a part of this work, within the SIC CARLIT project, a field application was carried out in a Site of Community Importance (SCI) on Cirella Island in Calabria (Italy); different multiscale mapping techniques have been performed and integrated: the optical and acoustic data were processed and classified by different OBIA algorithms, i.e., k-Nearest Neighbors’ algorithm (k-NN), Random Tree algorithm (RT) and Decision Tree algorithm (DT). These acoustic and optical data combinations were shown to be a reliable tool to obtain high-resolution thematic maps for the preliminary characterization of seagrass habitats. These thematic maps can be used for time-lapse comparisons aimed to quantify changes in seabed coverage, such as those caused by anthropogenic impacts (e.g., trawl fishing activities and boat anchoring) to assess the blue carbon sinks and might be useful for future seagrass habitats conservation strategies.

Among the activities planned for the MUSAS Project, the digital reconstruction of the underwater sites constitutes a particular challenge, requiring strong cooperation between archaeologists and technicians. The case of the Villa dei Pisoni in Baiae, one of the richest in the Phlaegrean territory, is particularly interesting: the architectural remains, already documented in the 1980s and now inserted in one of the diving spots of the Underwater Park of Baiae, are disseminated on a huge surface, including quays, thermal complexes, a fishpond, and a large, luxurious viridarium. The effort required for the digital reconstruction of the ancient villa improved the previous knowledge and the lack of documentation even in a well-known site. In this paper, we will retrace the long path from the 3D reconstruction of the archaeological remains to the virtual architectural model of the villa, the numerous challenges, doubts, and uncertainties in the creation of the original spaces, and the support offered by the ancient sources, both literary and iconographic, in solving archaeological problems.

Underwater cultural heritage (UCH) is a crucial asset for our knowledge of human history and traditions

Underwater cultural heritage (UCH) is one of the richest and most vulnerable records of humankind’s past