Seafloor morphology and habitats of tidal channels in the Venice Lagoon, Italy tidal channel habitats

Coastal lagoons are among the most vulnerable and economically important ecosystems on Earth and tidal channels are crucial for their functioning since they allow the exchange of water, sediments, nutrients, biota, and pollutants with the open sea. Despite their importance, there have been very few studies concerning their seafloor morphology and associated benthic habitats. Here we present the results of the high-resolution multibeam echosounder survey and ground truth sampling carried out in 2013 and in the following years to map in detail the main substrate characteristics. With unprecedented detail we highlight previously undocumented coastal wetland geomorphic features and benthic communities in coastal wetlands, describing their surrogacy. The substrate type and depth appear to influence the occurrence of distinct benthic biota. Overall, the tidal channel habitat described in our case study is in good condition and in a stable trend assessed with medium confidence.