Vulnerability of tidal morphologies to relative sea-level rise in the Venice Lagoon

The rise in sea level and land subsidence are seriously threatening the diversity of tidal morphologies that have made the Venice Lagoon such a distinctive landscape. Here, we assess the vulnerability of tidal morphologies to relative sea-level rise based on a new conceptual framework that accounts for both above- and below-sea-level zones, sedimentary architecture, and surface morphology. Around 80 % of the lagoon area will face moderate to severe vulnerability by 2050, doubling compared to the 1990s. While the subtidal zone may be relatively less threatened compared to past conditions, the drastic decline in intertidal morphologies is alarming. This contributes to the flattening and deepening of the lagoon topography and thus to the loss of lagoon landscape diversity, likely leading to a decrease in the ecosystem services the tidal morphologies provide. The interconnection of intertidal and subtidal morphologies is crucial for maintaining the overall health and functionality of the lagoon's ecosystem. Any disruption to one aspect can have ripple effects throughout the entire system.