Water transparency in the Venice Lagoon during COVID-19 lockdown revealed by Copernicus Sentinel-2 satellites

A paper entitled “COVID-19 lockdown measures reveal human impact on water transparency in the Venice Lagoon” has been recently published by a team of researchers from the Institute of Geosciences and Earth Resources (CNR-IGG) and the Institute of Marine Sciences (CNR-ISMAR). The article discusses the environmental changes related to the COVID-19 lockdown in Venice and analyzes the different factors that affected turbidity in the lagoon waters.

These include: the drastic reduction of wake waves that followed the decrease of water traffic in the lagoon and city canals, the absence of precipitation on the drainage basin, the seasonality of the growing cycle of phytoplankton and the absence of wind waves. In this particular period, the lack of the touristic pressure also halved the amount of wastewater discharges in the historic center.

Satellite images of the European Copernicus Programme revealed the main changes occurring in the Venice Lagoon once emptied of the usual array of motorboat taxis, transport and tourist boats which normally clog the canals. Following the reduction of water traffic, turbidity decreased around the city and along the more critical routes within the lagoon, like the canals connecting Venice to the airport and the other islands. At the same time, the satellite images showed the impacts determined by essential activities, that continued throughout the lockdown, as clam harvesting on tidal flats and the transit of commercial ships in the industrial channel Malamocco-Marghera.

The absence of one of the main anthropic disturbances on the lagoon environment provided a unique opportunity to observe the natural processes controlling the lagoon water quality and to emphasize the impact of human activity in coastal ecosystems. The high water transparency, reported by the media and quantified by this study, is considered an ephemeral condition related to the combination of natural seasonal factors and the effects of COVID-19 restrictions. 

Reference: Braga, F., Scarpa, G. M., Brando, V. E., Manfè, G., & Zaggia, L. (2020). COVID-19 lockdown measures reveal human impact on water transparency in the Venice Lagoon. Science of The Total Environment, 139612. https://doi.org/10.1016/j.scitotenv.2020.139612

Paper is available here: https://www.sciencedirect.com/science/article/pii/S0048969720331326

For further information, please contact: Luca Zaggia, CNR-IGG (luca.zaggia(at)igg.cnr(dot)it).