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Venice canals are clear enough to see fish as coronavirus halts tourism in the city

Swans have returned to the canals and dolphins have been spotted in the port.

The coronavirus pandemic has had an unexpected side effect in Venice, where the normally cloudy canals have transformed into water crystal clear enough to see fish swimming below.

Swans were seen in the water, while dolphins have been spotted swimming in the port.

However, the transparent water isn't so much a sign of better water quality as it is the result of the lack of boat traffic, which typically kicks sediment to the surface, Pierpaolo Campostrini, the managing director for the Consortium for Managing Scientific Research on Venice Lagoon System, told ABC News via email.

"The low turbidity of the water does not mean cleanliness," Campostrini said. "The transparency is due to the absence of sediment resuspension."

The cold temperature of the water also plays a part, Campostrini said. At about 57 degrees Fahrenheit, there is little synthesis of organic compounds from carbon dioxide, which doesn't begin until about 62 degrees Fahrenheit.

It's likely that the air quality has improved since "every kind of pollutants decreased a lot," but a chemical analysis would need to be performed to say so for sure, Campostrini added.

Amid the crisis, the clear water is a small reprieve for Venice, which just months ago experienced flooding by the highest tide in more than 50 years, causing inestimable damage to the centuries-old city.

More than 35,000 coronavirus cases have been confirmed across Italy, the second-highest national total behind China, according to data compiled by Johns Hopkins University's Center for Systems Science and Engineering.

Medical facilities in Northern Italy's hard-hit Lombardy region will soon be unable to help the sick, regional governor Attilio Fontana said Wednesday.

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