The blob of phosphorescent* green liquid that appeared in Venice’s* Grand Canal* last weekend was caused by the chemical fluorescein.
Environmental officials confirmed the source of the discolouration after images on social media showed a bright patch of green around the famous Rialto Bridge*, near a popular dining area full of restaurants.
Fluorescein – a non-toxic* chemical – is primarily used to identify leaks in underwater building projects.
According to a CNN report, the high concentrations of fluorescein in the canal suggested it probably wasn’t the result of an accident.
Further test results are still to come and Italian police have launched an investigation into the incident.
It is the latest in a number of similar episodes in Italy in which protest groups have targeted monuments* with colours and dyes, Sky News reported.
It was only last month that environmental activists* used vegetable charcoal to turn the waters of Rome’s Trevi Fountain* black in a protest against fossil fuels, the report said, but no one has yet claimed responsibility for the latest chemical dump in Venice.
It is not the first time the city’s canals have changed colour. In I968 Argentinian artist Nicolás García Uriburu dyed the water with the same chemical used last week. Uriburu wanted to bring attention to ecological* issues and the relationship between nature and civilisation.
CLOSER TO HOME
Australia has its own bodies of water that change colour quite dramatically – although fortunately they are natural wonders and not the result of human polluters*. South Australia’s Blue Lake (Warwar) in Mount Gambier, which sits in the crater of the city’s maar volcano*, changes from blue to an intense deep turquoise blue every November until late February.
Victoria is meanwhile home to a number of astonishing pink lakes – it even has an area called Pink Lakes in the state’s largest protected park, the Murray Sunset National Park. There are four pink lakes within the park: Crosbie, Becking, Kenyon and Hardy.
The capital also has its own pink lake. Located under the Westgate Bridge in an industrial* part of Melbourne, the lake in the middle of the Westgate Park turns bright pink in certain conditions. And why pink? It’s related to the salt levels in the water.
The Parks Victoria site explains that roughly once a year, in a long enough dry spell, the water evaporates* enough to change from really salty to extremely salty. That change causes the algae* to produce pink salt-tolerant carotenoids* to survive the extreme conditions. When rain comes and dilutes* the water, the salt level drops, the algae stops producing the carotenoids and the pink colour disappears.
POLL
GLOSSARY
- phosphorescent: glowing, luminous, emitting light but no heat
- Venice: Venezia (in Italian) is the capital of northern Italy’s Veneto region, built on more than 100 small islands in a lagoon in the Adriatic Sea
- Grand Canal: the city’s main waterway, the largest and most famous of Venice’s channels
- Rialto Bridge: the oldest of the four bridges that cross the Grand Canal
- non-toxic: harmless, not poisonous or unsafe
- monuments: old buildings and structured important to a country’s history, some built to honour special people or events
- activists: people who want political or social change and takes part in activities like protests
- Trevi Fountain: Rome’s most famous fountain, it was built in the 18th Century and is considered a late Baroque masterpiece
- ecological: the relationship between living things and their environment
- polluters: person or organisation that puts harmful substances or waste into the water or air, causing damage to the environment
- maar volcano: a shallow, broad, low-relief crater blasted by a low-temperature volcanic explosion, not a volcanic cone
- industrial: relating to factories, manufacturing plants, buildings where things are made
- evaporates: converts to vapour, causing a liquid to become a gas
- algae: diverse group of aquatic organisms that have the ability to conduct photosynthesis
- carotenoids: pigments in plants, algae, and photosynthetic bacteria
- dilutes: made thinner or more liquid by adding water or some other fluid
EXTRA READING
Record floods swamp historic Venice
Dolphins dance through glowing algal bloom
Smelly theory behind the origin of Earth’s oxygen
Why do leaves change colour and fall in autumn?
QUICK QUIZ
- What is the name of the waterway in Venice where the green blob appeared?
- What is the name of the bridge nearby?
- Activists in Rome recently turned the waters of which historic structure black?
- What is the name and primary use of the chemical dumped in the water in Venice?
- What causes some of Victoria’s lakes to turn bright pink?
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CLASSROOM ACTIVITIES
1. Whodunnit?
Authorities are trying to determine who is responsible for adding the fluorescein to the Grand Canal. In the meantime, we can make some guesses about who might have done it and their motivation. Make a list of possible suspects and why they have turned the canal green.
Your ideas can range from logical suggestions to outrageous and funny ones.
Arrange your list of suspects from the most likely to the least likely to be responsible.
Time: allow 20 minutes to complete this activity
Curriculum Links: English
2. Extension
Choose the craziest suspect you thought of in your list. Write a short narrative to describe what you imagine happened.
Time: allow 30 minutes to complete this activity
Curriculum Links: English
VCOP ACTIVITY
I spy nouns
Nouns are places, names (of people and objects), and time (months or days of the week).
How many nouns can you find in the article?
Can you sort them into places, names and time?
Pick three nouns and add an adjective (describing word) to the nouns.