We thought 2020 was weird enough, but then we saw the Sentosa South Cove waterway turn a pinkpish-purple on 12 Jan this year.
Residents must have thought their reality had been photoshopped by some magical being, but the sight was real.
That wasn’t the only odd thing people noticed in the waterway.
Dead Fish & Sewage-Like Smell
It all started on 5 Jan 2021, when residents in the area noticed a sewage-like smell emanating from the waterway.
Either a giant had taken a poop in the waters, or something weird was going on.
Then, as the smell grew stronger, dead fish started appearing at the banks of the waterway.
Rabbitfish, moonyfish, batfish and leatherjacket fish were identified among the carcasses.
A large-scale clean up at the waterway took place on 9 Jan 2021 and on 11 Jan 2021, the Sentosa Cove Resort Management (SCRM) informed residents that both the dead fish and foul smell was gone.
Everything should have been fine and dandy from there, right? Except the whole waterway turned pinkish-purple the next day.
Netizens came up with all sorts of theories as to what caused the change in colour, but now we have a concrete explanation.
Heavy Rain to Blame
Investigations have revealed that heavy and persistent rainfall in recent weeks had altered water conditions, leading to the strange smell and sight at the waterway.
In a joint statement on Sunday (17 Jan), the Sentosa Development Corporation (SDC) and National Environment Agency (NEA) also explained why so many dead fish washed up on the banks of the waterway.
Water samples showed that the waterway had low levels of salinity and dissolved oxygen, which may have led to the death of the many fish spotted.
As to what changed the colour, we have an algal bloom to thank.
An algal bloom is a rapid increase in the population of algae in freshwater or marine water systems, and is often recognized by the discolouration in the water from their pigments.
The authorities came to this conclusion as they found high amounts of pico-cyanobacteria – a form of algae – in the water samples.
The colour of the bloom will depend on the species of algae, as they can show up in many different colours such as green, brown, red, or pink.
While one explanation for the dead fish is a low level of oxygen in the water, the irritation caused by the algal bloom could also be to blame.
And these dead fish were the cause of the foul, sewage-like smell, as their carcasses were decomposing.
The authorities said they would continue to monitor the quality of waters in the waterway.
In the meantime, residents are advised to refrain from water sport activities there.
Though I’m sure they weren’t dying to dive into waters recently patronised by so many rotting carcasses.
Heavy rain is a rather boring explanation, but it’s the conclusion the authorities have come to.
Join us next week for another episode of You Think That Was Weird? Check This Out.
Featured Image: Facebook (The Heron Of The Green Barrel)