SINGAPORE - A thick layer of algae turned the waters of Marina Bay outside the Fullerton Bay Hotel, NTUC Centre and the Promontory @ Marina Bay a rich emerald green on Tuesday (Nov 17).
Experts said a combination of hot sun and heavy rain might have caused the widespread bloom.
Dr Patrick Martin, Nanyang Technological University Earth Observatory of Singapore research fellow, said: "The heavy rain over the past couple of weeks might have caused more nutrient run-off from land, which is fuelling the bloom."
The algae bloom could have been caused by an accumulation of nutrients in the bay, washed in from rivers that drain into it, such as the Kallang River, said Mr Chan Wei Loong, programme chair of Republic Polytechnic's marine science and aquaculture diploma.
"As the weather was recently very warm, the hot sun could have caused the algae to bloom," he noted.
He said further tests would be needed to ascertain the exact cause.
"If the algae bloom continues, it could clog the gills of fish in the water and cause fish deaths. But we have seen no dead fish floating yet, so that's good," he added.
PUB said algae growth was "naturally present" in Singapore's waterways and it moves up to the water surface at night to be ready for photosynthesis at sunrise. "This is why algae are usually more visible from the early morning to the mid-afternoon."
This is not the first time algae is seen in the area.
Last month, a reader wrote in to citizen journalism site Stomp with a picture showing a similar occurrence in Marina Bay. According to the Stomp report, algae growth may be a result of high levels of carbon dioxide in the air and water.