What are those blue glittering waves at Pasir Ris beach? Scientists explain ‘bioluminescence’

SINGAPORE — While recording a short film at Pasir Ris beach, a group of university students chanced upon something “magical”: Glowing neon blue waves crashing upon the shore, in what is known as a “luminescent algal bloom”.

One of the undergraduates, Mr Eric Teo, 24 who uploaded a video of the bioluminescent waves on Facebook on Tuesday (March 22), said: “It was really quite a sight. When you look at the sand after the waves retreat, you can see blue specks of glitter starting to retract along with the waves. And they are sparkling.

“It's like glitter in the sea.”

HOW THEY CAME TO SEE THE ‘BLUE’ WAVES

Mr Teo and four other friends were recording a short film on Sunday as part of a submission for Nustudios’ Point and Shoot, a competition where participants are given 55 hours to plan, shoot and edit a short film. 

The group of first-year undergraduates from Nanyang Technological University’s Wee Kim Wee School of Communication and Information had reached the beach at around three in the morning to shoot a scene for their film. 

Mr Teo’s friends were the first to notice the neon blue waves, and Mr Teo, who was filming at the time, immediately put his camera down to take a closer look. 

“I kind of knew about this phenomenon of bioluminescence. So I said, ‘Guys, I think we just stumbled upon something that is super rare in nature,” Mr Teo recalled.  

They were at the beach for an hour and the luminescent blooms occurred for most of the time they were there.

The “glitter” seemed to have become “dimmer” after Mr Teo returned on Monday and Tuesday, he said.

WHAT CAUSED THE WAVES TO TURN BLUE

Associate Professor Rebecca Case, a marine phytoplankton expert and principal investigator at the Singapore Centre for Environmental Life Sciences Engineering, said that the phenomenon is a form of chemical reaction. 

Dinoflagellates, a type of phytoplankton or tiny marine plants, are microscopic marine algae that drift with water currents. They produce an enzyme called luciferase, which reacts with oxygen to produce light. 

Assoc Prof Case explained: “You can only find this light where oxygen is (reacting with the algae). You see the blue light when a wave crashes on the sand because there is more oxygen available to the luciferase in that instance.

“When we swim or splash in water (or a wave crashes), seawater is mixed with oxygen. It’s this increase in oxygen that causes the luminescence.”

This is also why it does not glow all the time.

Luminescent blooms are most commonly seen along the coastline at night and Assoc Prof Case said that she has seen them off Sydney in Australia — where she used to live — in Hawaii and Cape Cod in America and on Koh Tao in Thailand.

Assoc Prof Case, who moved here in August 2020 for work, said: “I’m relatively new to Singapore and so I haven’t seen this before in Singapore. I’m looking forward to going out tomorrow (Thursday) night to sample it.”

Dr Emily Curren, a research scientist at the Tropical Marine Science Institute at the National University of Singapore, said that under suitable climatic conditions such as rainfall, salinity and temperature, dinoflagellates will reproduce rapidly and form algal blooms, leading to the “bioluminescent sighting”.  

This is because the cells are disturbed and pushed together by waves. 

Assoc Prof Case suspects that the recent monsoon season, which resulted in a long period of rain, had caused the blooms. She also believes that this phenomenon could be common in Singapore due to the high rainfall and warm weather here.

“Dinoflagellates like warmth, and it’s always warm in Singapore,” she added.

Dr Curren noted that this is not the first sighting of the bioluminescent phenomena and a similar one had occurred in 2016, when there was an unknown dinoflagellate species that bloomed along the southern coast of Singapore. 

However, she said that there is no cyclical occurrence of this phenomenon.   

IS IT SAFE TO GET NEAR THE ‘BLUE’ WAVES?

Although harmful algal blooms or “red tide” are caused by dinoflagellates, bioluminescent dinoflagellates are rarely — if ever — toxic and there is “no need to be afraid”, Assoc Prof Case said.

It is safe for people to walk on the beach and swim in the water containing these organisms, she said.

“Swimming in a luminescent bloom is simply magical — watching the water light up as your body glides through the waves should be on everyone’s bucket list,” she added.

However, Dr Curren disagreed, saying that the public “should avoid direct contact if we do not understand the organisms and their characteristics”. 

They could enjoy this natural phenomenon by looking and taking pictures from a distance instead. 

WHAT YOU SHOULD NOT DO

Though Mr Teo would like more people to witness this sight, he also hopes that Singaporeans will do their part to not disturb nature too much.

“It’s a sight that everybody should see because it’s really amazing,” he said.

“But we should make it our responsibility to keep the beach clean and not trample on the plankton. It applies to any organism that we see and not just for these,” he added. 

In his original Facebook post, Mr Teo has now added a disclaimer: “To anyone looking to go, please respect the environment, and be safe! Admire the beauty of nature, but please keep the place clean. 

“Please do not stomp on the sand like we did as it kills the poor planktons — we didn’t know what it was before.”