On calm winter and spring nights along the coast of Oman, residents and visitors alike are often captivated by a surreal sight — gentle blue waves shimmering with an ethereal glow. This dazzling marine light show, known as bioluminescence, is caused by microscopic organisms called Noctiluca scintillans. But while these glowing creatures enchant the eye, they also harbour a less visible, far more troubling story.
Noctiluca scintillans, a species of dinoflagellate, has become one of the most dominant forms of microalgae in the Sea of Oman. These tiny organisms are technically animal-like, but they form a unique partnership with photosynthetic green algae, enabling them to harness energy from the sun. Their blooms are linked to seasonal monsoons: the chilly Northeast Monsoon and the nutrient-rich upwellings brought by the Southwest Monsoon. Both events trigger conditions ripe for Noctiluca’s explosive growth.
And therein lies the problem.
When these blooms reach massive densities — a phenomenon known as a harmful algal bloom (HAB) — they pose serious ecological and economic risks. “Noctiluca blooms deplete oxygen in the water, creating hypoxic conditions that suffocate marine life,” explains Dr Khalid al Hashmi, a marine scientist at Sultan Qaboos University (SQU). “They also release ammonia, which is toxic to fish and other organisms.”
The consequences ripple beyond marine ecosystems. For Oman’s vital fisheries and aquaculture sectors, Noctiluca blooms can mean fish kills and ruined harvests. Coastal desalination plants — essential for producing drinking water — also suffer. The microalgae clog the reverse osmosis membranes, reducing efficiency and increasing operational costs.
To tackle the growing threat, a team of scientists from SQU, led by Professor Sergey Dobretsov, UNESCO Chair in Marine Biotechnology, has launched a major research initiative called FORCA-HAB. Funded by the Ministry of Higher Education, Research, and Innovation, the project aims to understand the origins, movement, and impact of Noctiluca blooms along northern Oman’s coast.
One area of focus is the connection between bloom density and the phenomenon of bioluminescence. Hajir al Lawati, a researcher with SQU’s Department of Marine Science and Fisheries, is studying how Noctiluca cells emit light when disturbed by waves or water movement. “The brighter the glow, the denser the bloom,” she notes, emphasising that this natural wonder also serves as a warning signal.
To detect and monitor these blooms beneath the surface — where they often escape satellites and aerial drones — Dr Gerd Bruss deploys sea gliders, unmanned underwater vehicles capable of diving up to 1,000 metres. Equipped with high-tech sensors measuring temperature, salinity, oxygen, and chlorophyll, these gliders help researchers locate blooms as deep as 20–30 metres.
Meanwhile, the microbiological side of the puzzle is being tackled by MSc student Buthaina al Khaziri. Under Professor Dobretsov’s supervision, she has isolated 82 species of bacteria from seawater collected during blooms. Advanced DNA sequencing revealed that certain bacteria actually boost the growth of Noctiluca, while others — including potentially pathogenic species — may contribute to fish mortality.
“This kind of detailed genetic insight gives us a fuller picture of what’s really happening during a bloom,” says Al Khaziri. “It’s not just the algae — it’s an entire ecosystem of interactions, some of which are still poorly understood.”
Ultimately, the scientists hope their work will pave the way for predicting and mitigating future harmful algal blooms in Oman. As climate change and coastal development continue to alter marine environments, understanding and managing these complex phenomena has never been more urgent.
The shimmering waters of the Sea of Oman may still dazzle tourists, but behind the beauty lies a powerful reminder: nature’s most mesmerising spectacles can also be its most dangerous warnings.
Quick Facts: Noctiluca Blooms in Oman
What is Noctiluca scintillans?
A species of bioluminescent dinoflagellate — a microscopic marine organism that glows when disturbed by water movement.
Why does it bloom in Oman?
Seasonal monsoons enrich coastal waters with nutrients, triggering large-scale growth of Noctiluca.
What’s the risk?
Hypoxia: Dense blooms deplete oxygen in the water, threatening marine life.
Toxicity: They release ammonia, which can cause fish kills.
Industry impact: Desalination plants suffer from clogged membranes; fisheries face stock losses.
Where are blooms found?
Surface and subsurface waters — often 20–30 metres deep — especially along northern Omani coasts.
Note: Images are for illustration only.
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