But don’t worry, it should be back to its turquoise hue soon.

If you’ve been paddling in the waters around Jumeirah recently, in some patches, you might have noticed a distinctive change in the colour of the sea.

Dubai Municipality has shared a photo of the phenomenon to its social media accounts, which shows the usually-pristine waters in the area looking unpleasantly murky.

There is, however, an explanation. The municipal body said its Environment Department has carried out testing, and found the discolouration was caused by a type of algal bloom called Trichodesmium erythraeum.

Dubai Municipality said the bloom “is not harmful and will fade in the coming days”.

So, what is this stuff? Trichodesmium erythraeum – also known as sea sawdust – is common in tropical and subtropical ocean waters all over the world.

We checked in with UK-based plankton scientist Dr Richard Kirby, aka the Plankton Pundit, who said it typically blooms in “nutrient-poor, stable (calm) waters, where there is a thermocline near to the surface”.

It is perhaps best known for blooming in the Red Sea, giving the water its famous reddish-brown colour (and consequently, its name).

In some conditions, the blooms can release a toxin – though the concentration in the ocean is not thought to be high enough pose a health risk to humans, according to this fact sheet from the city of Gold Coast, Australia website. They are also supposed to disappear after a few days.

In the meantime, it is best to avoid affected areas – and if you do come into contact with the blooms, make sure to rinse them off your skin, just to be safe.

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