Algae Blooms at Narrabeen

Does This Mean Bioluminescence on Northern Beaches?

More on Dee Why

Sometimes on the beaches at Dee Why, you might notice blankets of red resting on the top of the breaks. These are algae blooms, a rapid and excessive growth of algae, typically fuelled by an excess of nutrients in the water (primarily nitrogen and phosphorus).

Algae blooms can vary in colour, from green to brown, red, or even blue, and they often create dense mats or scums on the water's surface. Some algae species produce toxins that are harmful to aquatic organisms and can pose risks to human health, so maybe avoid going for a dip when you see a red sea!

Algae Blooms and Bioluminescence

Algae blooms aren't all bad news, because they can signal the presence of organisms capable of Bioluminescence. This is the fascinating natural phenomenon where living organisms produce light through a chemical reaction.

These light emissions are primarily caused by the presence of specific molecules called luciferins, which react with oxygen and enzymes called luciferases, resulting in the release of energy in the form of light. When these bioluminescent algae are disturbed, such as by the movement of water or physical contact, they can emit light, creating a shimmering or glowing effect in the water.

It's believed this reaction is primarily used as a defence mechanism, with sudden burst of light creating a distraction or confusing potential predators. Some deep-sea creatures also use bioluminescence to camouflage themselves by matching the intensity and color of light coming from the surface above, rendering them virtually invisible - clever huh!

Just remember, Algae blooms can consist of a wide variety of algae species, and bioluminescence is a specific adaptation found in certain types of algae. So, while algae blooms and bioluminescence can be connected, the presence of an algae bloom doesn't necessarily guarantee bioluminescence.

However, if you've spotted an algae bloom and want to try your luck, we recommend:

• Heading down to the waters edge well after sundown - you want it to be as dark as possible. A moonless night? Perfect.

• Avoid areas with lots of light pollution.

• Warm water temperatures can create better reactions.

Happy bioluminescence hunting!

MORE ON DEE WHY