Sea spark spotting on the Wadden Islands

Maybe you've experienced it: a warm evening, a quiet beach and then suddenly you see blue light in the surf. The water seems to light up as you walk through it and sometimes your footsteps remain visible for a while in a luminous haze. This phenomenon is caused by sea sparkle: a tiny organism that responds to movement by giving off light. But what exactly is sea spark? Why does it light up? And when are you most likely to see it?

What is sea spark?

If you have ever seen sea sparkle, you know how special it can be. The water lights up blue and with every wave or movement, it looks like glitter appears in the sea. That effect is caused by sea sparkle: a single-celled organism that lights up as soon as the water is disturbed.

Sea sparkle is officially not a real algae or animal, but a separate type of unicellular organism with the Latin name Noctiluca scintillans – which literally means ‘flashing night light’. Under the microscope, it looks a bit like a balloon with a tail, with which it moves through the water, eating plankton and larvae along the way. Sea sparkle itself is food for shrimps, for example.

These are the ideal conditions for spotting sea sparkle

If conditions are right, algae can multiply quickly. Sometimes you can then already see an orange-brown haze in the water during the day. But it is only when it is dark that the phenomenon really becomes visible: the sea then seems to light up with every wave or footstep.

The Wadden Islands are ideally suited to see sea sparkle. The water there is shallow, the beaches are wide and calm and there is little artificial light. Still, sea sparkle is a natural phenomenon that is difficult to predict. There are a number of conditions that increase the chances:

Warm days

Sea spark grows well at higher temperatures. After a few warm, summer days (25°C or more), the chances increase. Especially if it also ’s remaining mild at night, conditions are favourable.

Little wind

Wind creates turbulent water and disperses algae. In calm or windless weather, they can accumulate along the shore, in shallow areas where you can see it well. So a day with little to no wind is ideal.

Dark nights

Light pollution or a full moon makes sea sparkle less visible. The best effect is seen on dark, clear nights without moonlight. A new moon or clouds shielding the moonlight helps.

Unmoved water

Sea sparkle shows up best in calm water. In calm seas, the algae stay closer together and you can see the glow better. Wide sandy beaches with shallow water are therefore ideal.

Season

In the Netherlands, sea sparkle is usually observed between May and August. June and July are the months when it is most often reported. Outside that period, the probability is lower, but not excluded.

Tips for capturing sea sparkle

Sea spark is not only beautiful to see, but also special to capture – although it does take some practice. Sea spark is only visible when the water is moving. Therefore, walk slowly through the shallow water, throw a small stone or watch the surf carefully. Even gently moving your hand through the tide line can be enough to make the glow appear.

Be patient and give your eyes time to get used to the dark. Avoid bright light from phones or torches, as it makes it harder to see the sea spark. Sometimes it takes a while, but with a little rest and attention, chances are you will notice something special.

Photographing sea spark

See spark photography is tricky, but certainly not impossible. Use a camera with manual settings and a tripod.

Set the shutter speed to 5 to 30 seconds
Use a high ISO (1600–3200)
Focus on a point of light in the distance or manually on the surf

With a smartphone you are more likely to have an app that allows you to set shutter speed and ISO yourself.

Why are the Wadden Islands suitable for spotting sea sparks?

The Wadden Islands are one of the best places in the Netherlands to see sea sparks. This is mainly because of the tranquillity and space. The beaches are vast and often free of artificial light. In many places, there are no buildings nearby, making it really dark as soon as the sun goes down. This makes it much easier to observe the subtle glow of sea sparkle. The water along the wadden coast also plays a role. It is often shallow and calm, which favours the accumulation of sea sparkle in the tide line. In crowded places or with strong currents, the algae spread faster and the effect is harder to see. Here, on the islands, there is less disturbance from shipping or other crowds.

In addition, on the Wadden Islands you have an unobstructed view of the sea. There are no tall buildings or bright light sources in the way. That makes watching sea sparkle – if there is – extra impressive. You see it not only under your feet, but sometimes over dozens of metres along the surf.

All these factors combine to make an evening on the beach suddenly a very special experience.

Want to see sea sparkle for yourself? Then plan a few days on one of the Wadden Islands. That way you have the peace, time én space to go out at the right time.

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Sea spark spotting on the Wadden Islands