The coast guard keeps an eye on the sea

Coast guard

Impressive Noctiluca (Sea Sparkle) bloom in the North Sea

The past weekend, striking orange spots and strings were observed in the Belgian part of the North Sea near the Buitenratel sandbank. A sailor reported this to the Coast Guard centre (through the Maritime Rescue and Coordination Centre - MRCC) as a possible pollution. After inspection by various coast guard partners, Maritime and River Police, ministry of Defence and the Management Unit of the North Sea Mathematical Models (MUMM, it became clear that this was an unseen bloom of the single-celled plankton species ‘Sea Sparkle’. The warm and calm weather of the past few days is probably an important explanatory factor. The mass is already rotting, which could possibly lead to oxygen deficiency and fish mortality. It is also possible that the remains will be washed ashore on Belgian beaches during this week.

We cannot be sure that this will be the case. However, should the noctiluca wash ashore, this will be not be in one particular spot, but scattered along the whole coast since these are living organisms and the wind can change direction. We have no knowledge about distinctive foam patterns as was the case this spring with the algal blooms (ofPhaeocystis) and the tragic incident in Scheveningen in which five surfers lost their lives. These are a different sort of plankton.
Apart from some odour nuisance of rotting Noctiluca, there is no risk for bathers, swimmers or watersports enthusiasts. It is a harmless species, which will disappear of its own accord in time.