Norwegian Fjord Sea Sparkle (Morild)

Along Norway's southern and western coast, blooms of the bioluminescent dinoflagellate Noctiluca scintillans turn the sea into a light show the Norwegians call "morild." By day a dense bloom stains sheltered bays a reddish-brown, almost chocolate colour; after dark, any disturbance — a breaking wave, a dipped oar, a hand or a dragged stick — makes the water erupt in cold blue-white flashes as the cells fire their luciferin-luciferase reaction.

The bloom itself can run from summer into autumn, but here is the catch that sets Norway apart: through midsummer the high-latitude sky never goes dark (white nights and, farther north, the midnight sun), so the glow is invisible no matter how strong the bloom.

The display only becomes watchable once true night returns — roughly late August through October — on a dark, moonless, calm night in a wind-sheltered bay.

Marine biologists at the Institute of Marine Research track these blooms from the outer Oslofjord and Hvaler in the south up the Skagerrak coast and as far north as Øygarden near Bergen.

Where to see it

A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.