There is snow beneath the waves, but you do not need freezing temperatures to make it. “Marine snow” is the name for a remarkably important fall of tiny particles through the ocean.
What is falling?
Near the surface, plankton live, grow and die. Along with other fragments of organic material, waste and small grains of sediment, their remains begin to sink. As they drift downward, bits can clump together into pale flakes that look like snowfall in the water.
An incredibly slow journey
Some of this material travels through the water column for weeks before it reaches the seabed. National Oceanic and Atmospheric Administration (NOAA) explainers describe a shower made of biological remains as well as other particles, including sediment and dust.
Food in the dark
The deepest parts of the ocean cannot rely on sunlight-powered photosynthesis in the way surface waters can. Marine snow carries carbon and nutrients downward. Many deep-sea animals filter it from the water or eat it after it settles, making the drifting material part of a vast ocean food system.
Why it is extraordinary
The process is quiet and easy to overlook, but it links the sunlit surface to life thousands of metres below. Something that looks like underwater dust helps support entire communities in darkness.
This is an original explainer based on sources linked below. The image is stylised graphic artwork, not a documentary photograph. How we verify stories.