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Marine Snow – not the same wonderland we know

Considering the Christmas season, one comes to thinking about winter and the snow it brings. For me the marine version comes to mind. This phenomenon happens at most depth levels in the water column. Nevertheless, it is especially important to the inhabitants of the deep sea. Marine snow is not frozen water particles that falls from high altitudes into a white fluffy sheets of ice. We know salt water does not react the same ways fresh water does. So what is marine snow?

By Olivia Islas

December 4, 2023


Marine snow are particle aggregates consisting of different types of organic and inorganic debris. It comes from the degrading waste as it gently sinks to the seafloor. The particular biomass of marine snow varies by region and season. It can be made up of dead algae, dead plants, fecal matter, deceased animals, and other debris. I suppose, this sounds disgusting, but it is no less beautiful in the ocean.

Analysis of these particles can be difficult especially at extreme depths. Though you make see it around coral reefs, whale falls, and other places teeming with life. Alternatively, at depths where visible life is sparse, marine snow is like a heavenly feast for many filter feeding creatures. It provides all or most of what they need to survive like for example carbon. It shows the interconnected nature of the ocean because whatever happens in the epipelagic, or sunlight zone effects the bathypelagic, or midnight zone.

The giant larvacean, or bathochoraeus stygius is a filter feeder of marine snow. It is very small in size, yet filters large amounts of sea water in a water column in a matter of days. The debris from this filtration gets stuck in the larvacean's large mucus house. Periodically, this house is discarded for the larvacean to make a new one and the remains degrade and sink to greater depths once again becoming marine snow.

Vampire Squid Image credit to Monterey Bay Aquarium

The marine snow's composition has changed; however, it’s now become food for the vampire squid vampyroteuthis inernalis. It may look like a terrifying octopus, but this gelatinous cephalopod has its one subcategory because it's not quite a squid or octopus. These interesting creatures float in a low oxygen, high pressure zone (2,000-3,000 ft.) where there is virtually no life-giving nutrients or conditions. Vampire squids depend entirely on the marine snow to survive. Despite its appearance, they have few defense mechanisms, so they prefer to dwell in the zones where predators are few. What defense mechanisms they do have are squirting bioluminescent fluid and using its jet propulsion to escape. Those teeth serve to intimidate when it folds itself up, but they are used mostly to filter marine snow. These are only a couple of the numerous creatures in the lower depths that thrive of off the nutritious snow from above.

Let it snow!

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