“Sea snow (marine snow) is the ocean’s slow-motion snowfall, not ice, but tiny flakes of organic bits drifting down from the surface: dead plankton, mucus, dust, and yes… a fair amount of poop pellets. 😄 It’s a big deal because it feeds deep-sea critters and helps move carbon into the deep ocean. In vampire squid territory, it’s basically dinner falling from above.”

What is Sea Snow? The Deep Sea’s Falling Feast
Sea snow (also called marine snow) is a gentle blizzard of tiny particles that drifts from the ocean’s bright surface down into the deep. It looks like underwater snowflakes, but it’s not frozen water. It’s a mix of biological crumbs: dead or dying plankton, microscopic algae, bits of shells, dust, and sticky mucus that causes particles to clump together. Along the way, animals and microbes nibble it, repackage it, and sometimes turn it into faster-sinking pellets. National Ocean Service+2MBARI+2

Think of it as the deep ocean’s food delivery system. Sunlight powers life near the surface, but deep-sea creatures live in darkness, far from photosynthesis. Sea snow is one of the main ways energy makes that journey downward. For many animals, it’s an everyday meal: a steady rain of nutrients that keeps the twilight zone and abyss from going fully empty. NOAA Ocean Exploration+2MBARI+2

It’s also important for the planet. As sea snow sinks, it carries carbon away from the surface. Some of that carbon gets recycled on the way down, but some reaches deeper waters and sediments, becoming part of the ocean’s long-term carbon storage story. MBARI+2Scientific American+2

Pocket Fact: Some sea-snow flakes can drift for weeks before they finally settle on the seafloor.