Just like a steady snowfall, tiny organic particles – dead plankton and smaller organisms as well as their fecal products, but also sand, dust and soot – sink from the water surface to the sea floor. Much of this material that sticks together like snowflakes, is already consumed on its way down by microbes, zooplankton and filter feeders. In regions that are not reached by sunlight, marine snow is an important source of food.
Global climate change may disrupt this cycle: If stratification of the seawater increases due to rising temperatures, the marine snow could accumulate in one layer instead of sinking all the way down to poorly-lit depths. And since increasing acidification impairs calcification and less or lighter calcium carbonate are produced, this might also affect the sinking process. For this reason, some groups of organisms might find fewer nutrients than available under current conditions.