When I took a leasurely walk this morning I admired the beautiful snow capped peaks of the mountains all around. This time of year people either talk about how they are glad that the snow is not yet impacting traffic or they wish for the fluffy stuff in anticipation of time spent crunching through a white wonderland, skiing, sledding, building snow figures or digging tunnels and piles. Scientifically, snow is nothing more than rain forced into its crystalline form by low temperatures in the clouds and the air it falls through.
There is a snow that is not made out of water, but falls in the water: it is called marine snow. Like real snow marine snow is also a seasonal occurrence, but it is most commonly associated with seasons of high surface water productivity. Marine snow is composed of various chunks and pieces of marine algae and pieces of dead plankton animals, as well as their fecal matter clumped together to form the “snowflakes” which, because of their size and density start sinking to the bottom. Some phytoplankton, plant-like photosynthetic cells that live near the sunlit surface and some of the gelatinous zooplankton organisms like salps and jellies secrete a sugary mucus, that provides the glue to form the marine snow. Seen under the microscope marine snow looks like the ocean’s equivalent of dust bunnies: everything from dirt particles, hairs, antennae, pieces of the discarded exoskeletons of various small crustaceans, pieces of diatoms and seaweeds, dust and any plant pollen that the wind may have carried onto the ocean.
This description of marine snow reminds me very much of the stuff that sticks to the sponge when I clean around the house: everything that exists only for the purpose of being cleaned and washed away. Nature of course has much better ways of dealing with the ocean’s dust bunnies and nothing is ever wasted. Marine snow is actually the food base for a multitude of organisms that live in the largest ecosystem we have on earth: the abyssal plains, the vast expanses of deep sea floor that stretch along most of the ocean’s basins. There, where sunlight never reaches, food is scarce. For many years, we thought that there could not be any life in those dark and inhospitable environments. However, the more we learn about the deep sea the more life forms we find. For many of those bottom dwellers the table gets set when the marine snow begins to fall. Packed with organic sugars and proteins, and spicked with bacteria marine snow provides sustenance for animals living in and on the bottom sediment.
When I was in College in Germany I had a summer job as a research diver assisting in marine collections and miscellaneous underwater projects for a Biological Station in the North Sea. I remember one assignment with a film crew that came to film marine snow and study it. Today, I can just read about it on Wikipedia or a more sophisticated government website, but it is kind of cool to remember when researchers were still puzzled by the phenomenon and needed to go to great length to learn about it all.
Let the bottom dwellers in the ocean wait for marine snow to gain a few calories to get them through the winter. In the meantime I will wait for the white crystals, so I can get out my skis, burn off some calories and enjoy the invigorating cool fluff.