Let’s imagine taking a dip at sea, to swim deeply towards the seabed and then stop to observe the water around us: we may see some small suspended dots which look a lot like our atmospheric particulate. Poetically we could see them as soft snowflakes that descend from the sky deep in the night … and it seems that this was exactly what the zoologist saw us William Beebe when he gave his name to this phenomenon. They have a harmonious name but these particles suspended in the sea are formed by far from beautiful things: Dejections, microbes and decomposition matter These are just some of the substances that make them up. Which slowly precipit to the seabed or to be eaten, are sources of nutrients for the oceans and the biodiversity, And they are very important to combat the climate change: knowing global changes we can understand How to act to contrast them.
What is marine snow?
Let’s call it as well Snow marine (Marine Snow) or, in a much less elegant way, dandruff oceanic (Ocean Dandruff): We are talking about excrement, shells, waste of dead animals or in decomposition, bacteriasuspended sediments, mucus and other particles of biological origin (both alive and dead) Produced in the most superficial layers of the sea and which slowly descend, like light snowflakes, towards the sea depths. All this and much more takes part in the formation of Sestonthe set of particles found in the water column.
This organic particulate Rich in carbon and nitrogen is not static, quite the contrary. It can vary their own size during the journey towards the seabed by changing compositionincorporating new debris and becoming heavier, being eaten and becoming source of food for marine animals. At any time and any depth the navy snow can be eaten, digested and expelled againstarting the cycle from the head.

Do animals on the bottom of the sea eat snow?
Well yes, but let’s take a step back to explain why. In the food chain a fundamental role, which often tends to underestimate, is held by light. There light regulates plant production And consequently the survival of all animals, whether they feed on vegetables or other animals. There photosynthesis But it is not obvious in the sea, on the contrary, it is a trial that are able to make only plants, algae, phytoplankton, some microbes and all those plant organisms that live in relatively low waters, where the rays of the Sun. The electromagnetic radiation of light, in fact, is unable to penetrate the whole column of water, The different wavelengths are extinct gradually going deeper and deeper, after us humans, it becomes, in essence, The most total darkness. Or rather, there is some other mechanism to produce light, but follows its own ways by bacteria and chemoluminescence.

What if there is no light? Primary manufacturers are missing. What if primary producers are missing? Secondary producers become nourishment for other animals e Every possible organic particle becomes a source of useful foodindispensable in such complex environments. Nothing is thrown away, everything recyclesthe carbon cycle works so. Excluding those who perform the photosynthesis, everything that lives the ocean is part of the category of predators And he must adapt to feeding on everything he can, including waste and “crumbs”. So here too the lumps of organic particulates of various origins, traveling one last time to the depths of the sea, become fundamental to give support to the food network.
The importance of marine snow in the food network
In such a vast and diversified environment like the ocean there is a need for a continuous movement and a constant production and export Of energy. This phenomenon starts from the most superficial layers, highly rich in light (fotic zone), to move and develop towards the deepest and most unknown layers of the oceans, where the light does not arrive (apotic area) and primary production is less. This mechanism of energy transfer in the form of organic matter allows correct operation seathe carbon cycle and all the biogeochemical cycles annexed.
We must imagine a large -scale phenomenon whose bricks, however, are small and many. Any debrite that contains carbon, nitrogen, sugars or complex molecules becomes a source of energy for others, regardless of size, its shape or its origin. Even the most small “snow” particlestherefore, become essential In such harsh and pressing environments.
What is certain is that not everything that lives along the water column feeds exclusively with debris, indeed. Many species, whether they are more superficial or profound waters, may not rely on the marine snow as well as, on the other hand, other organisms base their livelihoods on one diet exclusively based on organic debris, ingested or filtered along the water column or recovered from the seabed once sedimented. For many sea cucumbers and corals, for example, marine snow is the main source of energy on which they depend to survive.

These organic clusters also teem with bacteria, algae and microscopic organisms which cover them entirely by forming important communities around the fall particles. Not just food For brushes and necttonic species therefore (such as fish and large marine mammals), they are also useful surface for colonization.
Marine snow and climate change
New studies underline how these particles, in addition to the role in the food network, also play a climate regulatory role.
From a recent research published on Stanford Report it was discovered that the sedimentation process of marine snow is vital to understand the climate change. Being made up of a large amount of limestone shells, by phytoplankton, algae and plants, marine snow contributes to global carbon storage. Contains, incorporates, recovers – if we can say so – carbon through photosynthesis and the formation of the shells e blocks him on the bottom of the ocean by means of falling and sedimentation of the particles. Without this process, the atmosphere would be much warmer than it already is.
The problem presents itself when the seas already subjected to acidification And overheatingdissolve the limestone of the shells and intervene decreasing the storage capacity of the CO2. In addition, the study revealed that The navy snow sedates more slowly of the provisions for the presence of mucus All around that acts “like a parachute”, slowing down the descent towards the abysses. More time to fall, more time to be attached and disrupted by plankton and bacteria, less carbon that reaches the depths. This means Less carbon stockedmore co2 which remains in the most superficial layers and in the atmosphere with a consequent Increase in global temperatures.
That’s why studying the composition of the marine snow, the types of aggregation that form as well as the times and sedimentation flows becomes important: we can obtain important information on how to nutrition of the abysmal communities and deep, their diversity and distribution, as well as on the ways in which organic matter is used, recycled and mineralized and on the health status of the sea and land environments. We can recreate future scenarios, theorize models, learn to get to know even better the dynamics of biogeochemical cycles, matter, acidification phenomena, heat waves and the increase in water temperatures.