Marine snow moves carbon primarily by transporting it downwards through the ocean water column.
Marine snow refers to a continuous shower of mostly organic material that falls from the upper layers of the ocean to the deep seafloor. It consists of dead or dying plankton, algae, fecal matter, sand, soot, and other inorganic dust. This material contains carbon that was initially captured from the atmosphere by marine organisms through photosynthesis.
The movement of carbon via marine snow is a crucial part of the ocean's biological pump, transferring carbon from the surface to deeper waters. The fate of this carbon depends on how far the marine snow sinks before being broken down.
Here's how marine snow influences carbon movement based on depth:
- Carbon Sequestration (Deep Transport): If marine snow carries large amounts of carbon to significant depths, the carbon is effectively removed or sequestered from the surface ocean and the atmospheric greenhouse for thousands of years. This process helps regulate atmospheric CO2 levels over long timescales.
- Carbon Recycling (Shallow Transport): If marine snow is broken down and recycled near the surface (within the upper ocean layers), the carbon contained within it can quickly re-enter the surface ocean and atmosphere as carbon dioxide (CO2). CO2 is one of the main greenhouse gases, meaning shallow recycling contributes to the carbon cycle's rapid exchange between the ocean surface and the atmosphere.
In essence, marine snow acts like tiny conveyor belts, carrying carbon downwards. The speed of sinking and the depth at which decomposition occurs determine whether that carbon is locked away long-term or quickly returned to the surface environment.
