The Marine Carbon Cycle

Processes of Carbon Flow in the Oceanic Realm

Far less obvious to us than the terrestrial processes we just discussed, the cycling of carbon in the oceans is tremendously important to the global carbon cycle. For example, the oceans absorb a large portion of the CO₂ emitted through anthropogenic activities. As with the terrestrial part of the global carbon cycle, we will explore here the various processes involved in transferring carbon in and out of the oceans.

Below, we see a general depiction of the flows involved in the oceanic realm, along with the flow magnitudes.

Illustration to show flows involved in the oceanic realm, along with the flow magnitudes

Pathways and fluxes of carbon exchange in the oceans

Click for a text description of the Ocean carbon flows image.

This image illustrates the oceanic carbon cycle, focusing on carbon flow in marine environments. At the top center, a bright yellow sun labeled "FLOW" emits three yellow, wavy arrows downward, representing sunlight. Below the sun, the ocean is depicted in layers, with labels and red arrows showing carbon movement:

The top layer, labeled "SURFACE WATERS" in black, is a light blue section. A red arrow labeled "10 GtC/yr marine biota" points within this layer, indicating carbon uptake by marine life.
A red arrow labeled "ere" points from the surface waters into the atmosphere above, showing carbon dioxide exchange.
A red arrow labeled "92.2 GtC/yr downwelling" points downward from the surface waters to the deeper layers, representing carbon sinking.
Below the surface waters is a darker blue layer labeled "DEEP WATERS" in black. A red arrow labeled "105.6 GtC/yr bio-pump" points downward within this layer, showing the biological pump moving carbon deeper.
A red arrow labeled "90.6 GtC/yr upwelling" points upward from the deep waters back to the surface waters, indicating carbon rising through upwelling.
At the bottom, a brown layer labeled "OCEAN SEDIMENT" in black represents the ocean floor. A red arrow labeled "0.6 GtC/yr sedimentation" points downward from the deep waters into the sediment, showing carbon deposition.
On the right side, two red arrows extend from the deep waters and surface waters into the atmosphere, indicating carbon release back to the air.

The background is solid black, highlighting the ocean layers and carbon flow processes. All text is in black, and the arrows are red, providing clear contrast.