The carbon cycle does not just happen in the terrestrial environment (that means ‘on land’), it also happens in the marine environment (that means ‘in the sea’). The same main processes exist in the marine carbon cycle: photosynthesis, respiration, consumption, decay and fossilisation. In addition, you can see the blue arrows on the diagram that show the carbon flow between the ocean and atmosphere as well as the process of physical mixing. Zooplankton play an important role in removing carbon from the upper ocean and taking it to the deep ocean.