Photosynthesis in the marine environment

Like plants on the land phytoplankton are packed full of chlorophyll giving them a green colour and giving them the ability to produce their own food through photosynthesis.

Photosynthesis is the chemical process in which chlorophyll uses the sun's energy to convert water and carbon dioxide into sugars and oxygen.

photosynthesis equation

Phytoplankton can only carry out this process where there is sufficent light intensity penetrating the sea water.  This area is called the photic zone and is often the top 100 metres of the ocean. 

When phytoplankton cells die they sink to the bottom of the ocean taking with them the carbon they have extracted from the atmosphere.  This process is called the carbon sink.                                                                                        More on photosynthesis