Ocean color massive sediment load. The most important light-absorbing substance in the oceans is chlorophyll, which phytoplankton use to produce carbon by photosynthesis. Chlorophyll, a green pigment, makes phytoplankton preferentially absorb the red and blue portions of the light spectrum and reflect green light. Ocean regions with high concentrations of phytoplankton have shades of blue-green depending upon the type and density of the phytoplankton population there. The basic principle behind the remote sensing of ocean color from space is that the more phytoplankton is in the water, the greener it is. There are other substances that may be found dissolved in the
Chlorophyll directly absorbing light and performing charge separation events without the assistance of other chlorophyll pigments, but the probability of that happening under a given light intensity is small. Thus, the other chlorophylls in the photosystem and antenna pigment proteins all cooperatively absorb and funnel light energy to the reaction center. Besides chlorophyll "a", there are other pigments, called accessory pigments, which occur in these pigment–protein antenna complexes. Chlorophylls are numerous in types, but all are defined by the presence of a fifth ring beyond the four pyrrole-like rings. Most chlorophylls are classified as chlorins, which are reduced relatives to porphyrins