- Why is ocean water more clear around the equator?
The clarity of the water in certain regions of the ocean is due to a combination of factors. The first is the lack of plankton due to the lack of nutrients [1]. River water and rain runoff from land will make ocean muddy due to the silt [1]. Oceans with high concentrations of phytoplankton can appear blue-green to green, depending on the density [2]. The map in Feldman's office shows where there is little human interference and ocean water is perhaps the clearest on the planet [3]. This region is off the coast of Easter Island in the southeast Pacific Ocean, and the water is deep and remarkably clear due to its location in the middle of a giant oceanic gyre, or large circular current [3]. The purity of the water here, coupled with its depth, make the ocean here appear a deeper indigo than perhaps anywhere else [3].
The reason the ocean is more clear around the equator is due to the lack of plankton in that area due to the lack of nutrients [1]. plankton uses chlorophyll to produce carbon by photosynthesis, and because of this the ocean over regions with high concentrations of phytoplankton will appear as certain shades, from blue-green to green, depending upon the type and density of the phytoplankton population there [2]. The basic principle behind the remote sensing of ocean color from space is this: the more phytoplankton in the water, the greener it is....the less phytoplankton, the bluer it is [2]. The ocean is rarely clear, but is instead teeming with tiny plant and animal life or filled with suspended sediment or contaminants [3]. Color seen on the ocean's surface reflect what's going on in its vast depths [3].