Probably the most dominant oceanographic feature of the northwestern Atlantic Ocean is the Gulf Stream.
The northern edge of that current is clearly visible
in the measurements of chlorophyll concentrations collected by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on April 3, 2003. The red and yellow colors in this image represent high chlorophyll concentrations in the sea’s surface waters. Chlorophyll is a primary pigment found in phytoplankton (microscopic marine plants). The green hues show moderately high chlorophyll concentrations, and blues represent low values.
As the Gulf Stream flows northeastward it forms meanders that occasionally pinch off to form clockwise-rotating warm-core rings to the north and counterclockwise-rotating cold-core rings to the south. Cold-core rings generally have higher chlorophyll concentrations and lower surface temperatures than the surrounding water, and a few of them can be seen in this image. Cold core rings tend to form in the east and then gradually
migrate towards the southwest. Some have been reported to remain recognizable for up to two years.
(Note: The phytoplankton in this image is not a hazard. The scene was posted for its scientific interest.)